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IBM PowerPC 75 0GX and 750GL RISC Micro- processor User ’s Manual V ersion 1.2 March 27, 2006 Tit le P ag e.
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User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor 750gx_umTOC.fm.(1.2) March 27, 2006 Page 3 of 377 List of Figures ............. .......... .............. ......... .............. .............. ......... .............. .......... .
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Page 4 of 377 750gx_umTOC.fm.(1.2) March 27, 2006 2. Progr amming Model ....................... ......... .............. .......... .............. ......... .............. ..... 57 2.1 Power PC 750GX P rocessor Re gister Set .
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor 750gx_umTOC.fm.(1.2) March 27, 2006 Page 5 of 377 2.3.6.1 Sy stem Lin kage Ins tructions— OEA ............... ............. ................... ............. ................. 118 2.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Page 6 of 377 750gx_umTOC.fm.(1.2) March 27, 2006 4.2 Exception Rec ogn iti on and Prio riti es ......... ....... ...... ............. ...... ....... ...... ....... ............. .....
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor 750gx_umTOC.fm.(1.2) March 27, 2006 Page 7 of 377 5.1.8 MMU In structions and Regi ster Summa ry .......................... ............. ............. ................... .... 19 4 5.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Page 8 of 377 750gx_umTOC.fm.(1.2) March 27, 2006 6.6.1.3 Com pletio n-Unit Resou rce Requir ements ................ .................... ............. ............. ...... 237 6.7 Instruc tion Latenc y Summ ary .
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor 750gx_umTOC.fm.(1.2) March 27, 2006 Page 9 of 377 7.2.11.4 Ti me Base Ena ble (TBE N)—Input ..................... ............. .................... ............. .......... 274 7.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Page 10 o f 377 750gx_umTOC.fm.(1.2) March 27, 2006 8.6.2 No-DR TRY Mode ................ ............. .................... ............ .................... ............. ...........
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor 750gx_umTOC.fm.(1.2) March 27, 2006 Page 11 o f 377 11.1 Per formance-Mon itor Interr upt ............ ............. ................... ............. .................... ..........
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Page 12 o f 377 750gx_umTOC.fm.(1.2) March 27, 2006.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor 750gx_umLOF.fm.(1.2) March 27, 2006 List of Figures Page 13 o f 377 List of Figures Figure 1-1. 750GX M icroprocesso r Block D iagram ........... ................... ............. ..
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor List of Figures Page 14 o f 377 750gx_umLOF.fm.(1.2) March 27, 2006 Figure 8-5. First Level Address Pipelin ing ... ............. ............. ................... ............. ......
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor 750gx_umLOT.fm.(1.2) March 27, 2006 List of Tables Page 15 o f 377 List of T ables Table 1 -1. Architectur e-Defined Re gisters (Excluding SPRs) ...... .................... .........
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor List of Tables Page 16 o f 377 750gx_umLOT.fm.(1.2) March 27, 2006 Table 2-34. SPR Enc odings fo r 750GX- Defined Reg isters (mfspr) ................ .................... .............
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor 750gx_umLOT.fm.(1.2) March 27, 2006 List of Tables Page 17 o f 377 Table 5 -7. Table-Se arch Operati ons to Upd ate History Bits—TLB Hi t Case ... ............. ............. .....
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor List of Tables Page 18 o f 377 750gx_umLOT.fm.(1.2) March 27, 2006 Table 1 1-7. HID2 Check stop Control Bits .................. ............. ................... ............. ........
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_preface.fm.(1.2) March 27, 2006 Page 19 o f 377 About This Manu al This u ser’s man ual def ines the f unctional ity of the Power PC ® 75 0GX a nd 750GL RISC microp roce ssors.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Page 20 o f 377 gx_preface.fm.(1.2) March 27, 2006 Conventions Used in This Manual Notational Conventions mnemonics Inst ruction mnemon ics ar e shown in lower case bo ld. italics Italics indi cate vari able com mand param eters.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_preface.fm.(1.2) March 27, 2006 Page 21 o f 377 Terminology Conventions The foll owing tabl e describ es termino logy con ventions used in this man ual and the equiv alent ter minology used in t he Powe rPC Arch itecture specifi cation.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Page 22 o f 377 gx_preface.fm.(1.2) March 27, 2006 Using This Manual w ith the Pr ogramming Environments Manual Becaus e the Po werPC.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_01.fm.(1.2) March 27,2006 PowerPC 750GX Overview Page 23 o f 377 1. PowerPC 750GX Overview The IBM PowerPC 750GX red uced in str.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor PowerPC 750GX Overview Page 24 o f 377 gx_01.fm.(1.2) March 27,2006 and dat a block-a ddress-tr anslati on (IBA T and DBA T) array s, defined by the Po werPC Architec ture.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_01.fm.(1.2) March 27,2006 PowerPC 750GX Overview Page 25 o f 377 1.2 750GX Microprocessor Features This sec tion list s features of the 750GX. The interre lations hip of t hese featu res is sh own in Figure 1-1 on page 25.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor PowerPC 750GX Overview Page 26 o f 377 gx_01.fm.(1.2) March 27,2006 made ava ilabl e from the instruct ion cache . T ypi cally , if a fetch acc ess hits the B TIC, it pro vides the firs t two instruc tions i n the target s tream effectivel y yieldin g a ze ro-cycle b ranch.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_01.fm.(1.2) March 27,2006 PowerPC 750GX Overview Page 27 o f 377 – Retires as many as two ins tructio ns per cl ock. • Separate on- chip L1 instruc tion and data ca ches (H arvard archite cture) .
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor PowerPC 750GX Overview Page 28 o f 377 gx_01.fm.(1.2) March 27,2006 • TLBs a re hardw are-relo adable ( the page table sea rch is per formed b y hardwa re). • Bus interf ace featur es: – Enhance d 60x bus that pipelin es back-to- back re ads to a depth of fou r .
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_01.fm.(1.2) March 27,2006 PowerPC 750GX Overview Page 29 o f 377 1.2.1 Instruction Flow As show n in Fig ure 1-1 , 750GX M icrop.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor PowerPC 750GX Overview Page 30 o f 377 gx_01.fm.(1.2) March 27,2006 are flushed fr om the pro cessor, an d instruc tion fetch ing resumes along th e correct pa th.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_01.fm.(1.2) March 27,2006 PowerPC 750GX Overview Page 31 o f 377 For a mo re deta iled d iscussi on of instru ction co mplet ion, see Section 6.6.1, B ranch, D ispatch, and Comple - tion-Uni t Resource Requirem ents, o n page 2 37.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor PowerPC 750GX Overview Page 32 o f 377 gx_01.fm.(1.2) March 27,2006 1.2.2.3 Load/Store Unit (L SU) The LSU executes a ll load- and-sto re inst ructions and pro vides t he data-tran sfer interfac e between t he GPRs , FPRs, and t he data-c ache/mem ory sub system.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_01.fm.(1.2) March 27,2006 PowerPC 750GX Overview Page 33 o f 377 The 750G X suppo rts the f ollowing types of m emory tr anslati.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor PowerPC 750GX Overview Page 34 o f 377 gx_01.fm.(1.2) March 27,2006 written i nto an 8-w ord buffer. S ubsequen t doubl e words are fetch ed from eithe r the L2 c ache or the sys tem memory and written into the buff er.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_01.fm.(1.2) March 27,2006 PowerPC 750GX Overview Page 35 o f 377 instruc tion-c ache flash inval idate bit (HID 0[ICFI]). The inst ructio n cache can be lo cked by settin g HID0[ILOCK ].
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor PowerPC 750GX Overview Page 36 o f 377 gx_01.fm.(1.2) March 27,2006 The addres s and da ta buse s opera te independ ently . Address and data ten ures of a memory acces s are decouple d to prov ide m ore flex ible con trol of bu s tra ffic.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_01.fm.(1.2) March 27,2006 PowerPC 750GX Overview Page 37 o f 377 The syst em interf ace supp orts addr ess pi pelining , which al lows the address tenure o f one tran saction to overla p the data te nure of an other .
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor PowerPC 750GX Overview Page 38 o f 377 gx_01.fm.(1.2) March 27,2006 Note: A bar ov er a si gnal na me indi cates that the si gnal is active l ow—for ex ample, AR TRY (addr ess retry) and TS (tr ansfer st art).
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_01.fm.(1.2) March 27,2006 PowerPC 750GX Overview Page 39 o f 377 Signal f unctio nality i s desc ribed in detail in Chapter 7, S ignal Descr iptions, on page 249 and Chap ter 8, B us Interfac e Operation , on pag e 2 79.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor PowerPC 750GX Overview Page 40 o f 377 gx_01.fm.(1.2) March 27,2006 1.2. 9 Clo ckin g The 750G X requires a sing le system clock input, S YSCLK, that r epresen ts the bus interfa ce frequen cy.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_01.fm.(1.2) March 27,2006 PowerPC 750GX Overview Page 41 o f 377 The P owerPC Ar chitectu re cons ists of t he followi ng layers , and ad herence to the PowerP C Architec ture c an be descr ibed in terms of which of t he followi ng level s of the arc hitecture i s imple mented.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor PowerPC 750GX Overview Page 42 o f 377 gx_01.fm.(1.2) March 27,2006 1.4 PowerPC Registers and Programming Model The PowerP C Archit ecture de fines r egister -to-regi ster oper ations fo r most co mputati onal in structi ons.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_01.fm.(1.2) March 27,2006 PowerPC 750GX Overview Page 43 o f 377 The OEA defines nu mero us Speci al-Pur pose Reg isters that se.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor PowerPC 750GX Overview Page 44 o f 377 gx_01.fm.(1.2) March 27,2006 Table 1 -3 describe s the SPRs i n 750GX that are n ot defin ed by the PowerPC A rchite cture.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_01.fm.(1.2) March 27,2006 PowerPC 750GX Overview Page 45 o f 377 1.5 Instruction Set All Powe rPC ins tructio ns are e ncoded as single -word ( 32-bit) in stru ctions.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor PowerPC 750GX Overview Page 46 o f 377 gx_01.fm.(1.2) March 27,2006 – T ranslat ion -loo kas i de-bu ffer managemen t instr uc tions These cate gories do not ind icate the execu tion u nit that ex ecutes a particu lar inst ructio n or group o f inst ruc- tions.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_01.fm.(1.2) March 27,2006 PowerPC 750GX Overview Page 47 o f 377 1.5.2 750GX Micr o pro ce ssor In stru ctio n Set 750GX ins truction set is defi ned as fol lows. • 750GX p rovides ha rdware sup port for all PowerP C instru ctions.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor PowerPC 750GX Overview Page 48 o f 377 gx_01.fm.(1.2) March 27,2006 1.7 Exception Model The foll owing se ctions d escribe th e PowerP C exception model and the 750 GX impl ementation .
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_01.fm.(1.2) March 27,2006 PowerPC 750GX Overview Page 49 o f 377 The P owerPC A rchite cture su pports f our type s of exc eptions: 1.7.2 750GX Microprocessor Exception Implement ation The 750G X exce ption cl asses d escri bed above are show n in the Table 1 -4 .
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor PowerPC 750GX Overview Page 50 o f 377 gx_01.fm.(1.2) March 27,2006 T abl e 1-5. Ex cepti ons a nd Co nditi ons Exception T ype V ector Of fset (hex) Causing Conditions Reserve d 00000 — System reset 00100 Assertion of either HRESET or S RESET or a power-on reset.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_01.fm.(1.2) March 27,2006 PowerPC 750GX Overview Page 51 o f 377 1.8 Memory Management The foll owing sub section s descri be the memo ry-man agement fea tures of the Powe rPC Ar chitectu re, and the 750GX i mplementa tion.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor PowerPC 750GX Overview Page 52 o f 377 gx_01.fm.(1.2) March 27,2006 1.8.2 7 50GX Mic roprocessor Memory-Ma nagement Imp lementation The 750G X impl ements se parate MM Us for i nstruct ions and data.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_01.fm.(1.2) March 27,2006 PowerPC 750GX Overview Page 53 o f 377 Note: Figure 1-5 does not s how fea tures such as reserva tion stati ons and r ename bu ffers tha t reduce stalls and im prove ins truction throughp ut.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor PowerPC 750GX Overview Page 54 o f 377 gx_01.fm.(1.2) March 27,2006 • The executi on units proce ss instruc tions from their rese rvatio n stations usin g the operand s provid ed from dispatch, an d notif ies the c omple tion stage when the in structi on has fi nished ex ecution .
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_01.fm.(1.2) March 27,2006 PowerPC 750GX Overview Page 55 o f 377 In addition, the 750 GX allows softwa re-con trolled togg ling between two oper ating freq uencies .
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor PowerPC 750GX Overview Page 56 o f 377 gx_01.fm.(1.2) March 27,2006 The TAU i s controll ed throu gh the pri vileged mtspr a nd mfspr instru ctions to the four SP Rs prov ided for configur ing and c ontroll ing th e sensor c ontrol l ogic.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_02.fm.(1.2) March 27, 2006 Programming Model Page 57 o f 377 2. Programm ing Model This cha pter d escribes the 750 GX prog ramm ing model , empha sizing those featu res sp ecific t o the 750G X processo r and su mmariz ing those that are com mon to P owerPC pro cessors.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Programming M odel Page 58 o f 377 gx_02.fm.(1.2) March 27, 2006 Figure 2-1. Power PC 750GX Micro processor Program ming M odel—Reg.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_02.fm.(1.2) March 27, 2006 Programming Model Page 59 o f 377 The PowerPC UISA regis ters are user- level. Genera l Purpose Registe rs (GPRs) and Floating Point Register s (FPRs) are acces sed thro ugh in struction o perands .
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Programming M odel Page 60 o f 377 gx_02.fm.(1.2) March 27, 2006 “PowerPC R egiste r Set” of th e PowerP C Micropr ocessor Fa mily: T he Progra mming Env ironme nts Manual .
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_02.fm.(1.2) March 27, 2006 Programming Model Page 61 o f 377 – Memory -mana gem ent re gis ters • Block-A ddress Translation (BA T) Regi sters.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Programming M odel Page 62 o f 377 gx_02.fm.(1.2) March 27, 2006 Register 1 ( SRR1)” in Chapter 2, “Po werPC Regi ster Set” of the PowerPC Mi crop rocess or Fam - ily: T he Program ming En vironmen ts Manual for more i nformatio n.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_02.fm.(1.2) March 27, 2006 Programming Model Page 63 o f 377 – Hardware -Implementat ion-Depe ndent Regis ter 0 ( HID0)—This.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Programming M odel Page 64 o f 377 gx_02.fm.(1.2) March 27, 2006 2.1. 2 Power PC 750GX-Specific Re gisters This sec tion de scribe s registe rs that ar e defined for the 75 0GX but a re not included in the Pow erPC Ar chite c- ture.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_02.fm.(1.2) March 27, 2006 Programming Model Page 65 o f 377 2.1.2.2 Hardwar e-Implem entation-De pendent Register 0 (HID0) The H ardware-Im plemen tation-Depen dent Reg ister 0 (HID0) controls the state o f several functions within 750GX.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Programming M odel Page 66 o f 377 gx_02.fm.(1.2) March 27, 2006 9N A P 2 Nap mode ena ble. Operates in conjunct ion with MSR[POW]. 0 Nap mode disabled. 1 Nap mode enabled. Doze mode is invoked by s etting MSR[POW] wh ile this bit is set.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_02.fm.(1.2) March 27, 2006 Programming Model Page 67 o f 377 18 ILOCK Instruction-cac he lock 0 Normal operation. 1 Instruction cache is locked. A locked cac he supplies data norm ally on a hit, but is treated as a cache-inhibited transaction on a miss.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Programming M odel Page 68 o f 377 gx_02.fm.(1.2) March 27, 2006 22 SPD Speculative cache access disable 0 Speculative bus accesses to nonguarded space (G = 0) from both the instruction and data caches are enabled.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_02.fm.(1.2) March 27, 2006 Programming Model Page 69 o f 377 29 BHT Branch history table enable 0 BHT disabled.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Programming M odel Page 70 o f 377 gx_02.fm.(1.2) March 27, 2006 2.1.2.3 Hardwar e-Implem entation-De pendent Register 1 (HID1) The H ardware-Im plemen tation-Depen dent Reg ister 1 (HID1) reflects the state o f the PL L_CFG[0:4] s ignals.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_02.fm.(1.2) March 27, 2006 Programming Model Page 71 o f 377 2.1.2.4 Hardwar e-Implem entation-De pendent Register 2 (HID2) The H ardware-Im plemen tation-Depen dent Reg ister 2 (HID2) enables par ity.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Programming M odel Page 72 o f 377 gx_02.fm.(1.2) March 27, 2006 2.1.2.5 Performan ce-Mon itor Regist ers Thi s sectio n desc ribe s .
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_02.fm.(1.2) March 27, 2006 Programming Model Page 73 o f 377 User Monito r Mode Co ntrol Register 0 (UMMCR0 ) The content s of MM CR0 are refl ected to UM MCR0, whic h can be rea d by user- level soft ware.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Programming M odel Page 74 o f 377 gx_02.fm.(1.2) March 27, 2006 Monitor Mod e Control Register 1 (M MCR1) The M onitor M ode Contro l Registe r 1 (MM CR1) funct ions as an event s elector fo r Perform ance-Mo nitor Counter Re gisters 3 and 4 (PM C3 and P MC4).
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_02.fm.(1.2) March 27, 2006 Programming Model Page 75 o f 377 The foll owing tabl es lis t the sele ctabl e events a nd thei r encoding s: • T able 1 1-2, PMC1 Even ts—MMC R0 [19 :25 ] Sele ct Enc od ing s , on page 352.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Programming M odel Page 76 o f 377 gx_02.fm.(1.2) March 27, 2006 User Sa mpled Ins truction A ddress Register (USIA) The content s of S IA are refl ected to US IA, which can be read by user -level softw are.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_02.fm.(1.2) March 27, 2006 Programming Model Page 77 o f 377 2.1.3 Instruction Cache Throttling Control Register (ICTC) Reducing the rate o f inst ruction fetching can contr ol junc tion tempe rature w ithout t he comple xity an d over- head of dynamic clock c ontrol.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Programming M odel Page 78 o f 377 gx_02.fm.(1.2) March 27, 2006 2.1.4 Thermal-Ma nagement Re gisters ( THRMn) The on-ch ip therm al-.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_02.fm.(1.2) March 27, 2006 Programming Model Page 79 o f 377 2.1.4.2 Thermal -Managem ent Register 3 (THRM3) The THR M3 register is used to enabl e the ther mal assis t unit and t o contro l the timi ng of the ou tput sa mple compari son.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Programming M odel Page 80 o f 377 gx_02.fm.(1.2) March 27, 2006 2.1.4.3 Thermal -Managem ent Register 4 (THRM4) Due to proc ess and t hermal sens or varia tions, a temperat ure offset is prov ided that c an be read via an mfspr instruc tion to THRM 4.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_02.fm.(1.2) March 27, 2006 Programming Model Page 81 o f 377 2.1.5 L 2 Cache Co ntro l Register (L2CR) The L2 Ca che Contr ol Regis ter is a superv isor-level , impleme ntatio n-specifi c SPR us ed to conf igure an d operate t he L2 cache.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Programming M odel Page 82 o f 377 gx_02.fm.(1.2) March 27, 2006 2.2 Operand Conventions This sec tion des cribes the operand conventi ons as they are rep resented in two level s of the P owerPC A rchi- tecture— UISA and V EA.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_02.fm.(1.2) March 27, 2006 Programming Model Page 83 o f 377 2.2.3 Floating-Point Operand and Execution Models—UISA The IEEE 754-1 985 standa rd defines convention s for 64-bit and 32-bit arithm etic.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Programming M odel Page 84 o f 377 gx_02.fm.(1.2) March 27, 2006 2.2.3.3 Time-Critical Floating-Point Op eration For time- critica l .
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_02.fm.(1.2) March 27, 2006 Programming Model Page 85 o f 377 Table 2 -6 summarize s the mode b ehavior fo r results .
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Programming M odel Page 86 o f 377 gx_02.fm.(1.2) March 27, 2006 2.3 Instruction Set Summary This sec tion des cribes in structi ons and a ddress ing modes defined fo r the 750G X.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_02.fm.(1.2) March 27, 2006 Programming Model Page 87 o f 377 that the archite cture spec ificati on refer s to sim plified m nemonic s as ext ended mnem onics.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Programming M odel Page 88 o f 377 gx_02.fm.(1.2) March 27, 2006 2.3.1.3 Illegal Instruc tion Class Illegal i nstruc tions ca n be grou ped in to the fo llowing cate gories : • Instructio ns not defined i n the Power PC Archi tecture.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_02.fm.(1.2) March 27, 2006 Programming Model Page 89 o f 377 2.3.1.4 Reserve d Instruct ion Class Reserved i nstruc tions ar e alloca ted to sp ecific i mplementa tion- dependent p urposes not defin ed by the PowerPC Archit ecture.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Programming M odel Page 90 o f 377 gx_02.fm.(1.2) March 27, 2006 2.3.2.3 Effective Addr ess Calcu lation An effe ctive ad dress is th.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_02.fm.(1.2) March 27, 2006 Programming Model Page 91 o f 377 For exam ple, if t he mtmsr sets the MSR[P R] bit, unless an isy nc.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Programming M odel Page 92 o f 377 gx_02.fm.(1.2) March 27, 2006 Summa ry” in the Powe rPC Micropr ocessor Fa mily: T he Program ming E nvironment s Manu al .
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_02.fm.(1.2) March 27, 2006 Programming Model Page 93 o f 377 Although there is no Su btract Im mediate in stru ction, it s effect can be a chieved by usin g an addi instruct ion with the immedia te operand negated .
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Programming M odel Page 94 o f 377 gx_02.fm.(1.2) March 27, 2006 Integer L ogical In stru ctions The log ical ins tructi ons shown in Tabl e 2-9 on page 94 perform bit-paral lel oper ations on the specifi ed oper- ands.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_02.fm.(1.2) March 27, 2006 Programming Model Page 95 o f 377 The inte ger rotate i nstruc tions ar e summar ized in Table 2-1 0 . For more i nformation, see the Po werPC Micro- processo r Fami ly: The Progra mming En vironme nts Manua l .
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Programming M odel Page 96 o f 377 gx_02.fm.(1.2) March 27, 2006 Double -preci sion arith metic i nstruc tions, ex cept tho se invol ving mul tipli cation ( fmul , fmadd , fms ub , fnmadd , fnmsub ) execute wi th the sam e late ncy as t heir singl e-precis ion e quivalen ts.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_02.fm.(1.2) March 27, 2006 Programming Model Page 97 o f 377 Example s of us es of these ins tructions to pe rform var ious conv.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Programming M odel Page 98 o f 377 gx_02.fm.(1.2) March 27, 2006 Note: The Pow erPC Arch itecture states th at, in some im plementa t.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_02.fm.(1.2) March 27, 2006 Programming Model Page 99 o f 377 Little En dian M isalign ed Acce sses The 750G X supp orts misa ligne d single regist er load- and-st ore acc esses in littl e-endian mode w ithout ca using an alignm ent excep tion.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Programming M odel Page 100 of 377 gx_02.fm.(1.2) March 27, 2006 Imp leme nta ti on N ote s —The following notes des cribe the 750G.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_02.fm.(1.2) March 27, 2006 Programming Model Page 101 o f 377 Integer Store Instr uctions For in teger sto re inst ruction s, the co ntents o f the s ource regi ster ( r S) are stor ed into the byte, half word, or word in m emory a ddressed b y the EA .
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Programming M odel Page 102 of 377 gx_02.fm.(1.2) March 27, 2006 If store gathering is enabled and the stores do not f all under th e.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_02.fm.(1.2) March 27, 2006 Programming Model Page 103 o f 377 Integer L oad-and- S tore String Instru ctions The inte ger load-a nd-store s tring ins truction s allow m ovement o f data from memory to register s, or fro m registe rs to memor y, without conc ern for a lignment.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Programming M odel Page 104 of 377 gx_02.fm.(1.2) March 27, 2006 For softwa re compa tibil ity, th e other two mode e ncodings, imp recise-n onrecover able mod e and i mpre- cise -rec over able mode , de faul t to t he pr ecis e mod e .
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_02.fm.(1.2) March 27, 2006 Programming Model Page 105 o f 377 Table 2 -24 summa rizes the si ngle -preci sion and doubl e-precis ion flo ating-poi nt store an d stfiwx i nstruct ions.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Programming M odel Page 106 of 377 gx_02.fm.(1.2) March 27, 2006 Archi tecturally , all si ngle-pr ecisio n and doub le-prec ision f loatin g-point n umbers are repre sented in double - precisio n form at within t he 750GX .
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_02.fm.(1.2) March 27, 2006 Programming Model Page 107 o f 377 specula tively executed instruc tions a nd restore the mac hine sta te to im mediately after th e branch . This cor - rection can be do ne immedi ately up on resoluti on of th e Conditio n Registers bits.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Programming M odel Page 108 of 377 gx_02.fm.(1.2) March 27, 2006 T rap Inst ruction s The tr ap instruc tio ns show n in Tabl e 2-29 are prov ided to te st for a specif ied set of c ondition s.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_02.fm.(1.2) March 27, 2006 Programming Model Page 109 o f 377 Imp leme nta ti on N ote : The P owerPC A rchitecture i ndicate s .
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Programming M odel Page 110 of 377 gx_02.fm.(1.2) March 27, 2006 DBAT7L 575 10001 11111 Su pervisor (OEA) Both DBAT7U 574 10001 11110.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_02.fm.(1.2) March 27, 2006 Programming Model Page 111 o f 377 TBL 2 268 01000 01100 User (VEA) mfspr 284 01000 11100 Supervisor (OEA) mtspr TBU 2 269 01000 01101 User (VEA) mfspr 285 01000 11101 Supervisor (OEA) mtspr XER 1 00000 00001 User (UI SA) B oth T able 2-33.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Programming M odel Page 112 of 377 gx_02.fm.(1.2) March 27, 2006 Enco dings for th e 750G X-speci fic SPRs are lis ted in Table 2-34 .
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_02.fm.(1.2) March 27, 2006 Programming Model Page 113 o f 377 2.3.4.7 Memory Synchronization Inst ructions —UISA Memory synchr.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Programming M odel Page 114 of 377 gx_02.fm.(1.2) March 27, 2006 Table 2 -36 shows th e mftb instruc tion.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_02.fm.(1.2) March 27, 2006 Programming Model Page 115 o f 377 2.3.5.3 Memory Co ntrol Ins tructions—V EA Memory control instru.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Programming M odel Page 116 of 377 gx_02.fm.(1.2) March 27, 2006 Table 2 -38 summar izes th e cache ins tructio ns define d by the VEA . Note th at these i nstruction s are ac ces- sible to user-lev el progra ms.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_02.fm.(1.2) March 27, 2006 Programming Model Page 117 o f 377 2.3.5.4 Optional Extern al Contro l Instru ctions The P owerPC Ar .
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Programming M odel Page 118 of 377 gx_02.fm.(1.2) March 27, 2006 output t he 4-bit re source ID (RID) field l ocated in the EAR. The eciwx in structi on als o loads a word fr om the data bu s that is output by the sp ecial de vice .
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_02.fm.(1.2) March 27, 2006 Programming Model Page 119 o f 377 2.3.6.3 Memory Con trol Instr uctions—OE A Memory control instruc tions i nclude th e followin g. • Cache-m anagement i nstruc tions (su pervisor -level and user-lev el).
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Programming M odel Page 120 of 377 gx_02.fm.(1.2) March 27, 2006 T ra nslati on Looka side Buffer Ma nageme nt Instruc tions—(O EA).
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_03.fm.(1.2) March 27, 2006 Instruction- Cache and Data-Cache Opera tion Page 121 o f 377 3.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Instruction-Cache an d Data-Cache Operation Page 122 of 377 gx_03.fm.(1.2) March 27, 2006 Both cac hes are tig htly cou pled into the 750GX ’s bus interface u nit (BIU) to allow efficien t access to the system memo ry cont roller and ot her bus master s.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_03.fm.(1.2) March 27, 2006 Instruction- Cache and Data-Cache Opera tion Page 123 o f 377 3.1 D ata-Cache Orga nization The data cach e is organi zed a s 128 set s of eight ways as shown in Figure 3-2 .
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Instruction-Cache an d Data-Cache Operation Page 124 of 377 gx_03.fm.(1.2) March 27, 2006 3.2 Instruction-C ache Organization The inst ructio n cache also co nsists of 128 se ts of e ight ways , as sho wn in Fi gure 3- 3 on page 125.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_03.fm.(1.2) March 27, 2006 Instruction- Cache and Data-Cache Opera tion Page 125 o f 377 3.3 Memory and Cache Coher ency The prima ry obje ctive of a cohere nt memory s ystem i s to provi de the sam e image of memory to all dev ices using the system .
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Instruction-Cache an d Data-Cache Operation Page 126 of 377 gx_03.fm.(1.2) March 27, 2006 These b its allow bo th unip rocess or and m ultiproc essor s ystem des igns to exploit n umerous system-l evel perform ance opti mization s.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_03.fm.(1.2) March 27, 2006 Instruction- Cache and Data-Cache Opera tion Page 127 o f 377 The 750G X provid es dedic ated ha rdware t o provide m emory c oherenc y by sn ooping bus transa ction s.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Instruction-Cache an d Data-Cache Operation Page 128 of 377 gx_03.fm.(1.2) March 27, 2006 Sec t ion 3.7 , MEI St ate Tr ansactio ns, on page 147 provid es a detai led lis t of MEI tr ansitio ns for var ious ope r- ations an d WIM bit settin gs.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_03.fm.(1.2) March 27, 2006 Instruction- Cache and Data-Cache Opera tion Page 129 o f 377 Anothe r conside ratio n is pag e table al iasing.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Instruction-Cache an d Data-Cache Operation Page 130 of 377 gx_03.fm.(1.2) March 27, 2006 3.3.5 PowerPC 750GX-In itiated Loa d/Store Oper ations Load-and -store ope rations are assum ed to be weakly ord ered on t he 750GX.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_03.fm.(1.2) March 27, 2006 Instruction- Cache and Data-Cache Opera tion Page 131 o f 377 atomic a ccess to n oncohe rent memo ry. For deta iled info rmation o n these i nstruct ions, se e Chap ter 2, Pr o- grammin g Model, o n page 57.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Instruction-Cache an d Data-Cache Operation Page 132 of 377 gx_03.fm.(1.2) March 27, 2006 3.4.1.1 Data-Cac he Flash Invalidat ion The data cach e is autom aticall y inval idated whe n the 75 0GX is powe red up an d during a hard reset.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_03.fm.(1.2) March 27, 2006 Instruction- Cache and Data-Cache Opera tion Page 133 o f 377 3.4.1.4 Instructio n-Cache Flash Invali dation The inst ructio n cache is automa tically inva lidated wh en the 7 50GX is po wered up and dur ing a hard reset .
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Instruction-Cache an d Data-Cache Operation Page 134 of 377 gx_03.fm.(1.2) March 27, 2006 are not bro adcast, unles s broadcas t is enable d through the HID 0[ABE] co nfigurati on bit.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_03.fm.(1.2) March 27, 2006 Instruction- Cache and Data-Cache Opera tion Page 135 o f 377 For this reason, av oid usin g dcbz for.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Instruction-Cache an d Data-Cache Operation Page 136 of 377 gx_03.fm.(1.2) March 27, 2006 3.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_03.fm.(1.2) March 27, 2006 Instruction- Cache and Data-Cache Opera tion Page 137 o f 377 Figure 3-5.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Instruction-Cache an d Data-Cache Operation Page 138 of 377 gx_03.fm.(1.2) March 27, 2006 If all eig ht blocks are valid, then a b lock is sel ected for replaceme nt accor ding to th e PLRU bit encoding s shown in Ta bl e 3-3 .
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_03.fm.(1.2) March 27, 2006 Instruction- Cache and Data-Cache Opera tion Page 139 o f 377 The d ata-cache flush assi st bit, HID0 [DCFA], sim plifies the so ftware flushi ng proc ess.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Instruction-Cache an d Data-Cache Operation Page 140 of 377 gx_03.fm.(1.2) March 27, 2006 Burst tra nsact ions on th e 750GX alway s transf er eight words of d ata at a tim e, and are alig ned to a dou ble- word boun dary.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_03.fm.(1.2) March 27, 2006 Instruction- Cache and Data-Cache Opera tion Page 141 o f 377 3.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Instruction-Cache an d Data-Cache Operation Page 142 of 377 gx_03.fm.(1.2) March 27, 2006 3.6.3 Snooping The 750G X maint ains data-cac he coheren cy in ha rdware b y coord inating a ctivity be tween the data cac he, the bus i nterface log ic, the L2 cache, a nd the m emory sy stem.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_03.fm.(1.2) March 27, 2006 Instruction- Cache and Data-Cache Opera tion Page 143 o f 377 the data tr ansactions to mem ory in or der).
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Instruction-Cache an d Data-Cache Operation Page 144 of 377 gx_03.fm.(1.2) March 27, 2006 Write-with-kill 00110 A write-with-kill operation is a burst transaction initiated due to a castout, caching- enabled push, or s noop copy-back.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_03.fm.(1.2) March 27, 2006 Instruction- Cache and Data-Cache Opera tion Page 145 o f 377 3.6.5 T ransfer Attr ibutes In addition to the address and transfe r type signal s, the 750GX supports the tr ansfer attribute signals : TBST , TSIZ[0–2], WT , CI , and GB L .
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Instruction-Cache an d Data-Cache Operation Page 146 of 377 gx_03.fm.(1.2) March 27, 2006 T able 3-6.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_03.fm.(1.2) March 27, 2006 Instruction- Cache and Data-Cache Opera tion Page 147 o f 377 3.7 M EI S t ate T ransactions Table 3 -7 shows ME I state transit ions for variou s opera tions.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Instruction-Cache an d Data-Cache Operation Page 148 of 377 gx_03.fm.(1.2) March 27, 2006 dcbst Data -cache- block store No xxx I, E Sam e dcbst . — Pass clean. Clean Same Same No act ion.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_03.fm.(1.2) March 27, 2006 Instruction- Cache and Data-Cache Opera tion Page 149 o f 377 tlbi e TLB invalidate No xxx x x Pas s TL B I. — No action. — sync Synchroniza- tion No xxx x x Pass sync.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Instruction-Cache an d Data-Cache Operation Page 150 of 377 gx_03.fm.(1.2) March 27, 2006.
User’s Ma nua l IBM PowerPC 750 GX and GL RISC Micropr o ces sor gx_04.fm.(1.2) March 27, 2006 Exceptions Page 151 o f 377 4. Exceptions The operat ing env ironme nt architec ture (OE A) portion of .
User’s M anual IBM PowerPC 750GX and GL RISC Micropro ces sor Exceptions Page 152 of 377 gx_04.fm.(1.2) March 27, 2006 Note: The PowerPC A rchitectu re docu mentation ref ers to exc eptions a s interrupts .
User’s Ma nua l IBM PowerPC 750 GX and GL RISC Micropr o ces sor gx_04.fm.(1.2) March 27, 2006 Exceptions Page 153 o f 377 4.2 Exception Recogni tion and Priorities Excepti ons are roughly pr ioritize d by e xceptio n class, as follows . 1. Nonmask able, async hronous excepti ons have priority over all other exc eptio ns.
User’s M anual IBM PowerPC 750GX and GL RISC Micropro ces sor Exceptions Page 154 of 377 gx_04.fm.(1.2) March 27, 2006 • Exception s cause d by asy nchronous events (inter rupts). These e xceptio ns are fu rther dis tinguish ed by whether th ey are m askable and recov erable.
User’s Ma nua l IBM PowerPC 750 GX and GL RISC Micropr o ces sor gx_04.fm.(1.2) March 27, 2006 Exceptions Page 155 o f 377 T abl e 4-3. Ex cepti on Pr iori tie s Priority Exception Cause Asynchronou.
User’s M anual IBM PowerPC 750GX and GL RISC Micropro ces sor Exceptions Page 156 of 377 gx_04.fm.(1.2) March 27, 2006 System reset a nd machi ne-check exc eptions ca n occur a t any time and are not delaye d even if an ex ception is being handled. As a res ult, stat e informa tion fo r an interr upted ex ception m ight be lost.
User’s Ma nua l IBM PowerPC 750 GX and GL RISC Micropr o ces sor gx_04.fm.(1.2) March 27, 2006 Exceptions Page 157 o f 377 4.3.2 Machine St atu s Save/Re store R egister 1 (S RR1) SRR1 is us ed t o .
User’s M anual IBM PowerPC 750GX and GL RISC Micropro ces sor Exceptions Page 158 of 377 gx_04.fm.(1.2) March 27, 2006 4.3.3 Machine St ate Register (MSR) Reserved POW Reserved ILE EE PR FP ME FE0 S.
User’s Ma nua l IBM PowerPC 750 GX and GL RISC Micropr o ces sor gx_04.fm.(1.2) March 27, 2006 Exceptions Page 159 o f 377 The IEEE flo ating-po int excep tion mo de bits (FE 0 and FE1) tog ether defi ne whether fl oating- point excepti ons are hand led prec isely, imprec isely, o r whether they ar e take n at all.
User’s M anual IBM PowerPC 750GX and GL RISC Micropro ces sor Exceptions Page 160 of 377 gx_04.fm.(1.2) March 27, 2006 4.3.4 Enabling and Disabling Exceptions When a c ondition e xists t hat mig ht cause an excep tion to be gener ated, it mus t be de termined whe ther th e excepti on is ena bled fo r that co ndition.
User’s Ma nua l IBM PowerPC 750 GX and GL RISC Micropr o ces sor gx_04.fm.(1.2) March 27, 2006 Exceptions Page 161 o f 377 0x000 n_n nnn . If IP i s set, except ions are vec tored to the physical ad dress 0x FFF n_nnnn .
User’s M anual IBM PowerPC 750GX and GL RISC Micropro ces sor Exceptions Page 162 of 377 gx_04.fm.(1.2) March 27, 2006 4.4 Process Switching The foll owing ins tructions are use ful for res toring p roper cont ext du ring proc ess swit ching: • The Sy nchr oni za tio n ( sync ) instruc tion ord ers the e ffects of in structi on exec ution.
User’s Ma nua l IBM PowerPC 750 GX and GL RISC Micropr o ces sor gx_04.fm.(1.2) March 27, 2006 Exceptions Page 163 o f 377 The set ting of the excep tion pre fix bit (IP ) determ ines how e xceptio ns are v ectored . If the bit i s clea red, excepti ons are vec tored to the physic al addres s 0x000 n _nnnn (where n nnnn is the vecto r offset).
User’s M anual IBM PowerPC 750GX and GL RISC Micropro ces sor Exceptions Page 164 of 377 gx_04.fm.(1.2) March 27, 2006 4.5.1.1 Soft Rese t If SRE SET is ass erted, the processor is firs t put in a recover able sta te.
User’s Ma nua l IBM PowerPC 750 GX and GL RISC Micropr o ces sor gx_04.fm.(1.2) March 27, 2006 Exceptions Page 165 o f 377 The har d reset ex ceptio n is a no nrecover able, nonm aska ble, asy nchronous exce ption.
User’s M anual IBM PowerPC 750GX and GL RISC Micropro ces sor Exceptions Page 166 of 377 gx_04.fm.(1.2) March 27, 2006 T able 4-7. Settings Ca used b y Hard Rese t Register Setting BATs Un known Cache, instruction cache, and data cache All blocks are unc hanged from before HRES ET .
User’s Ma nua l IBM PowerPC 750 GX and GL RISC Micropr o ces sor gx_04.fm.(1.2) March 27, 2006 Exceptions Page 167 o f 377 The foll owing is also tr ue after a hard re set oper ation: • Externa l check stops are enab led. • The on-ch ip test i nterface has given c ontrol o f the I/Os to the rest o f the chip for func tional us e.
User’s M anual IBM PowerPC 750GX and GL RISC Micropro ces sor Exceptions Page 168 of 377 gx_04.fm.(1.2) March 27, 2006 A TEA indicat ion o n the b us can re sult fr om any load or stor e oper ation i nitiated by the pro cessor.
User’s Ma nua l IBM PowerPC 750 GX and GL RISC Micropr o ces sor gx_04.fm.(1.2) March 27, 2006 Exceptions Page 169 o f 377 When a machine -check exc eption is take n, instruct ion fetc hing re sumes at offset 0x00200 fr om the ph ysical base addr ess in dicated b y MSR [IP].
User’s M anual IBM PowerPC 750GX and GL RISC Micropro ces sor Exceptions Page 170 of 377 gx_04.fm.(1.2) March 27, 2006 stops di spatchi ng and waits f or all p ending in structi ons to co mplete . This all ows any i nstruc tions in progress that nee d to take a n except ion to do s o before the exter nal inter rupt is taken.
User’s Ma nua l IBM PowerPC 750 GX and GL RISC Micropr o ces sor gx_04.fm.(1.2) March 27, 2006 Exceptions Page 171 o f 377 4.5.8 Floating-Po int Una vailable Exce ption (0 x00800) The floa ting-poi nt unavai lable ex ception is im plemented as def ined in th e PowerP C Architec ture.
User’s M anual IBM PowerPC 750GX and GL RISC Micropro ces sor Exceptions Page 172 of 377 gx_04.fm.(1.2) March 27, 2006 4.5.13 Performance-Monitor I nterrupt (0x00 F00) The 750G X microp rocess or pr.
User’s Ma nua l IBM PowerPC 750 GX and GL RISC Micropr o ces sor gx_04.fm.(1.2) March 27, 2006 Exceptions Page 173 o f 377 4.5.14 Instruct ion Addre ss Brea kpoint Exc eption ( 0x01300 ) An in struc.
User’s M anual IBM PowerPC 750GX and GL RISC Micropro ces sor Exceptions Page 174 of 377 gx_04.fm.(1.2) March 27, 2006 Like the external interrupt , a system m anagem ent interru pt is signa led to t he 750GX by the as sertion of an input sign al.
User’s Ma nua l IBM PowerPC 750 GX and GL RISC Micropr o ces sor gx_04.fm.(1.2) March 27, 2006 Exceptions Page 175 o f 377 The t hermal- managemen t interrupt is sim ilar to the s ystem m anagement a nd ex ternal inter rupt.
User’s M anual IBM PowerPC 750GX and GL RISC Micropro ces sor Exceptions Page 176 of 377 gx_04.fm.(1.2) March 27, 2006 4.5.19 Exception Latencies Latencie s for tak ing var ious exce ptions ar e vari able bas ed on the s tate of t he machin e when c ondition s to produce an exc eption occur.
User’s Ma nua l IBM PowerPC 750 GX and GL RISC Micropr o ces sor gx_04.fm.(1.2) March 27, 2006 Exceptions Page 177 o f 377 4.5.21 Timer Facilities At power -on r eset (POR) , the 750G X initi alizes.
User’s M anual IBM PowerPC 750GX and GL RISC Micropro ces sor Exceptions Page 178 of 377 gx_04.fm.(1.2) March 27, 2006.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_05.fm.(1.2) March 27, 2006 Memory M anagement Page 179 o f 377 5. Memo ry Man agement This ch apter describe s the 750GX mic rop.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Memory Management Page 180 of 377 gx_05.fm.(1.2) March 27, 2006 Basic features of the 7 50GX MMU imple mentation defined by the O EA .
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_05.fm.(1.2) March 27, 2006 Memory M anagement Page 181 o f 377 5.1.1 M emory Add ressing A progr am referen ces memo ry using t .
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Memory Management Page 182 of 377 gx_05.fm.(1.2) March 27, 2006 the mem ory subs ystem.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_05.fm.(1.2) March 27, 2006 Memory M anagement Page 183 o f 377 Figure 5-1. MMU Concep tual Block Diagram Optional Instructio n A.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Memory Management Page 184 of 377 gx_05.fm.(1.2) March 27, 2006 Figure 5-2. Power PC 750GX Mi cropr ocessor IM MU Bl ock Diag ram BPU.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_05.fm.(1.2) March 27, 2006 Memory M anagement Page 185 o f 377 Figure 5-3. 750GX Mi croproc essor D MMU Bloc k Diagra m DTLB DBA.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Memory Management Page 186 of 377 gx_05.fm.(1.2) March 27, 2006 5.1.3 Address-T ranslat ion Mechan isms PowerPC proces sors supp ort .
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_05.fm.(1.2) March 27, 2006 Memory M anagement Page 187 o f 377 When t he proce ssor gener ates an access, an d the c orrespond i.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Memory Management Page 188 of 377 gx_05.fm.(1.2) March 27, 2006 The no-ex ecute opti on prov ided in th e segment registe r lets th e operating system program determi ne whether in structi ons can be fetched from an area of memory.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_05.fm.(1.2) March 27, 2006 Memory M anagement Page 189 o f 377 5.1.6 General Fl ow of MMU Ad dress T ranslation The foll owing se ctions d escribe th e general flow use d by PowerP C process ors to tran slate effe ctive address es to vi rtual an d then phy sical addr esses.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Memory Management Page 190 of 377 gx_05.fm.(1.2) March 27, 2006 5.1.6.2 Page-A ddress-Trans lation Selec tion If addres s trans lation i s enabled and the effect ive addr ess inf ormation does n ot match a BAT arr ay entry , then the segment descriptor must be locat ed.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_05.fm.(1.2) March 27, 2006 Memory M anagement Page 191 o f 377 Figure 5-6. General Flow of Page and D irect- S t ore Inter face .
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Memory Management Page 192 of 377 gx_05.fm.(1.2) March 27, 2006 If the T b it in the S egment Regi ster is cleared (S R[T] = 0 ), then pag e-addre ss transl ation is selecte d. The informat ion in the segme nt des criptor i s then us ed to ge nerate the 52-bit v irtual address .
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_05.fm.(1.2) March 27, 2006 Memory M anagement Page 193 o f 377 The state sav ed by the proces sor for each of these exce ptions con tains inform ation tha t identifies the ad dress of the faili ng instru ction.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Memory Management Page 194 of 377 gx_05.fm.(1.2) March 27, 2006 5.1.8 MMU Instru ctions and Re gister Su mmary The MMU instruc tions and reg isters allo w the operating sy stem to set up the block- address- transla tion areas and the pag e table s in mem ory.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_05.fm.(1.2) March 27, 2006 Memory M anagement Page 195 o f 377 Figure 5- 6 summa rizes the reg isters tha t the op erating sy stem use s to progra m the 750G X’s MMU s. Th ese registe rs are access ible to s uper visor-lev el so ftware onl y.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Memory Management Page 196 of 377 gx_05.fm.(1.2) March 27, 2006 For infor matio n on the sy nchroniz ation req uiremen ts for chan ges to MSR[IR] and M SR[DR], see Section 2.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_05.fm.(1.2) March 27, 2006 Memory M anagement Page 197 o f 377 page-add ress tran slation and not for transl ations ma de with the BAT mec hanism or for a ccesses that corre- spond to d irect-st ore (T = 1) segments .
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Memory Management Page 198 of 377 gx_05.fm.(1.2) March 27, 2006 • Accesse s that cau se exce ptions an d are not complete d.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_05.fm.(1.2) March 27, 2006 Memory M anagement Page 199 o f 377 For more informat ion, see “ Page His tory Re cording ” in C hapter 7, “Memory M anagem ent,” of the Power PC Microp rocess or Fam ily: The P rogram ming Env ironmen ts Manual .
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Memory Management Page 200 of 377 gx_05.fm.(1.2) March 27, 2006 Each TLB co ntains 12 8 entries organi zed as a 2-way s et-associ ative ar ray wit h 64 se ts as sh own in Figure 5- 7 for the DTLB (the I TLB or ganizati on is the same).
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_05.fm.(1.2) March 27, 2006 Memory M anagement Page 201 o f 377 To uniq uely ide ntify a TLB ent ry as the r equired PTE, ea ch TLB entry cont ains, in additi on to the PTE, a n additiona l 4-bit field cal led the E xtended P age Index (EPI).
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Memory Management Page 202 of 377 gx_05.fm.(1.2) March 27, 2006 Other th an the pos sible TLB miss o n the next instruc tion pre fetc.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_05.fm.(1.2) March 27, 2006 Memory M anagement Page 203 o f 377 Figure 5-8. Page-Ad dress- T ranslatio n Flow—T LB Hit (See The.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Memory Management Page 204 of 377 gx_05.fm.(1.2) March 27, 2006 5.4.5 Page T able- Sea rch Operat ion If the trans lation i s not found i n the TLB s (a TLB m iss), the 75 0GX ini tiates a ta ble-sea rch operat ion, whi ch is describe d in thi s secti on.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_05.fm.(1.2) March 27, 2006 Memory M anagement Page 205 o f 377 Figure 5-9. Prim ary Pa ge T abl e Search (From Figure 5-10 on pa.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Memory Management Page 206 of 377 gx_05.fm.(1.2) March 27, 2006 The l oad stor e unit (LSU ) initia tes out-o f-order acc esses w ithout k nowin g whether it i s legal to do so.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_05.fm.(1.2) March 27, 2006 Memory M anagement Page 207 o f 377 5.4.6 Page T able Updates When T LBs ar e implem ented (as in the 750GX), t hey a re defin ed as non coher ent caches of t he page ta bles.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Memory Management Page 208 of 377 gx_05.fm.(1.2) March 27, 2006.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_06.fm.(1.2) March 27, 2006 Instruction Timing Page 209 o f 377 6. Instruction Ti ming This cha pter d escribes how the PowerPC 7 50GX mi croproce ssor fe tches, di spatche s, and ex ecutes i nstruc- tions and ho w it reports the r esults of in stru ction execut ion.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor In str ucti on T imi ng Page 210 of 377 gx_06.fm.(1.2) March 27, 2006 Fetch The process o f brin ging ins tructio ns from t he syste m memory (such as a cache or the main m emory) i nto the ins tructio n queue.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_06.fm.(1.2) March 27, 2006 Instruction Timing Page 211 o f 377 6.2 Instruction T iming Overvi ew The 750G X design m inimiz es a.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor In str ucti on T imi ng Page 212 of 377 gx_06.fm.(1.2) March 27, 2006 • 64-bit floa ting- point unit (FPU) • Load/stor e unit ( LSU) • Syst em regi ster unit (S RU) Figure 6- 1 repres ents a gene ric pipel ined e xecution unit.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_06.fm.(1.2) March 27, 2006 Instruction Timing Page 213 o f 377 The inst ruction pi peli ne stages are descr ibed as follows: •.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor In str ucti on T imi ng Page 214 of 377 gx_06.fm.(1.2) March 27, 2006 The nota tion conv ention s used i n the ins truction timing ex amples are as fo llows: Figure 6- 3 shows the stages of the 750GX’s e xecution units .
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_06.fm.(1.2) March 27, 2006 Instruction Timing Page 215 o f 377 6.3 Timing Considerations The 7 50GX is a supers calar pro cessor.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor In str ucti on T imi ng Page 216 of 377 gx_06.fm.(1.2) March 27, 2006 The 750GX’s in structi on-cache throttlin g feature, manage d.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_06.fm.(1.2) March 27, 2006 Instruction Timing Page 217 o f 377 6.3.2.1 Cache Arb itratio n When th e instru ction fetc her request s ins truction s from the i nstruct ion cach e, two thin gs might h appe n.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor In str ucti on T imi ng Page 218 of 377 gx_06.fm.(1.2) March 27, 2006 Figure 6-4. Instruct ion Flow Di agram SRU IU2 FPU Complete (Re.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_06.fm.(1.2) March 27, 2006 Instruction Timing Page 219 o f 377 Figure 6- 5 on page 220 shows a s imple exam ple of instruc tion fetc hing that h its in th e L1 ca che.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor In str ucti on T imi ng Page 220 of 377 gx_06.fm.(1.2) March 27, 2006 Figure 6-5. Instructio n Timing—C ache Hit 6 fadd 1 fadd 0 ad.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_06.fm.(1.2) March 27, 2006 Instruction Timing Page 221 o f 377 The instr uction ti ming for this ex ample is des cribe d cycle-by- cycle as follows : 1. In cycle 0 , inst ructions 0 –3 are fetched from the in structi on ca che.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor In str ucti on T imi ng Page 222 of 377 gx_06.fm.(1.2) March 27, 2006 10. In cycle 9 , inst ruction 1 1 comple tes, ins truction 12 co ntinues th rough the FPU p ipeline , and in structi ons 13 and 14 a re dispatc hed.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_06.fm.(1.2) March 27, 2006 Instruction Timing Page 223 o f 377 Figure 6-6. Instruc tion Timing—C ache M iss 6 fadd * 7 fadd * .
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor In str ucti on T imi ng Page 224 of 377 gx_06.fm.(1.2) March 27, 2006 6.3.2.4 L2 Cach e Access Timing Co nsideratio ns If an inst ruction fetch miss es both the BTIC and the L1 ins truction c ache, the 750GX ne xt look s in the L 2 cache.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_06.fm.(1.2) March 27, 2006 Instruction Timing Page 225 o f 377 When t he dispat ch unit di spatches a n instr uction to its exec ution uni t, it allo cates a Re name Re gister (o r registe rs) for t he resul ts of that i nstruc tion.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor In str ucti on T imi ng Page 226 of 377 gx_06.fm.(1.2) March 27, 2006 Perfor mance feat ures su ch as br anch fol ding, BT IC, dynami.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_06.fm.(1.2) March 27, 2006 Instruction Timing Page 227 o f 377 Figure 6- 8 shows the remov al of fa ll-throug h branch instru ctions, wh ich occ urs when a branch is not tak en or is pred icted as not taken .
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor In str ucti on T imi ng Page 228 of 377 gx_06.fm.(1.2) March 27, 2006 In this ex ample, th e Branch Co nditio nal ( bc ) instr uction i s encod ed to decr ement the CTR. It is predict ed as not- tak en in c lock cycle 0.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_06.fm.(1.2) March 27, 2006 Instruction Timing Page 229 o f 377 does not w rite b ack its r esults t o the ar chitec ted regist ers. In stead, it s talls i n the com pletio n queue .
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor In str ucti on T imi ng Page 230 of 377 gx_06.fm.(1.2) March 27, 2006 Predic ted Bran ch Timin g Exam ples Figure 6- 10 on page 231 shows ca ses wh ere branch instru ctions ar e predic ted.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_06.fm.(1.2) March 27, 2006 Instruction Timing Page 231 o f 377 1. During cloc k cycle 0, ins tructi ons 0 and 1 are dis patched to their res pective executio n units. Instruc tion 2 is a bran ch instru ction that updates the CT R.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor In str ucti on T imi ng Page 232 of 377 gx_06.fm.(1.2) March 27, 2006 2. In clock c ycle 1, instruc tions 2 and 3 enter the dis patch entrie s in the IQ . Instru ction 4 ( a secon d bc instruc tion) a nd 5 are fe tched.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_06.fm.(1.2) March 27, 2006 Instruction Timing Page 233 o f 377 6.4.5 L oad/Store Unit E xecution Timing The exe cution of most load -and-st ore instr uctions is pipe lined. The L SU has two pipel ine stage s.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor In str ucti on T imi ng Page 234 of 377 gx_06.fm.(1.2) March 27, 2006 6.4.7 Integer Store Gathering The 750GX perform s store gatheri ng for write- through operatio ns to nong uarded s pace.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_06.fm.(1.2) March 27, 2006 Instruction Timing Page 235 o f 377 6.5 Memory Performance Considerations Beca use the 750GX c an have a maximu m instr uction t hroug hput of thr ee inst ruction s per c lock cy cle, lac k of memory bandwidt h can affect performa nce.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor In str ucti on T imi ng Page 236 of 377 gx_06.fm.(1.2) March 27, 2006 6.5.2 Effect of TL B Miss If a page-ad dress tran slation i s not in a tra nslation lookaside bu ffer (TLB) , the 750GX hardware se arches the page table s and updates th e TLB when a transla tion is fo und.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_06.fm.(1.2) March 27, 2006 Instruction Timing Page 237 o f 377 6.6.1 Branch, Dispatch, and Completion-Unit Resource Requirement .
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor In str ucti on T imi ng Page 238 of 377 gx_06.fm.(1.2) March 27, 2006 • Requirem ents for com pleting a n instru ction from CQ1: – Instructio n in CQ0 must comp lete in s ame cycle .
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_06.fm.(1.2) March 27, 2006 Instruction Timing Page 239 o f 377 Move-from Spe cial Purpose Register mfspr (data block-addre ss tr.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor In str ucti on T imi ng Page 240 of 377 gx_06.fm.(1.2) March 27, 2006 Table 6 -6 list s condit ion r egiste r logica l instr uction latenc ies. Table 6 -7 shows in teger instruc tion late ncies.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_06.fm.(1.2) March 27, 2006 Instruction Timing Page 241 o f 377 AND Immediate Shifted andis.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor In str ucti on T imi ng Page 242 of 377 gx_06.fm.(1.2) March 27, 2006 Table 6 -8 shows la tencie s for float ing-poin t ins truction s. Pipel ined floa ting- point instr uctions are show n with the number of cloc ks in e ach pipelin e stag e separated by dashe s.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_06.fm.(1.2) March 27, 2006 Instruction Timing Page 243 o f 377 Floating Multiply- Subtract Single fmsubs [ . ] 59 28 FPU 1-1-1 — Floating Multiply- Subtract fmsub [ . ] 63 28 FPU 2-1-1 — Floating Multiply Single fm uls [ .
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor In str ucti on T imi ng Page 244 of 377 gx_06.fm.(1.2) March 27, 2006 Table 6 -9 shows l oad-and-s tore ins truction latencies . Pipeli ned loa d/store i nstruct ions are sho wn with cy cles of total la tency an d through put cycles separa ted by a c olon.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_06.fm.(1.2) March 27, 2006 Instruction Timing Page 245 o f 377 Load Floating-Point Single Indexed lfsx 31 535 LS U 2:1 — Load .
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor In str ucti on T imi ng Page 246 of 377 gx_06.fm.(1.2) March 27, 2006 Store Floating-Point Double stfd 54 — LSU 2:1 — Store Float.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_06.fm.(1.2) March 27, 2006 Instruction Timing Page 247 o f 377 Store Word with Update Indexed stwux 31 183 LS U 2:1 — Store Word I ndexed stwx 31 151 LS U 2:1 — TLB Invalidate Entry tlbie 31 306 LSU 3:4 1 Execution T able 6-9.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor In str ucti on T imi ng Page 248 of 377 gx_06.fm.(1.2) March 27, 2006.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_07.fm.(1.2) March 27, 2006 Signal Descriptions Page 249 o f 377 7. Signal Descriptions This cha pter d escribes the 750G X micropr ocess or’s externa l signa ls.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Signal Descriptions Page 250 of 377 gx_07.fm.(1.2) March 27, 2006 7.1 Signal Configuration Figure 7- 1 illustr ates the 7 50GX’s signal config uration, sh owing h ow the sig nals ar e grouped .
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_07.fm.(1.2) March 27, 2006 Signal Descriptions Page 251 o f 377 7.2 Signal Descriptions This sec tion sum marizes th e func tions of i ndividual signa ls on the 750GX, g rouped ac cording to Figure 7-1 .
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Signal Descriptions Page 252 of 377 gx_07.fm.(1.2) March 27, 2006 7.2.1.2 Bus Gra nt (BG )—Input 7.2.1.3 Address Bu s Busy (ABB ) The addres s bus b usy (ABB ) signa l is both an inpu t and an o utput s ignal.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_07.fm.(1.2) March 27, 2006 Signal Descriptions Page 253 o f 377 Addres s Bus B usy (A BB ) — Input 7.2.2 Address T ransfer Start Signals Addres s trans fer start s ignals a re in put and out put signa ls tha t indicat e that a n addres s-bus t ransfer has begun.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Signal Descriptions Page 254 of 377 gx_07.fm.(1.2) March 27, 2006 7.2. 3 Addr ess T ran sfer Sig nals The addres s transfer signal s are used to trans mit the add ress a nd to gener ate and mo nitor parity for the address transfe r.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_07.fm.(1.2) March 27, 2006 Signal Descriptions Page 255 o f 377 7.2.3.2 Addres s-Bus Pari ty (AP[ 0–3]) The a ddress-b us pari.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Signal Descriptions Page 256 of 377 gx_07.fm.(1.2) March 27, 2006 7.2.4.1 Transfe r T ype (TT[0–4]) The transfe r type (TT [0–4]) sig nals cons ist of five i nput/out put signals on the 750GX .
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_07.fm.(1.2) March 27, 2006 Signal Descriptions Page 257 o f 377 Table 7 -2 describe s the 6 0x bus spec ificati on trans fer enco dings and the 750 GX bus snoop respons e on an address h it.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Signal Descriptions Page 258 of 377 gx_07.fm.(1.2) March 27, 2006 7.2.4.2 Transfer Size (TS IZ [0–2] ) —O utpu t eieio Addres s o.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_07.fm.(1.2) March 27, 2006 Signal Descriptions Page 259 o f 377 7.2.4.3 Transfer Burst (TBST ) The tra nsfer burs t (TBST ) signal i s an inp ut/outpu t signal on t he 750G X.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Signal Descriptions Page 260 of 377 gx_07.fm.(1.2) March 27, 2006 7.2.4.4 Cache In hibit (CI )—Output The cach e inhib it (CI ) signal i s an outpu t signal on the 7 50GX. 7.2.4.5 Wri te-Through (WT )—Outpu t The write- through (WT ) signa l is an output s ignal on the 750GX .
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_07.fm.(1.2) March 27, 2006 Signal Descriptions Page 261 o f 377 7.2.4.6 Global (G BL ) The glo bal (GBL ) s ignal is an input/ output sig nal on the 750GX.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Signal Descriptions Page 262 of 377 gx_07.fm.(1.2) March 27, 2006 7.2.5 Address T ransf er T er mination Signals The addres s transfe.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_07.fm.(1.2) March 27, 2006 Signal Descriptions Page 263 o f 377 7.2.5.2 Addres s Retry (ARTRY ) The addres s retry (ARTRY ) si gnal is b oth an inp ut and o utput sign al on the 750GX .
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Signal Descriptions Page 264 of 377 gx_07.fm.(1.2) March 27, 2006 Addres s Retr y (ARTR Y )—Input 7.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_07.fm.(1.2) March 27, 2006 Signal Descriptions Page 265 o f 377 7.2.6.2 Data-Bus Write-O nly (DBWO ) The data- bu s wri te- onl y (D BWO ) signal is an input- only s ignal on t he 750G X.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Signal Descriptions Page 266 of 377 gx_07.fm.(1.2) March 27, 2006 Data Bu s Busy (D BB )—Input 7.2.7 Data-T r ansfer S igna ls Like the address transfe r signa ls, the da ta-transfer signal s are used to trans mit data an d to gen erate and monitor parity f or the data transfe r.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_07.fm.(1.2) March 27, 2006 Signal Descriptions Page 267 o f 377 Data Bus (DH[ 0–31], DL[0–3 1])—Outp ut Data Bus (DH[ 0–31], DL[0–3 1])—In put 7.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Signal Descriptions Page 268 of 377 gx_07.fm.(1.2) March 27, 2006 Data-Bus Pa rity (DP[ 0–7])— Input 7.2.7.3 Data Bus Disable (DBDIS )—Input 7.2.8 Data-T r ansfer T ermi nation Signals Data termi nation s ignals a re requir ed after e ach data b eat in a da ta transfe r.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_07.fm.(1.2) March 27, 2006 Signal Descriptions Page 269 o f 377 7.2.8.2 Data Retr y (DRTRY )—Input 7.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Signal Descriptions Page 270 of 377 gx_07.fm.(1.2) March 27, 2006 7.2.9 System St atus Signals Most sy stem stat us signa ls are inp ut signal s that indicate when exc eptions a re receiv ed, whe n checkst op conditio ns have occu rred, and whe n the 75 0GX mus t be res et.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_07.fm.(1.2) March 27, 2006 Signal Descriptions Page 271 o f 377 7.2.9.3 Machin e-Check Interrupt ( MCP )—Input 7.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Signal Descriptions Page 272 of 377 gx_07.fm.(1.2) March 27, 2006 7.2.10 Reset Sig nals There ar e two rese t signal s on th e 750GX— hard re set (HRESET ) a nd soft r eset (SRESET ).
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_07.fm.(1.2) March 27, 2006 Signal Descriptions Page 273 o f 377 7.2.1 1 Pro cessor Status Signals Process or status signal s indic ate the sta te of the proces sor.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Signal Descriptions Page 274 of 377 gx_07.fm.(1.2) March 27, 2006 7.2.1 1.4 Time Base Enable (TBEN)—Input 7.2.1 1.5 TLB Invalidate Synchronize (TLBISYNC )—Input The TLB In vali date Sync hroniz e (TLBIS YNC ) s ignal i s an input-o nly signal.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_07.fm.(1.2) March 27, 2006 Signal Descriptions Page 275 o f 377 7.2.13 I/O V oltage Select Sign als Table 7 -7 shows the settings for the I/ O vo ltage sig nals.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Signal Descriptions Page 276 of 377 gx_07.fm.(1.2) March 27, 2006 7.2.14.3 L1_TS TCLK 7.2.14.4 L2_TS TCLK 7.2.14.5 BVSE L 7.2.15 Clock Sign als The 750 GX requ ires a s ingle s ystem c lock inpu t (SYS CLK).
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_07.fm.(1.2) March 27, 2006 Signal Descriptions Page 277 o f 377 7.2.15.1 System Clock (SYSCLK)—Input The 750G X requires a single syst em clock (SYSCLK) i nput. This inpu t sets the frequency of operatio n for the bus interfa ce.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Signal Descriptions Page 278 of 377 gx_07.fm.(1.2) March 27, 2006 7.2.15.4 PLL Range (PLL_RNG[0:1])—Input 7.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_08.fm.(1.2) March 27, 2006 Bus Interface Operation Page 279 o f 377 8. Bus Interface Operat ion This cha pter desc ribes the PowerPC 750GX mi croproc essor’s bus inter face and its oper ation.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Bus Interface Operation Page 280 of 377 gx_08.fm.(1.2) March 27, 2006 8.1 B us Interfac e Overvie w The bus interface p riori tizes r.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_08.fm.(1.2) March 27, 2006 Bus Interface Operation Page 281 o f 377 In additio n to the loads, s tores, and i nstruc tion fetch .
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Bus Interface Operation Page 282 of 377 gx_08.fm.(1.2) March 27, 2006 Cache li nes are selected for replac ement bas ed on a pseudo l east-rec ently-use d (PLRU) al gorithm. Each time a cache li ne is access ed, it is tagged as the most-rec ently- used line of the se t.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_08.fm.(1.2) March 27, 2006 Bus Interface Operation Page 283 o f 377 one, two, or eight bea ts dep ending on the size of the p rogram transactio n and th e cache mod e for t he address .
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Bus Interface Operation Page 284 of 377 gx_08.fm.(1.2) March 27, 2006 8.2 M em ory-Ac ce ss Prot ocol Memory accesses are d ivided i nto addr ess and data tenures. Each te nure has three phases —bus ar bitration, transfer, a nd termi nation.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_08.fm.(1.2) March 27, 2006 Bus Interface Operation Page 285 o f 377 Data tenur e: The 750G X generate s an a ddress-o nly bus tr.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Bus Interface Operation Page 286 of 377 gx_08.fm.(1.2) March 27, 2006 8.2.2 Miss-under-Miss To improv e proce ssor p erforma nce, a f.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_08.fm.(1.2) March 27, 2006 Bus Interface Operation Page 287 o f 377 data cac he. If ther e is a m iss in the L2 cache , then t he request i s pass ed on to th e bus interfac e unit ( BIU) via three add itional L 2-to-B IU reload-r equest qu eues.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Bus Interface Operation Page 288 of 377 gx_08.fm.(1.2) March 27, 2006 The BIU has both AR buffers and a 4-deep relo ad-requ est queue.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_08.fm.(1.2) March 27, 2006 Bus Interface Operation Page 289 o f 377 Load mu ltiple a nd load s tring in structions allow on e MuM ( two outsta nding miss requ ests) to pipelin e on the 60x bu s.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Bus Interface Operation Page 290 of 377 gx_08.fm.(1.2) March 27, 2006 8.2.2.2 Speculative Loads and Conditional Branches Loads tha t are d ispatch ed before a preced ing cond itiona l branc h is resol ved are specula tive.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_08.fm.(1.2) March 27, 2006 Bus Interface Operation Page 291 o f 377 Externa l arbiters must al low only one devi ce at a tim e to be the addre ss-bus m aste r.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Bus Interface Operation Page 292 of 377 gx_08.fm.(1.2) March 27, 2006 System designer s shoul d note that it is pos sible t o ignore the ABB s ignal, a nd regene rate the s tate of AB B loca lly within each dev ice by mon itoring th e TS and AACK inp ut signals.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_08.fm.(1.2) March 27, 2006 Bus Interface Operation Page 293 o f 377 Figur e 8-8.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Bus Interface Operation Page 294 of 377 gx_08.fm.(1.2) March 27, 2006 8.3.2.1 Addres s-Bus Pari ty The 750GX always generates 1 bit of c orrect od d-byte par ity for eac h of the 4 bytes o f addres s when a valid address is on th e bus.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_08.fm.(1.2) March 27, 2006 Bus Interface Operation Page 295 o f 377 The bas ic cohere ncy si ze of the bu s is def ined to be 32 b ytes (cor respon ding to one cac he line).
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Bus Interface Operation Page 296 of 377 gx_08.fm.(1.2) March 27, 2006 8.3.2.4 Effect of Align ment in Dat a Transfers Table 8 -4 lists the align ed trans fers that ca n occur on the 750 GX bus.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_08.fm.(1.2) March 27, 2006 Bus Interface Operation Page 297 o f 377 The 7 50GX suppo rts misal igned mem ory ope rations, althou gh their use can sub stantial ly degr ade perfor- mance.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Bus Interface Operation Page 298 of 377 gx_08.fm.(1.2) March 27, 2006 Effect of Align ment in Data T ransfers (32-Bi t Bus) The aligne d data-tr ansfer cas es for 32- bit data-bus mode are shown i n Table 8-6 on page 298.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_08.fm.(1.2) March 27, 2006 Bus Interface Operation Page 299 o f 377 Misali gned da ta transf ers when the 750GX is con figur ed .
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Bus Interface Operation Page 300 of 377 gx_08.fm.(1.2) March 27, 2006 8.3.2.5 Alignment of External Control Instructions The size o f the data tr ansfer ass ociated with th e eciwx an d ecowx instru ctions is a lways 4 bytes.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_08.fm.(1.2) March 27, 2006 Bus Interface Operation Page 301 o f 377 address tenures occur un til the cu rrent s noop pu sh from the 750GX is com pleted.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Bus Interface Operation Page 302 of 377 gx_08.fm.(1.2) March 27, 2006 A qualif ied dat a-bus g rant can b e expre ssed as the follow ing: QDBG = DBG asserted wh ile DBB , DRTRY , and ARTRY (as sociat ed with the data-bus operatio n) are negated.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_08.fm.(1.2) March 27, 2006 Bus Interface Operation Page 303 o f 377 8.4.2 Data-Bus W rite-Only As a re sult of ad dress p ipelini ng, the 7 50GX can h ave up to t wo data t enure s queued t o perfor m when it receiv es a quali fied DBG .
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Bus Interface Operation Page 304 of 377 gx_08.fm.(1.2) March 27, 2006 (or only) data bea t, the 75 0GX nega tes DBB b ut still conside rs the da ta beat active a nd waits fo r another assert ion of TA .
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_08.fm.(1.2) March 27, 2006 Bus Interface Operation Page 305 o f 377 Normal te rmination o f a burst transfer o ccurs whe n TA is a sserted for four bus clock cycl es, as shown in Figure 8- 13 .
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Bus Interface Operation Page 306 of 377 gx_08.fm.(1.2) March 27, 2006 For read bursts, DRT RY can b e asserted one bus clock c ycle a.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_08.fm.(1.2) March 27, 2006 Bus Interface Operation Page 307 o f 377 Figure 8- 15 show s the eff ect o f using DRT RY dur ing a bu rst re ad. It al so show s the effect o f usi ng TA to pace the data- transfer rate.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Bus Interface Operation Page 308 of 377 gx_08.fm.(1.2) March 27, 2006 Note: T EA generate s a ma chine- check e xception depend ing on MS R[ME].
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_08.fm.(1.2) March 27, 2006 Bus Interface Operation Page 309 o f 377 8.5 Tim ing Examples This s ection s hows t iming di agrams f or va rious sc enarios . Figu re 8- 17 on page 310 illus trates th e fastest single- beat rea ds poss ible for the 750GX .
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Bus Interface Operation Page 310 of 377 gx_08.fm.(1.2) March 27, 2006 Figure 8-17. Fastest S ingle-B eat Reads BR BG ABB TS A[0–31].
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_08.fm.(1.2) March 27, 2006 Bus Interface Operation Page 311 o f 377 Figure 8- 18 illu strates the fastes t single -beat writes sup ported by the 75 0GX. Al l bidirect ional signals are tristate d between bu s tenu res.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Bus Interface Operation Page 312 of 377 gx_08.fm.(1.2) March 27, 2006 Figure 8- 19 shows three way s to del ay single- beat rea ds using data-del ay control s: • The TA sign al can r emain neg ated to insert w ait states in cloc k cyc les 3 and 4.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_08.fm.(1.2) March 27, 2006 Bus Interface Operation Page 313 o f 377 Figure 8- 20 shows data-del ay contro ls in a s ingle- beat write operatio n. Note th at all bi directiona l signal s are tristate d between bu s tenu res.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Bus Interface Operation Page 314 of 377 gx_08.fm.(1.2) March 27, 2006 Figure 8- 21 shows the use o f data-del ay control s wit h burst tra nsfers. Note that all bidi rectional signals are tristate d bet ween bus tenure s.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_08.fm.(1.2) March 27, 2006 Bus Interface Operation Page 315 o f 377 Figure 8- 22 shows the use o f the TEA signal . Note that al l bid irectio nal signal s are tr istated b etween b us tenures .
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Bus Interface Operation Page 316 of 377 gx_08.fm.(1.2) March 27, 2006 8.6 Option al Bus Configur ation The 750G X supports optional bu s conf iguratio ns that are selected during the negation of th e HRESE T signal .
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_08.fm.(1.2) March 27, 2006 Bus Interface Operation Page 317 o f 377 An examp le of a two- beat data transfer ( with DRTRY asserted during e ach data te nure) is shown in Figure 8- 24 .
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Bus Interface Operation Page 318 of 377 gx_08.fm.(1.2) March 27, 2006 The 750GX selec ts 64-b it or 32- bit data bu s mode at startup by sampli ng the st ate of the TLBIS YNC signa l at the negati on of HRESE T .
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_08.fm.(1.2) March 27, 2006 Bus Interface Operation Page 319 o f 377 8.7 Proce ssor S t ate S ignals This se ction desc ribes the 750GX's su pport for atom ic update and memory throug h the use of the lwar x and stwcx.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Bus Interface Operation Page 320 of 377 gx_08.fm.(1.2) March 27, 2006 8.9 Using Dat a-Bus Write-Only The 750G X supports split-t ransac tion pip elined tra nsact ions.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_08.fm.(1.2) March 27, 2006 Bus Interface Operation Page 321 o f 377 Note that al though the 750GX can pipe line any wr ite trans action b ehind the read trans action, s pecial c are should b e used when usin g the en veloped write feat ure.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Bus Interface Operation Page 322 of 377 gx_08.fm.(1.2) March 27, 2006.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_09.fm.(1.2) March 27, 2006 L2 Cache Page 323 o f 377 9. L2 Cache Thi s chapt er de scri bes th e 750G X micr opro cess or‘s implem enta tion of the 1-MB L2 cach e. Note: The L2 c ache is initial ly disa bled fo llowing a power-o n or hard r eset.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor L2 Cache Page 324 of 377 gx_09.fm.(1.2) March 27, 2006 If mult iple read r equests from the L 1 caches ar e pendin g, the L 2 cache c.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_09.fm.(1.2) March 27, 2006 L2 Cache Page 325 o f 377 Wheneve r a way i n the set i s referen ced, the LRU bits ar e updated.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor L2 Cache Page 326 of 377 gx_09.fm.(1.2) March 27, 2006 110 x011 1 1x1 xxx0 3 1x1 xx01 2 101 0x11 0 111 x011 1 T able 9-3.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_09.fm.(1.2) March 27, 2006 L2 Cache Page 327 o f 377 Figure 9-1. L2 Cache 60x Bus 64-bit Bus Interface Unit Data-Out Req uest Da.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor L2 Cache Page 328 of 377 gx_09.fm.(1.2) March 27, 2006 The exec ution of th e St ore W ord Co ndit iona l Inde xed ( stwcx. ) instruct ion results in single- beat wri tes from the L1 d ata cach e.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_09.fm.(1.2) March 27, 2006 L2 Cache Page 329 o f 377 9.3 L2 Cache Control Reg ister (L2CR) The L2 Cache Co ntrol Reg ister is us ed to conf igure an d enabl e the L2 c ache.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor L2 Cache Page 330 of 377 gx_09.fm.(1.2) March 27, 2006 9.6 L2 Ca che Used as On -Chip Me mor y The L2 c ache ca n be co nfigured to b e unlo cked, par tially lock ed, or com pletely l ocked.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_09.fm.(1.2) March 27, 2006 L2 Cache Page 331 o f 377 9.6.1.1 Loading the Locked L2 Cache Contents a re loaded into t he L2 c ache simpl y by ex ecuting load inst ructions to cach eable addresses that miss i n the L1.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor L2 Cache Page 332 of 377 gx_09.fm.(1.2) March 27, 2006 The dcbz inst ruction has no effect on th e L2-cach e state, whether th e sta te is l ocked o r not. T he dcbi in stru c- tion caus es inv alidatio n of the block in th e case of an L2 h it, for bot h normal and lo cked ca ches.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_09.fm.(1.2) March 27, 2006 L2 Cache Page 333 o f 377 9.8.2 L2 Cache T e stin g A typica l test for veri fying the proper operatio n of the 750GX micropr ocessor’s L2-cac he memo ry follows this seque nce: 1.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor L2 Cache Page 334 of 377 gx_09.fm.(1.2) March 27, 2006.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_10.fm.(1.2) March 27, 2006 Power and T hermal Managemen t Page 335 o f 377 10. Power and Thermal Management The 750GX micr oproce ssor is specifi cally d esigned f or low-p ower operat ion.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Power and Thermal Management Page 336 of 377 gx_10.fm.(1.2) March 27, 2006 Figure 10-1.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_10.fm.(1.2) March 27, 2006 Power and T hermal Managemen t Page 337 o f 377 10.2.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Power and Thermal Management Page 338 of 377 gx_10.fm.(1.2) March 27, 2006 750GX wi ll then b e able respond to a sn oop cycle . Asser tion of QACK follo wing the s noop cyc le will aga in disable the 750 GX’s sno op cap ability.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_10.fm.(1.2) March 27, 2006 Power and T hermal Managemen t Page 339 o f 377 10.2.1.4 Sleep M ode Sleep mode consu mes the least am ount of powe r of the fou r modes sinc e all funct ional units are disa bled.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Power and Thermal Management Page 340 of 377 gx_10.fm.(1.2) March 27, 2006 10.2.2 Power Management Sof tware Consider at ions Since th e 750GX is a d ual-issu e process or with ou t-of-order execu tion capa bility, car e must b e taken in how the power manage ment mode i s entere d.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_10.fm.(1.2) March 27, 2006 Power and T hermal Managemen t Page 341 o f 377 Note: If the P LL softwar e con figurati on is used, suffic ient tim e must be allowed for the c hosen PL L to lo ck.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Power and Thermal Management Page 342 of 377 gx_10.fm.(1.2) March 27, 2006 10.3.3 Dual P LL Implementation Switchi ng between the two PLLs on the 750GX is intend ed to be a seaml ess, 3-cycle operati on.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_10.fm.(1.2) March 27, 2006 Power and T hermal Managemen t Page 343 o f 377 10.4 Therma l Assist Unit With the i ncreasin g power.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Power and Thermal Management Page 344 of 377 gx_10.fm.(1.2) March 27, 2006 The TAU pr ovides th ermal c ontrol by pe riodic ally co m.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_10.fm.(1.2) March 27, 2006 Power and T hermal Managemen t Page 345 o f 377 10.4.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Power and Thermal Management Page 346 of 377 gx_10.fm.(1.2) March 27, 2006 10.4.2.2 T AU Dual-Thr eshold Mode The configu ratio n and.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_10.fm.(1.2) March 27, 2006 Power and T hermal Managemen t Page 347 o f 377 10.4.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Power and Thermal Management Page 348 of 377 gx_10.fm.(1.2) March 27, 2006 The bit field set tings of th e ICTC SPR are shown in Table 10- 4 on page 348. T able 10-4. ICTC Bit Fi eld Settings Bits Nam e Description 0-22 Res erved Bits reserved fo r future use.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_11.fm.(1.2) March 27, 2006 Performance Monitor and System Related Features Page 349 o f 377 1 1.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Performance Monitor and Syst em Related Features Page 350 of 377 gx_11.fm.(1.2) March 27, 2006 As a re sult of a per formance- monitor exception b eing ta ken, th e action t aken depe nds on the program mable events.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_11.fm.(1.2) March 27, 2006 Performance Monitor and System Related Features Page 351 o f 377 1 1.2.1 Performance-Monitor Registers Thi s sectio n desc ribe s the r egis ter s used b y the perfo rmanc e mo nitor .
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Performance Monitor and Syst em Related Features Page 352 of 377 gx_11.fm.(1.2) March 27, 2006 Software is expecte d to us e the mtspr instruc tion to ex plicitl y set P MC to nonov erflowed value s.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_11.fm.(1.2) March 27, 2006 Performance Monitor and System Related Features Page 353 o f 377 Bits MM CR1[0:4] spe cify events associa ted with PM C3, as sh own in T able 11-4 . 00 0101 C ounts L1 instruction-cache miss es.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Performance Monitor and Syst em Related Features Page 354 of 377 gx_11.fm.(1.2) March 27, 2006 Bits MM CR1[5:9] spe cify events associa ted with PM C4, as sh own in T able 11-5 .
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_11.fm.(1.2) March 27, 2006 Performance Monitor and System Related Features Page 355 o f 377 1 1.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Performance Monitor and Syst em Related Features Page 356 of 377 gx_11.fm.(1.2) March 27, 2006 1 1.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_11.fm.(1.2) March 27, 2006 Performance Monitor and System Related Features Page 357 o f 377 1 1.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Performance Monitor and Syst em Related Features Page 358 of 377 gx_11.fm.(1.2) March 27, 2006 • Internal registe rs (such as the g.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_11.fm.(1.2) March 27, 2006 Performance Monitor and System Related Features Page 359 o f 377 11 . 8 R e s e ts The 750GX support s two ty pes of r esets: a hard and a soft reset . 1 1.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Performance Monitor and Syst em Related Features Page 360 of 377 gx_11.fm.(1.2) March 27, 2006 1 1.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_11.fm.(1.2) March 27, 2006 Performance Monitor and System Related Features Page 361 o f 377 1 1.9 Checkst op s A check stop ca uses the proces sor to ha lt and ass ert the c heckstop output p in, CKST P_OUT .
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Performance Monitor and Syst em Related Features Page 362 of 377 gx_11.fm.(1.2) March 27, 2006 Table 1 1-7 shows th e contro l bits for H ID2. The che ckstop inp ut pin (CK STP_IN ) a lways c auses a checkstop regardl ess of t he state of the MSR[ME ] bi t.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_11.fm.(1.2) March 27, 2006 Performance Monitor and System Related Features Page 363 o f 377 1 1.10 750GX Parity Parity is impleme nted for t he foll owing ar rays: ins truction cach e, instruc tion ta g, data cac he, data ta g, and L2 tag.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Performance Monitor and Syst em Related Features Page 364 of 377 gx_11.fm.(1.2) March 27, 2006 1 1.10.1 P arity Control and S tatus Parity is enabled with the Hardware- Implementa tion-Depe ndent Regis ter 2 ( HID2).
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_acronyms.fm .(1.2) March 27, 2006 Acronyms and Abbreviations Page 365 o f 377 Acronyms and Abbreviations BAT block -addre ss tra.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Acronyms a nd Abbreviations Page 366 of 377 gx_acronyms.fm.(1. 2) March 27, 2006 FPR Fl oati ng Po int Reg ister FPSCR F loating-Po i.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_acronyms.fm .(1.2) March 27, 2006 Acronyms and Abbreviations Page 367 o f 377 NaN not a n umber no-op no operation OEA ope ratin.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Acronyms a nd Abbreviations Page 368 of 377 gx_acronyms.fm.(1. 2) March 27, 2006 THRM n T hermal-Ma nagement Re giste rs TLB trans la.
User’s Ma nua l IBM Po werP C 750G X and 75 0GL R I SC Mi crop roce ssor 750gx_umIX.fm.(1.2) March 27, 2006 Index Page 369 o f 377 Index A AACK (add ress acknowl edge) sig nal , 262 ABB (addres s bu.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Index Page 370 of 377 750gx_umIX.fm.(1.2) March 27, 2006 L2 interface cache g lobal invalida tion , 329 cache i nitial ization , 329 cach e test ing , 333 dcbi , 328 eieio , 328 operation , 323 stwcx.
User’s Ma nua l IBM Po werP C 750G X and 75 0GL R I SC Mi crop roce ssor 750gx_umIX.fm.(1.2) March 27, 2006 Index Page 371 o f 377 register s ettings MSR , 162 SRR0/SRR1 , 156 rese t exce ptio n , 1.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Index Page 372 of 377 750gx_umIX.fm.(1.2) March 27, 2006 integer , 99 byte revers e instruc tion s , 102 floating -point mov e , 98 f.
User’s Ma nua l IBM Po werP C 750G X and 75 0GL R I SC Mi crop roce ssor 750gx_umIX.fm.(1.2) March 27, 2006 Index Page 373 o f 377 O OEA exceptio n mec hanism , 151 memory m anage ment spe cific ati.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Index Page 374 of 377 750gx_umIX.fm.(1.2) March 27, 2006 DABR , 62 DAR , 61 DEC , 62 DSISR , 61 EAR , 62 HID0 , 65 , 337 HID1 , 70 IA.
User’s Ma nua l IBM Po werP C 750G X and 75 0GL R I SC Mi crop roce ssor 750gx_umIX.fm.(1.2) March 27, 2006 Index Page 375 o f 377 Stal l, def ini tion , 21 1 Stat ic br anch pr edic tio n , 216 , 229 stwcx.
User’s M anual IBM PowerP C 750GX and 750GL RISC Micropr ocessor Index Page 376 of 377 750gx_umIX.fm.(1.2) March 27, 2006.
User’s Ma nua l IBM Pow erPC 750GX an d 750GL RISC Microproces sor gx_revlog.fm.(1.2) March 27, 2006 Revision Log Page 377 o f 377 Revision Log Revision Date Contents of Modification February 27, 2004 Initial release (version 1.0) September 30, 2 004 (version 1.
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