(CSAPP第三版系列)导航篇传送门
4.46
A. 这段代码序列没有正确描述指令popq %rsp的行为。该段代码序列使%rsp的值为(%rsp)+8,而指令popq%rsp执行后,%rsp的值应为(%rsp)。
B. 改写代码序列:
addq $8 , %rsp
movq-8(%rsp) , REG4.48
冒泡排序函数的测试和交换(6-11行)代码:
if(data[i+1] < data[i]){ /*Swap adjacent elements*/ long t = data[i+1]; data[i+1] = data[i]; data[i] = t; }对应的Y86-64代码修改为条件转移,代码如下:
mrmovq (%rdx), %r8 rrmovq %rdx, %rsi addq %r10, %rsi mrmovq (%rsi), %rcx rrmovq %rcx, %r10 subq %r8, %r10 rrmovq %rcx, %r10 cmovl %r8, %r10 rmmovq %r10, (%rsi) rrmovq %r8, %r10 cmovl %rcx, %r10 rmmovq %r10, (%rdx)
4.50
Y86-64代码如下:
# Execution begins at address 0 .pos 0 irmovq stack, %rsp # Set up stack pointer call main # Execute main program halt # Terminate program # Array of 8 elements .align 8 vals: .quad 0x000000000000 .quad 0x000000000000 .quad 0x000000000000 .quad 0x000000000000 .quad 0x000000000000 .quad 0x000000000000 .quad 0x000000000000 .quad 0x000000000000 jump_table: .quad L1 .quad L4 .quad L2 .quad L3 .quad L4 .quad L2 main: irmovq vals, %r12 irmovq $-1,%rdi call switchv rmmovq %rax, (%r12) irmovq $0,%rdi call switchv rmmovq %rax, 0x8(%r12) irmovq $1,%rdi call switchv rmmovq %rax, 0x10(%r12) irmovq $2,%rdi call switchv rmmovq %rax, 0x18(%r12) irmovq $3,%rdi call switchv rmmovq %rax, 0x20(%r12) irmovq $4,%rdi call switchv rmmovq %rax, 0x28(%r12) irmovq $5,%rdi call switchv rmmovq %rax, 0x30(%r12) irmovq $6,%rdi call switchv rmmovq %rax, 0x38(%r12) ret # long switchv(long idx) # idx in %rdi switchv: rrmovq %rdi, %r8 irmovq $5, %r9 subq %r9, %r8 jg L4 andq %rdi, %rdi jl L4 irmovq jump_table, %r8 irmovq $8, %r9 irmovq $1, %r10 loop: subq %r10, %rdi jl endloop addq %r9, %r8 jmp loop endloop: mrmovq (%r8), %r8 pushq %r8 ret L1: irmovq 0xaaa, %rax ret L2: irmovq 0xbbb, %rax ret L3: irmovq 0xccc, %rax ret L4: irmovq 0xddd, %rax #default ret # Stack starts here and grows to lower addresses .pos 0x300 #栈开始地址不能太小 stack:测试结果截图:
4.52
设计思想:
分析seq-full.hcl,需要对Instr_valid, need_regids, need_valC, srcB, dstE, aluA, aluB进行修改。
bool Instr_valid = icode in{…}; 大括号中所列指令需加上IIADDQ
bool need_regids = icode in{…}; 大括号中所列指令需加上IIADDQ
bool need_valC = icode in{…}; 大括号中所列指令需加上IIADDQ
word srcB = [
icode in {…} : rB; 大括号中所列指令需加上IIADDQ
…
];
word dstE = [
…
icode in {…} : rB; 大括号中所列指令需加上IIADDQ
…
];
word aluA = [
…
icode in {… } : valC; 大括号中所列指令需加上IIADDQ
…
];
word aluB = [
icode in { … } : valB; 大括号中所列指令需加上IIADDQ
…
];添加IIADDQ指令后seq-full.hcl文件:
#/* $begin seq-all-hcl */ #################################################################### # HCL Description of Control for Single Cycle Y86-64 Processor SEQ # # Copyright (C) Randal E. Bryant, David R. O'Hallaron, 2010 # #################################################################### ## Your task is to implement the iaddq instruction ## The file contains a declaration of the icodes ## for iaddq (IIADDQ) ## Your job is to add the rest of the logic to make it work #################################################################### # C Include's. Don't alter these # #################################################################### quote '#include <stdio.h>' quote '#include "isa.h"' quote '#include "sim.h"' quote 'int sim_main(int argc, char *argv[]);' quote 'word_t gen_pc(){return 0;}' quote 'int main(int argc, char *argv[])' quote ' {plusmode=0;return sim_main(argc,argv);}' #################################################################### # Declarations. Do not change/remove/delete any of these # #################################################################### ##### Symbolic representation of Y86-64 Instruction Codes ############# wordsig INOP 'I_NOP' wordsig IHALT 'I_HALT' wordsig IRRMOVQ 'I_RRMOVQ' wordsig IIRMOVQ 'I_IRMOVQ' wordsig IRMMOVQ 'I_RMMOVQ' wordsig IMRMOVQ 'I_MRMOVQ' wordsig IOPQ 'I_ALU' wordsig IJXX 'I_JMP' wordsig ICALL 'I_CALL' wordsig IRET 'I_RET' wordsig IPUSHQ 'I_PUSHQ' wordsig IPOPQ 'I_POPQ' # Instruction code for iaddq instruction wordsig IIADDQ 'I_IADDQ' ##### Symbolic represenations of Y86-64 function codes ##### wordsig FNONE 'F_NONE' # Default function code ##### Symbolic representation of Y86-64 Registers referenced explicitly ##### wordsig RRSP 'REG_RSP' # Stack Pointer wordsig RNONE 'REG_NONE' # Special value indicating "no register" ##### ALU Functions referenced explicitly ##### wordsig ALUADD 'A_ADD' # ALU should add its arguments ##### Possible instruction status values ##### wordsig SAOK 'STAT_AOK' # Normal execution wordsig SADR 'STAT_ADR' # Invalid memory address wordsig SINS 'STAT_INS' # Invalid instruction wordsig SHLT 'STAT_HLT' # Halt instruction encountered ##### Signals that can be referenced by control logic #################### ##### Fetch stage inputs ##### wordsig pc 'pc' # Program counter ##### Fetch stage computations ##### wordsig imem_icode 'imem_icode' # icode field from instruction memory wordsig imem_ifun 'imem_ifun' # ifun field from instruction memory wordsig icode 'icode' # Instruction control code wordsig ifun 'ifun' # Instruction function wordsig rA 'ra' # rA field from instruction wordsig rB 'rb' # rB field from instruction wordsig valC 'valc' # Constant from instruction wordsig valP 'valp' # Address of following instruction boolsig imem_error 'imem_error' # Error signal from instruction memory boolsig instr_valid 'instr_valid' # Is fetched instruction valid? ##### Decode stage computations ##### wordsig valA 'vala' # Value from register A port wordsig valB 'valb' # Value from register B port ##### Execute stage computations ##### wordsig valE 'vale' # Value computed by ALU boolsig Cnd 'cond' # Branch test ##### Memory stage computations ##### wordsig valM 'valm' # Value read from memory boolsig dmem_error 'dmem_error' # Error signal from data memory #################################################################### # Control Signal Definitions. # #################################################################### ################ Fetch Stage ################################### # Determine instruction code word icode = [ imem_error: INOP; 1: imem_icode; # Default: get from instruction memory ]; # Determine instruction function word ifun = [ imem_error: FNONE; 1: imem_ifun; # Default: get from instruction memory ]; bool instr_valid = icode in { INOP, IHALT, IRRMOVQ, IIRMOVQ, IIADDQ, IRMMOVQ, IMRMOVQ, IOPQ, IJXX, ICALL, IRET, IPUSHQ, IPOPQ }; # Does fetched instruction require a regid byte? bool need_regids = icode in { IRRMOVQ, IOPQ, IPUSHQ, IPOPQ, IIRMOVQ, IIADDQ, IRMMOVQ, IMRMOVQ }; # Does fetched instruction require a constant word? bool need_valC = icode in { IIRMOVQ, IIADDQ, IRMMOVQ, IMRMOVQ, IJXX, ICALL }; ################ Decode Stage ################################### ## What register should be used as the A source? word srcA = [ icode in { IRRMOVQ, IRMMOVQ, IOPQ, IPUSHQ } : rA; icode in { IPOPQ, IRET } : RRSP; 1 : RNONE; # Don't need register ]; ## What register should be used as the B source? word srcB = [ icode in { IOPQ, IRMMOVQ, IMRMOVQ, IIADDQ } : rB; icode in { IPUSHQ, IPOPQ, ICALL, IRET } : RRSP; 1 : RNONE; # Don't need register ]; ## What register should be used as the E destination? word dstE = [ icode in { IRRMOVQ } && Cnd : rB; icode in { IIRMOVQ, IOPQ, IIADDQ} : rB; icode in { IPUSHQ, IPOPQ, ICALL, IRET } : RRSP; 1 : RNONE; # Don't write any register ]; ## What register should be used as the M destination? word dstM = [ icode in { IMRMOVQ, IPOPQ } : rA; 1 : RNONE; # Don't write any register ]; ################ Execute Stage ################################### ## Select input A to ALU word aluA = [ icode in { IRRMOVQ, IOPQ } : valA; icode in { IIRMOVQ, IRMMOVQ, IMRMOVQ, IIADDQ } : valC; icode in { ICALL, IPUSHQ } : -8; icode in { IRET, IPOPQ } : 8; # Other instructions don't need ALU ]; ## Select input B to ALU word aluB = [ icode in { IRMMOVQ, IMRMOVQ, IOPQ, ICALL, IPUSHQ, IRET, IPOPQ, IIADDQ } : valB; icode in { IRRMOVQ, IIRMOVQ } : 0; # Other instructions don't need ALU ]; ## Set the ALU function word alufun = [ icode == IOPQ : ifun; 1 : ALUADD; ]; ## Should the condition codes be updated? bool set_cc = icode in { IOPQ, IIADDQ }; ################ Memory Stage ################################### ## Set read control signal bool mem_read = icode in { IMRMOVQ, IPOPQ, IRET }; ## Set write control signal bool mem_write = icode in { IRMMOVQ, IPUSHQ, ICALL }; ## Select memory address word mem_addr = [ icode in { IRMMOVQ, IPUSHQ, ICALL, IMRMOVQ } : valE; icode in { IPOPQ, IRET } : valA; # Other instructions don't need address ]; ## Select memory input data word mem_data = [ # Value from register icode in { IRMMOVQ, IPUSHQ } : valA; # Return PC icode == ICALL : valP; # Default: Don't write anything ]; ## Determine instruction status word Stat = [ imem_error || dmem_error : SADR; !instr_valid: SINS; icode == IHALT : SHLT; 1 : SAOK; ]; ################ Program Counter Update ############################ ## What address should instruction be fetched at word new_pc = [ # Call. Use instruction constant icode == ICALL : valC; # Taken branch. Use instruction constant icode == IJXX && Cnd : valC; # Completion of RET instruction. Use value from stack icode == IRET : valM; # Default: Use incremented PC 1 : valP; ]; #/* $end seq-all-hcl */模拟器测试结果截图(ISA Check Succeeds):
4.54
设计思想:
分析pipe-full.hcl,需要对Instr_valid, need_regids, need_valC, srcB, dstE, aluA, aluB, set_cc进行修改。
bool Instr_valid = ficode in{…}; 大括号中所列指令需加上IIADDQ
bool need_regids = ficode in{…}; 大括号中所列指令需加上IIADDQ
bool need_valC = ficode in{…}; 大括号中所列指令需加上IIADDQ
word d_srcB = [
D_icode in {…} : D_rB; 大括号中所列指令需加上IIADDQ
…
];
word d_dstE = [
D_icode in {…} : D_rB; 大括号中所列指令需加上IIADDQ
…
];
word aluA = [
…
E_icode in {… } : E_valC; 大括号中所列指令需加上IIADDQ
…
];
word aluB = [
icode in { … } : E_valB; 大括号中所列指令需加上IIADDQ
…
];
bool set_cc = E_icode == IOPQ && …改为:
boolset_cc = (E_icode == IOPQ || E_icode == IIADDQ) &&…修改后pipe-full.hcl文件:
#/* $begin pipe-all-hcl */ #################################################################### # HCL Description of Control for Pipelined Y86-64 Processor # # Copyright (C) Randal E. Bryant, David R. O'Hallaron, 2014 # #################################################################### ## Your task is to implement the iaddq instruction ## The file contains a declaration of the icodes ## for iaddq (IIADDQ) ## Your job is to add the rest of the logic to make it work #################################################################### # C Include's. Don't alter these # #################################################################### quote '#include <stdio.h>' quote '#include "isa.h"' quote '#include "pipeline.h"' quote '#include "stages.h"' quote '#include "sim.h"' quote 'int sim_main(int argc, char *argv[]);' quote 'int main(int argc, char *argv[]){return sim_main(argc,argv);}' #################################################################### # Declarations. Do not change/remove/delete any of these # #################################################################### ##### Symbolic representation of Y86-64 Instruction Codes ############# wordsig INOP 'I_NOP' wordsig IHALT 'I_HALT' wordsig IRRMOVQ 'I_RRMOVQ' wordsig IIRMOVQ 'I_IRMOVQ' wordsig IRMMOVQ 'I_RMMOVQ' wordsig IMRMOVQ 'I_MRMOVQ' wordsig IOPQ 'I_ALU' wordsig IJXX 'I_JMP' wordsig ICALL 'I_CALL' wordsig IRET 'I_RET' wordsig IPUSHQ 'I_PUSHQ' wordsig IPOPQ 'I_POPQ' # Instruction code for iaddq instruction wordsig IIADDQ 'I_IADDQ' ##### Symbolic represenations of Y86-64 function codes ##### wordsig FNONE 'F_NONE' # Default function code ##### Symbolic representation of Y86-64 Registers referenced ##### wordsig RRSP 'REG_RSP' # Stack Pointer wordsig RNONE 'REG_NONE' # Special value indicating "no register" ##### ALU Functions referenced explicitly ########################## wordsig ALUADD 'A_ADD' # ALU should add its arguments ##### Possible instruction status values ##### wordsig SBUB 'STAT_BUB' # Bubble in stage wordsig SAOK 'STAT_AOK' # Normal execution wordsig SADR 'STAT_ADR' # Invalid memory address wordsig SINS 'STAT_INS' # Invalid instruction wordsig SHLT 'STAT_HLT' # Halt instruction encountered ##### Signals that can be referenced by control logic ############## ##### Pipeline Register F ########################################## wordsig F_predPC 'pc_curr->pc' # Predicted value of PC ##### Intermediate Values in Fetch Stage ########################### wordsig imem_icode 'imem_icode' # icode field from instruction memory wordsig imem_ifun 'imem_ifun' # ifun field from instruction memory wordsig f_icode 'if_id_next->icode' # (Possibly modified) instruction code wordsig f_ifun 'if_id_next->ifun' # Fetched instruction function wordsig f_valC 'if_id_next->valc' # Constant data of fetched instruction wordsig f_valP 'if_id_next->valp' # Address of following instruction boolsig imem_error 'imem_error' # Error signal from instruction memory boolsig instr_valid 'instr_valid' # Is fetched instruction valid? ##### Pipeline Register D ########################################## wordsig D_icode 'if_id_curr->icode' # Instruction code wordsig D_rA 'if_id_curr->ra' # rA field from instruction wordsig D_rB 'if_id_curr->rb' # rB field from instruction wordsig D_valP 'if_id_curr->valp' # Incremented PC ##### Intermediate Values in Decode Stage ######################### wordsig d_srcA 'id_ex_next->srca' # srcA from decoded instruction wordsig d_srcB 'id_ex_next->srcb' # srcB from decoded instruction wordsig d_rvalA 'd_regvala' # valA read from register file wordsig d_rvalB 'd_regvalb' # valB read from register file ##### Pipeline Register E ########################################## wordsig E_icode 'id_ex_curr->icode' # Instruction code wordsig E_ifun 'id_ex_curr->ifun' # Instruction function wordsig E_valC 'id_ex_curr->valc' # Constant data wordsig E_srcA 'id_ex_curr->srca' # Source A register ID wordsig E_valA 'id_ex_curr->vala' # Source A value wordsig E_srcB 'id_ex_curr->srcb' # Source B register ID wordsig E_valB 'id_ex_curr->valb' # Source B value wordsig E_dstE 'id_ex_curr->deste' # Destination E register ID wordsig E_dstM 'id_ex_curr->destm' # Destination M register ID ##### Intermediate Values in Execute Stage ######################### wordsig e_valE 'ex_mem_next->vale' # valE generated by ALU boolsig e_Cnd 'ex_mem_next->takebranch' # Does condition hold? wordsig e_dstE 'ex_mem_next->deste' # dstE (possibly modified to be RNONE) ##### Pipeline Register M ######################### wordsig M_stat 'ex_mem_curr->status' # Instruction status wordsig M_icode 'ex_mem_curr->icode' # Instruction code wordsig M_ifun 'ex_mem_curr->ifun' # Instruction function wordsig M_valA 'ex_mem_curr->vala' # Source A value wordsig M_dstE 'ex_mem_curr->deste' # Destination E register ID wordsig M_valE 'ex_mem_curr->vale' # ALU E value wordsig M_dstM 'ex_mem_curr->destm' # Destination M register ID boolsig M_Cnd 'ex_mem_curr->takebranch' # Condition flag boolsig dmem_error 'dmem_error' # Error signal from instruction memory ##### Intermediate Values in Memory Stage ########################## wordsig m_valM 'mem_wb_next->valm' # valM generated by memory wordsig m_stat 'mem_wb_next->status' # stat (possibly modified to be SADR) ##### Pipeline Register W ########################################## wordsig W_stat 'mem_wb_curr->status' # Instruction status wordsig W_icode 'mem_wb_curr->icode' # Instruction code wordsig W_dstE 'mem_wb_curr->deste' # Destination E register ID wordsig W_valE 'mem_wb_curr->vale' # ALU E value wordsig W_dstM 'mem_wb_curr->destm' # Destination M register ID wordsig W_valM 'mem_wb_curr->valm' # Memory M value #################################################################### # Control Signal Definitions. # #################################################################### ################ Fetch Stage ################################### ## What address should instruction be fetched at word f_pc = [ # Mispredicted branch. Fetch at incremented PC M_icode == IJXX && !M_Cnd : M_valA; # Completion of RET instruction W_icode == IRET : W_valM; # Default: Use predicted value of PC 1 : F_predPC; ]; ## Determine icode of fetched instruction word f_icode = [ imem_error : INOP; 1: imem_icode; ]; # Determine ifun word f_ifun = [ imem_error : FNONE; 1: imem_ifun; ]; # Is instruction valid? bool instr_valid = f_icode in { INOP, IHALT, IRRMOVQ, IIRMOVQ, IRMMOVQ, IMRMOVQ, IOPQ, IJXX, ICALL, IRET, IPUSHQ, IPOPQ, IIADDQ }; # Determine status code for fetched instruction word f_stat = [ imem_error: SADR; !instr_valid : SINS; f_icode == IHALT : SHLT; 1 : SAOK; ]; # Does fetched instruction require a regid byte? bool need_regids = f_icode in { IRRMOVQ, IOPQ, IPUSHQ, IPOPQ, IIRMOVQ, IRMMOVQ, IMRMOVQ, IIADDQ }; # Does fetched instruction require a constant word? bool need_valC = f_icode in { IIRMOVQ, IRMMOVQ, IMRMOVQ, IJXX, ICALL, IIADDQ }; # Predict next value of PC word f_predPC = [ f_icode in { IJXX, ICALL } : f_valC; 1 : f_valP; ]; ################ Decode Stage ###################################### ## What register should be used as the A source? word d_srcA = [ D_icode in { IRRMOVQ, IRMMOVQ, IOPQ, IPUSHQ } : D_rA; D_icode in { IPOPQ, IRET } : RRSP; 1 : RNONE; # Don't need register ]; ## What register should be used as the B source? word d_srcB = [ D_icode in { IOPQ, IRMMOVQ, IMRMOVQ, IIADDQ } : D_rB; D_icode in { IPUSHQ, IPOPQ, ICALL, IRET } : RRSP; 1 : RNONE; # Don't need register ]; ## What register should be used as the E destination? word d_dstE = [ D_icode in { IRRMOVQ, IIRMOVQ, IOPQ, IIADDQ} : D_rB; D_icode in { IPUSHQ, IPOPQ, ICALL, IRET } : RRSP; 1 : RNONE; # Don't write any register ]; ## What register should be used as the M destination? word d_dstM = [ D_icode in { IMRMOVQ, IPOPQ } : D_rA; 1 : RNONE; # Don't write any register ]; ## What should be the A value? ## Forward into decode stage for valA word d_valA = [ D_icode in { ICALL, IJXX } : D_valP; # Use incremented PC d_srcA == e_dstE : e_valE; # Forward valE from execute d_srcA == M_dstM : m_valM; # Forward valM from memory d_srcA == M_dstE : M_valE; # Forward valE from memory d_srcA == W_dstM : W_valM; # Forward valM from write back d_srcA == W_dstE : W_valE; # Forward valE from write back 1 : d_rvalA; # Use value read from register file ]; word d_valB = [ d_srcB == e_dstE : e_valE; # Forward valE from execute d_srcB == M_dstM : m_valM; # Forward valM from memory d_srcB == M_dstE : M_valE; # Forward valE from memory d_srcB == W_dstM : W_valM; # Forward valM from write back d_srcB == W_dstE : W_valE; # Forward valE from write back 1 : d_rvalB; # Use value read from register file ]; ################ Execute Stage ##################################### ## Select input A to ALU word aluA = [ E_icode in { IRRMOVQ, IOPQ } : E_valA; E_icode in { IIRMOVQ, IRMMOVQ, IMRMOVQ, IIADDQ } : E_valC; E_icode in { ICALL, IPUSHQ } : -8; E_icode in { IRET, IPOPQ } : 8; # Other instructions don't need ALU ]; ## Select input B to ALU word aluB = [ E_icode in { IRMMOVQ, IMRMOVQ, IOPQ, ICALL, IPUSHQ, IRET, IPOPQ, IIADDQ } : E_valB; E_icode in { IRRMOVQ, IIRMOVQ } : 0; # Other instructions don't need ALU ]; ## Set the ALU function word alufun = [ E_icode == IOPQ : E_ifun; 1 : ALUADD; ]; ## Should the condition codes be updated? bool set_cc = (E_icode == IOPQ || E_icode == IIADDQ) && # State changes only during normal operation !m_stat in { SADR, SINS, SHLT } && !W_stat in { SADR, SINS, SHLT }; ## Generate valA in execute stage word e_valA = E_valA; # Pass valA through stage ## Set dstE to RNONE in event of not-taken conditional move word e_dstE = [ E_icode == IRRMOVQ && !e_Cnd : RNONE; 1 : E_dstE; ]; ################ Memory Stage ###################################### ## Select memory address word mem_addr = [ M_icode in { IRMMOVQ, IPUSHQ, ICALL, IMRMOVQ } : M_valE; M_icode in { IPOPQ, IRET } : M_valA; # Other instructions don't need address ]; ## Set read control signal bool mem_read = M_icode in { IMRMOVQ, IPOPQ, IRET }; ## Set write control signal bool mem_write = M_icode in { IRMMOVQ, IPUSHQ, ICALL }; #/* $begin pipe-m_stat-hcl */ ## Update the status word m_stat = [ dmem_error : SADR; 1 : M_stat; ]; #/* $end pipe-m_stat-hcl */ ## Set E port register ID word w_dstE = W_dstE; ## Set E port value word w_valE = W_valE; ## Set M port register ID word w_dstM = W_dstM; ## Set M port value word w_valM = W_valM; ## Update processor status word Stat = [ W_stat == SBUB : SAOK; 1 : W_stat; ]; ################ Pipeline Register Control ######################### # Should I stall or inject a bubble into Pipeline Register F? # At most one of these can be true. bool F_bubble = 0; bool F_stall = # Conditions for a load/use hazard E_icode in { IMRMOVQ, IPOPQ } && E_dstM in { d_srcA, d_srcB } || # Stalling at fetch while ret passes through pipeline IRET in { D_icode, E_icode, M_icode }; # Should I stall or inject a bubble into Pipeline Register D? # At most one of these can be true. bool D_stall = # Conditions for a load/use hazard E_icode in { IMRMOVQ, IPOPQ } && E_dstM in { d_srcA, d_srcB }; bool D_bubble = # Mispredicted branch (E_icode == IJXX && !e_Cnd) || # Stalling at fetch while ret passes through pipeline # but not condition for a load/use hazard !(E_icode in { IMRMOVQ, IPOPQ } && E_dstM in { d_srcA, d_srcB }) && IRET in { D_icode, E_icode, M_icode }; # Should I stall or inject a bubble into Pipeline Register E? # At most one of these can be true. bool E_stall = 0; bool E_bubble = # Mispredicted branch (E_icode == IJXX && !e_Cnd) || # Conditions for a load/use hazard E_icode in { IMRMOVQ, IPOPQ } && E_dstM in { d_srcA, d_srcB}; # Should I stall or inject a bubble into Pipeline Register M? # At most one of these can be true. bool M_stall = 0; # Start injecting bubbles as soon as exception passes through memory stage bool M_bubble = m_stat in { SADR, SINS, SHLT } || W_stat in { SADR, SINS, SHLT }; # Should I stall or inject a bubble into Pipeline Register W? bool W_stall = W_stat in { SADR, SINS, SHLT }; bool W_bubble = 0; #/* $end pipe-all-hcl */模拟器测试结果截图(ISA Checks Succeed):
4.56
设计思想:
分析pipe-btfnt.hcl,需要对f_pc, fpredPC, aluA, aluB, D_bubble, E_bubble进行修改。
word f_pc = [
M_icode == IJXX && !M_Cnd : M_valA;
W_icode == IRET : W_valM;
1 : F_predPC;
];
修改为:
word f_pc = [
M_icode == IJXX && M_ifun != UNCOND&& M_valE < M_valA && !M_Cnd : M_valA;
W_icode == IJXX && M_ifun != UNCOND&& M_valE >= M_valA && M_Cnd : M_valE;
W_icode == IRET : W_valM;
1 : F_predPC;
];
word f_predPC = [
f_icode in { IJXX, ICALL } : f_valC;
1 : f_valP;
];
修改为:
word f_predPC = [
f_icode == IJXX && f_ifun != UNCOND&& f_valC < f_valP : f_valC;
f_icode == IJXX && f_ifun != UNCOND&& f_valC >= f_valP : f_valP;
f_icode in { IJXX, ICALL } : f_valC;
1 : f_valP;
];
word aluA = [
…
E_icode in { IIRMOVQ, IRMMOVQ, IMRMOVQ } :E_valC;大括号列指令需加上IJXX
…
];
word aluB = [
…
E_icode in { IRRMOVQ, IIRMOVQ } :0;大括号列指令需加上IJXX
…
];
bool D_bubble =
(E_icode == IJXX && !e_Cnd) || !(E_icode in { IMRMOVQ, IPOPQ } && E_dstM in { d_srcA, d_srcB })&& IRET in { D_icode, E_icode, M_icode };
修改为:
bool D_bubble =
(E_icode == IJXX && E_ifun !=UNCOND && E_valC < E_valA && !e_Cnd) || (E_icode == IJXX && E_ifun !=UNCOND && E_valC >= E_valA && e_Cnd)||! (E_icode in { IMRMOVQ, IPOPQ } && E_dstM in { d_srcA, d_srcB })&& IRET in { D_icode, E_icode, M_icode };
bool E_bubble =
(E_icode == IJXX && !e_Cnd) ||E_icode in { IMRMOVQ, IPOPQ } && E_dstM in { d_srcA, d_srcB };
修改为:
bool E_bubble =
(E_icode== IJXX && E_ifun != UNCOND && E_valC < E_valA &&!e_Cnd) || (E_icode == IJXX && E_ifun != UNCOND && E_valC >=E_valA && e_Cnd)|| E_icode in { IMRMOVQ, IPOPQ} && E_dstM in { d_srcA, d_srcB };修改后pipe-btfnt.hcl文件:
#/* $begin pipe-all-hcl */ #################################################################### # HCL Description of Control for Pipelined Y86-64 Processor # # Copyright (C) Randal E. Bryant, David R. O'Hallaron, 2014 # #################################################################### ## Your task is to modify the design so that conditional branches are ## predicted as being taken when backward and not-taken when forward ## The code here is nearly identical to that for the normal pipeline. ## Comments starting with keyword "BBTFNT" have been added at places ## relevant to the exercise. #################################################################### # C Include's. Don't alter these # #################################################################### quote '#include <stdio.h>' quote '#include "isa.h"' quote '#include "pipeline.h"' quote '#include "stages.h"' quote '#include "sim.h"' quote 'int sim_main(int argc, char *argv[]);' quote 'int main(int argc, char *argv[]){return sim_main(argc,argv);}' #################################################################### # Declarations. Do not change/remove/delete any of these # #################################################################### ##### Symbolic representation of Y86-64 Instruction Codes ############# wordsig INOP 'I_NOP' wordsig IHALT 'I_HALT' wordsig IRRMOVQ 'I_RRMOVQ' wordsig IIRMOVQ 'I_IRMOVQ' wordsig IRMMOVQ 'I_RMMOVQ' wordsig IMRMOVQ 'I_MRMOVQ' wordsig IOPQ 'I_ALU' wordsig IJXX 'I_JMP' wordsig ICALL 'I_CALL' wordsig IRET 'I_RET' wordsig IPUSHQ 'I_PUSHQ' wordsig IPOPQ 'I_POPQ' ##### Symbolic represenations of Y86-64 function codes ##### wordsig FNONE 'F_NONE' # Default function code ##### Symbolic representation of Y86-64 Registers referenced ##### wordsig RRSP 'REG_RSP' # Stack Pointer wordsig RNONE 'REG_NONE' # Special value indicating "no register" ##### ALU Functions referenced explicitly ########################## wordsig ALUADD 'A_ADD' # ALU should add its arguments ## BBTFNT: For modified branch prediction, need to distinguish ## conditional vs. unconditional branches ##### Jump conditions referenced explicitly wordsig UNCOND 'C_YES' # Unconditional transfer ##### Possible instruction status values ##### wordsig SBUB 'STAT_BUB' # Bubble in stage wordsig SAOK 'STAT_AOK' # Normal execution wordsig SADR 'STAT_ADR' # Invalid memory address wordsig SINS 'STAT_INS' # Invalid instruction wordsig SHLT 'STAT_HLT' # Halt instruction encountered ##### Signals that can be referenced by control logic ############## ##### Pipeline Register F ########################################## wordsig F_predPC 'pc_curr->pc' # Predicted value of PC ##### Intermediate Values in Fetch Stage ########################### wordsig imem_icode 'imem_icode' # icode field from instruction memory wordsig imem_ifun 'imem_ifun' # ifun field from instruction memory wordsig f_icode 'if_id_next->icode' # (Possibly modified) instruction code wordsig f_ifun 'if_id_next->ifun' # Fetched instruction function wordsig f_valC 'if_id_next->valc' # Constant data of fetched instruction wordsig f_valP 'if_id_next->valp' # Address of following instruction boolsig imem_error 'imem_error' # Error signal from instruction memory boolsig instr_valid 'instr_valid' # Is fetched instruction valid? ##### Pipeline Register D ########################################## wordsig D_icode 'if_id_curr->icode' # Instruction code wordsig D_rA 'if_id_curr->ra' # rA field from instruction wordsig D_rB 'if_id_curr->rb' # rB field from instruction wordsig D_valP 'if_id_curr->valp' # Incremented PC ##### Intermediate Values in Decode Stage ######################### wordsig d_srcA 'id_ex_next->srca' # srcA from decoded instruction wordsig d_srcB 'id_ex_next->srcb' # srcB from decoded instruction wordsig d_rvalA 'd_regvala' # valA read from register file wordsig d_rvalB 'd_regvalb' # valB read from register file ##### Pipeline Register E ########################################## wordsig E_icode 'id_ex_curr->icode' # Instruction code wordsig E_ifun 'id_ex_curr->ifun' # Instruction function wordsig E_valC 'id_ex_curr->valc' # Constant data wordsig E_srcA 'id_ex_curr->srca' # Source A register ID wordsig E_valA 'id_ex_curr->vala' # Source A value wordsig E_srcB 'id_ex_curr->srcb' # Source B register ID wordsig E_valB 'id_ex_curr->valb' # Source B value wordsig E_dstE 'id_ex_curr->deste' # Destination E register ID wordsig E_dstM 'id_ex_curr->destm' # Destination M register ID ##### Intermediate Values in Execute Stage ######################### wordsig e_valE 'ex_mem_next->vale' # valE generated by ALU boolsig e_Cnd 'ex_mem_next->takebranch' # Does condition hold? wordsig e_dstE 'ex_mem_next->deste' # dstE (possibly modified to be RNONE) ##### Pipeline Register M ######################### wordsig M_stat 'ex_mem_curr->status' # Instruction status wordsig M_icode 'ex_mem_curr->icode' # Instruction code wordsig M_ifun 'ex_mem_curr->ifun' # Instruction function wordsig M_valA 'ex_mem_curr->vala' # Source A value wordsig M_dstE 'ex_mem_curr->deste' # Destination E register ID wordsig M_valE 'ex_mem_curr->vale' # ALU E value wordsig M_dstM 'ex_mem_curr->destm' # Destination M register ID boolsig M_Cnd 'ex_mem_curr->takebranch' # Condition flag boolsig dmem_error 'dmem_error' # Error signal from instruction memory ##### Intermediate Values in Memory Stage ########################## wordsig m_valM 'mem_wb_next->valm' # valM generated by memory wordsig m_stat 'mem_wb_next->status' # stat (possibly modified to be SADR) ##### Pipeline Register W ########################################## wordsig W_stat 'mem_wb_curr->status' # Instruction status wordsig W_icode 'mem_wb_curr->icode' # Instruction code wordsig W_dstE 'mem_wb_curr->deste' # Destination E register ID wordsig W_valE 'mem_wb_curr->vale' # ALU E value wordsig W_dstM 'mem_wb_curr->destm' # Destination M register ID wordsig W_valM 'mem_wb_curr->valm' # Memory M value #################################################################### # Control Signal Definitions. # #################################################################### ################ Fetch Stage ################################### ## What address should instruction be fetched at word f_pc = [ # Mispredicted branch. Fetch at incremented PC # backward M_icode == IJXX && M_ifun != UNCOND && M_valE < M_valA && !M_Cnd : M_valA; # forward M_icode == IJXX && M_ifun != UNCOND && M_valE >= M_valA && M_Cnd : M_valE; # Completion of RET instruction W_icode == IRET : W_valM; # Default: Use predicted value of PC 1 : F_predPC; ]; ## Determine icode of fetched instruction word f_icode = [ imem_error : INOP; 1: imem_icode; ]; # Determine ifun word f_ifun = [ imem_error : FNONE; 1: imem_ifun; ]; # Is instruction valid? bool instr_valid = f_icode in { INOP, IHALT, IRRMOVQ, IIRMOVQ, IRMMOVQ, IMRMOVQ, IOPQ, IJXX, ICALL, IRET, IPUSHQ, IPOPQ }; # Determine status code for fetched instruction word f_stat = [ imem_error: SADR; !instr_valid : SINS; f_icode == IHALT : SHLT; 1 : SAOK; ]; # Does fetched instruction require a regid byte? bool need_regids = f_icode in { IRRMOVQ, IOPQ, IPUSHQ, IPOPQ, IIRMOVQ, IRMMOVQ, IMRMOVQ }; # Does fetched instruction require a constant word? bool need_valC = f_icode in { IIRMOVQ, IRMMOVQ, IMRMOVQ, IJXX, ICALL }; # Predict next value of PC word f_predPC = [ # BBTFNT: This is where you'll change the branch prediction rule f_icode == IJXX && f_ifun != UNCOND && f_valC < f_valP : f_valC; f_icode == IJXX && f_ifun != UNCOND && f_valC >= f_valP : f_valP; f_icode in { IJXX, ICALL } : f_valC; 1 : f_valP; ]; ################ Decode Stage ###################################### ## What register should be used as the A source? word d_srcA = [ D_icode in { IRRMOVQ, IRMMOVQ, IOPQ, IPUSHQ } : D_rA; D_icode in { IPOPQ, IRET } : RRSP; 1 : RNONE; # Don't need register ]; ## What register should be used as the B source? word d_srcB = [ D_icode in { IOPQ, IRMMOVQ, IMRMOVQ } : D_rB; D_icode in { IPUSHQ, IPOPQ, ICALL, IRET } : RRSP; 1 : RNONE; # Don't need register ]; ## What register should be used as the E destination? word d_dstE = [ D_icode in { IRRMOVQ, IIRMOVQ, IOPQ} : D_rB; D_icode in { IPUSHQ, IPOPQ, ICALL, IRET } : RRSP; 1 : RNONE; # Don't write any register ]; ## What register should be used as the M destination? word d_dstM = [ D_icode in { IMRMOVQ, IPOPQ } : D_rA; 1 : RNONE; # Don't write any register ]; ## What should be the A value? ## Forward into decode stage for valA word d_valA = [ D_icode in { ICALL, IJXX } : D_valP; # Use incremented PC d_srcA == e_dstE : e_valE; # Forward valE from execute d_srcA == M_dstM : m_valM; # Forward valM from memory d_srcA == M_dstE : M_valE; # Forward valE from memory d_srcA == W_dstM : W_valM; # Forward valM from write back d_srcA == W_dstE : W_valE; # Forward valE from write back 1 : d_rvalA; # Use value read from register file ]; word d_valB = [ d_srcB == e_dstE : e_valE; # Forward valE from execute d_srcB == M_dstM : m_valM; # Forward valM from memory d_srcB == M_dstE : M_valE; # Forward valE from memory d_srcB == W_dstM : W_valM; # Forward valM from write back d_srcB == W_dstE : W_valE; # Forward valE from write back 1 : d_rvalB; # Use value read from register file ]; ################ Execute Stage ##################################### # BBTFNT: When some branches are predicted as not-taken, you need some # way to get valC into pipeline register M, so that # you can correct for a mispredicted branch. ## Select input A to ALU word aluA = [ E_icode in { IRRMOVQ, IOPQ } : E_valA; E_icode in { IIRMOVQ, IRMMOVQ, IMRMOVQ, IJXX } : E_valC; E_icode in { ICALL, IPUSHQ } : -8; E_icode in { IRET, IPOPQ } : 8; # Other instructions don't need ALU ]; ## Select input B to ALU word aluB = [ E_icode in { IRMMOVQ, IMRMOVQ, IOPQ, ICALL, IPUSHQ, IRET, IPOPQ } : E_valB; E_icode in { IRRMOVQ, IIRMOVQ, IJXX } : 0; # Other instructions don't need ALU ]; ## Set the ALU function word alufun = [ E_icode == IOPQ : E_ifun; 1 : ALUADD; ]; ## Should the condition codes be updated? bool set_cc = E_icode == IOPQ && # State changes only during normal operation !m_stat in { SADR, SINS, SHLT } && !W_stat in { SADR, SINS, SHLT }; ## Generate valA in execute stage word e_valA = E_valA; # Pass valA through stage ## Set dstE to RNONE in event of not-taken conditional move word e_dstE = [ E_icode == IRRMOVQ && !e_Cnd : RNONE; 1 : E_dstE; ]; ################ Memory Stage ###################################### ## Select memory address word mem_addr = [ M_icode in { IRMMOVQ, IPUSHQ, ICALL, IMRMOVQ } : M_valE; M_icode in { IPOPQ, IRET } : M_valA; # Other instructions don't need address ]; ## Set read control signal bool mem_read = M_icode in { IMRMOVQ, IPOPQ, IRET }; ## Set write control signal bool mem_write = M_icode in { IRMMOVQ, IPUSHQ, ICALL }; #/* $begin pipe-m_stat-hcl */ ## Update the status word m_stat = [ dmem_error : SADR; 1 : M_stat; ]; #/* $end pipe-m_stat-hcl */ ## Set E port register ID word w_dstE = W_dstE; ## Set E port value word w_valE = W_valE; ## Set M port register ID word w_dstM = W_dstM; ## Set M port value word w_valM = W_valM; ## Update processor status word Stat = [ W_stat == SBUB : SAOK; 1 : W_stat; ]; ################ Pipeline Register Control ######################### # Should I stall or inject a bubble into Pipeline Register F? # At most one of these can be true. bool F_bubble = 0; bool F_stall = # Conditions for a load/use hazard E_icode in { IMRMOVQ, IPOPQ } && E_dstM in { d_srcA, d_srcB } || # Stalling at fetch while ret passes through pipeline IRET in { D_icode, E_icode, M_icode }; # Should I stall or inject a bubble into Pipeline Register D? # At most one of these can be true. bool D_stall = # Conditions for a load/use hazard E_icode in { IMRMOVQ, IPOPQ } && E_dstM in { d_srcA, d_srcB }; bool D_bubble = # Mispredicted branch: backward taken error or forward not-taken error ( (E_icode == IJXX && E_ifun != UNCOND && E_valC < E_valA && !e_Cnd) || (E_icode == IJXX && E_ifun != UNCOND && E_valC >= E_valA && e_Cnd) ) || # BBTFNT: This condition will change # Stalling at fetch while ret passes through pipeline # but not condition for a load/use hazard !(E_icode in { IMRMOVQ, IPOPQ } && E_dstM in { d_srcA, d_srcB }) && IRET in { D_icode, E_icode, M_icode }; # Should I stall or inject a bubble into Pipeline Register E? # At most one of these can be true. bool E_stall = 0; bool E_bubble = # Mispredicted branch: backward taken error or forward not-taken error ( (E_icode == IJXX && E_ifun != UNCOND && E_valC < E_valA && !e_Cnd) || (E_icode == IJXX && E_ifun != UNCOND && E_valC >= E_valA && e_Cnd) ) || # BBTFNT: This condition will change # Conditions for a load/use hazard E_icode in { IMRMOVQ, IPOPQ } && E_dstM in { d_srcA, d_srcB}; # Should I stall or inject a bubble into Pipeline Register M? # At most one of these can be true. bool M_stall = 0; # Start injecting bubbles as soon as exception passes through memory stage bool M_bubble = m_stat in { SADR, SINS, SHLT } || W_stat in { SADR, SINS, SHLT }; # Should I stall or inject a bubble into Pipeline Register W? bool W_stall = W_stat in { SADR, SINS, SHLT }; bool W_bubble = 0; #/* $end pipe-all-hcl */模拟器测试结果截图(ISA Checks Succeed):
4.58
设计思想:
分析pipe-1w.hcl,需要对f_icode, instr_valid,need_regids, f_predPC, d_srcA, d_srcB, d_dstM, aluA, aluB, mem_addr, mem_read,F_stall, D_stall, D_bubble, E_bubble进行修改。
word f_icode = [
Imem_error : INOP;
1 : imem_icode;
];
修改为:
word f_icode = [
Imem_error : INOP;
D_icode == IPOPQ : IPOP2;
1 : imem_icode;
];
bool instr_valid = f_icode in{…}; 大括号中所列指令需加上IPOP2
bool need_regids = f_icode in{…}; 大括号中所列指令需加上IPOP2
word f_predPC = [
f_icode in { IJXX, ICALL } : f_valC;
1 : f_valP;
];
修改为:
word f_predPC = [
f_icode in { IJXX, ICALL } : f_valC;
f_icode == IPOPQ : f_pc;
1 : f_valP;
];
word d_srcA = [
..
D_icode in { RET } : RRSP; 大括号中所列指令需加上IPOP2
…
];
word d_srcB = [
…
D_icode in { IPUSHQ, IPOPQ, ICALL, IRET } :RRSP;大括号中所列指令需加上IPOP2
…
];
word d_dstM = [
D_icode in { IMRMOVQ, IPOPQ } : D_rA;
1 : RNONE;
];
修改为:
word d_dstM = [
D_icode in { IMRMOVQ, IPOP2 } : D_rA;
1 : RNONE;
];
word aluA = [
…
E_icode in { ICALL, IPUSHQ } : -8 大括号中所列指令需加上IPOP2
…
];
word aluB = [
…
E_icode in { … } : E_valB; 大括号中所列指令需加上IPOP2
…
];
word mem_addr = [
M_icode in { IRMMOVQ, IPUSHQ, ICALL,IMRMOVQ } : M_valE;
M_icode in { IPOPQ, IRET } : M_valA;
];
修改为:
word mem_addr = [
M_icode in { IRMMOVQ, IPUSHQ, ICALL,IMRMOVQ, IPOP2} : M_valE;
M_icode in { IRET } : M_valA;
];
bool mem_read = M_icode in { IMRMOVQ,IPOPQ, IRET };
修改为:bool mem_read = M_icode in {IMRMOVQ, IPOP2, IRET };
bool F_stall =
E_icode in { IMRMOVQ, IPOPQ } &&E_dstM in { d_srcA, d_srcB } || IRET in { D_icode, E_icode, M_icode };
修改为:
bool F_stall =
E_icode in { IMRMOVQ, IPOP2 } &&E_dstM in { d_srcA, d_srcB } || IRET in { D_icode, E_icode, M_icode };
bool D_stall =
E_icode in { IMRMOVQ, IPOPQ } &&E_dstM in { d_srcA, d_srcB };
修改为:
bool D_stall =
E_icode in { IMRMOVQ, IPOP2 } &&E_dstM in { d_srcA, d_srcB };
bool D_bubble = …中IPOPQ换为IPOP2。
boolE_bubble = …中IPOPQ换为POP2。修改后pipe-1w.hcl文件:
#/* $begin pipe-all-hcl */ #################################################################### # HCL Description of Control for Pipelined Y86-64 Processor # # Copyright (C) Randal E. Bryant, David R. O'Hallaron, 2014 # #################################################################### ## Your task is to modify the design so that on any cycle, only ## one of the two possible (valE and valM) register writes will occur. ## This requires special handling of the popq instruction. ## Overall strategy: IPOPQ passes through pipe, ## treated as stack pointer increment, but not incrementing the PC ## On refetch, modify fetched icode to indicate an instruction "IPOP2", ## which reads from memory. ## This requires modifying the definition of f_icode ## and lots of other changes. Relevant positions to change ## are indicated by comments starting with keyword "1W". #################################################################### # C Include's. Don't alter these # #################################################################### quote '#include <stdio.h>' quote '#include "isa.h"' quote '#include "pipeline.h"' quote '#include "stages.h"' quote '#include "sim.h"' quote 'int sim_main(int argc, char *argv[]);' quote 'int main(int argc, char *argv[]){return sim_main(argc,argv);}' #################################################################### # Declarations. Do not change/remove/delete any of these # #################################################################### ##### Symbolic representation of Y86-64 Instruction Codes ############# wordsig INOP 'I_NOP' wordsig IHALT 'I_HALT' wordsig IRRMOVQ 'I_RRMOVQ' wordsig IIRMOVQ 'I_IRMOVQ' wordsig IRMMOVQ 'I_RMMOVQ' wordsig IMRMOVQ 'I_MRMOVQ' wordsig IOPQ 'I_ALU' wordsig IJXX 'I_JMP' wordsig ICALL 'I_CALL' wordsig IRET 'I_RET' wordsig IPUSHQ 'I_PUSHQ' wordsig IPOPQ 'I_POPQ' # 1W: Special instruction code for second try of popq wordsig IPOP2 'I_POP2' ##### Symbolic represenations of Y86-64 function codes ##### wordsig FNONE 'F_NONE' # Default function code ##### Symbolic representation of Y86-64 Registers referenced ##### wordsig RRSP 'REG_RSP' # Stack Pointer wordsig RNONE 'REG_NONE' # Special value indicating "no register" ##### ALU Functions referenced explicitly ########################## wordsig ALUADD 'A_ADD' # ALU should add its arguments ##### Possible instruction status values ##### wordsig SBUB 'STAT_BUB' # Bubble in stage wordsig SAOK 'STAT_AOK' # Normal execution wordsig SADR 'STAT_ADR' # Invalid memory address wordsig SINS 'STAT_INS' # Invalid instruction wordsig SHLT 'STAT_HLT' # Halt instruction encountered ##### Signals that can be referenced by control logic ############## ##### Pipeline Register F ########################################## wordsig F_predPC 'pc_curr->pc' # Predicted value of PC ##### Intermediate Values in Fetch Stage ########################### wordsig imem_icode 'imem_icode' # icode field from instruction memory wordsig imem_ifun 'imem_ifun' # ifun field from instruction memory wordsig f_icode 'if_id_next->icode' # (Possibly modified) instruction code wordsig f_ifun 'if_id_next->ifun' # Fetched instruction function wordsig f_valC 'if_id_next->valc' # Constant data of fetched instruction wordsig f_valP 'if_id_next->valp' # Address of following instruction ## 1W: Provide access to the PC value for the current instruction wordsig f_pc 'f_pc' # Address of fetched instruction boolsig imem_error 'imem_error' # Error signal from instruction memory boolsig instr_valid 'instr_valid' # Is fetched instruction valid? ##### Pipeline Register D ########################################## wordsig D_icode 'if_id_curr->icode' # Instruction code wordsig D_rA 'if_id_curr->ra' # rA field from instruction wordsig D_rB 'if_id_curr->rb' # rB field from instruction wordsig D_valP 'if_id_curr->valp' # Incremented PC ##### Intermediate Values in Decode Stage ######################### wordsig d_srcA 'id_ex_next->srca' # srcA from decoded instruction wordsig d_srcB 'id_ex_next->srcb' # srcB from decoded instruction wordsig d_rvalA 'd_regvala' # valA read from register file wordsig d_rvalB 'd_regvalb' # valB read from register file ##### Pipeline Register E ########################################## wordsig E_icode 'id_ex_curr->icode' # Instruction code wordsig E_ifun 'id_ex_curr->ifun' # Instruction function wordsig E_valC 'id_ex_curr->valc' # Constant data wordsig E_srcA 'id_ex_curr->srca' # Source A register ID wordsig E_valA 'id_ex_curr->vala' # Source A value wordsig E_srcB 'id_ex_curr->srcb' # Source B register ID wordsig E_valB 'id_ex_curr->valb' # Source B value wordsig E_dstE 'id_ex_curr->deste' # Destination E register ID wordsig E_dstM 'id_ex_curr->destm' # Destination M register ID ##### Intermediate Values in Execute Stage ######################### wordsig e_valE 'ex_mem_next->vale' # valE generated by ALU boolsig e_Cnd 'ex_mem_next->takebranch' # Does condition hold? wordsig e_dstE 'ex_mem_next->deste' # dstE (possibly modified to be RNONE) ##### Pipeline Register M ######################### wordsig M_stat 'ex_mem_curr->status' # Instruction status wordsig M_icode 'ex_mem_curr->icode' # Instruction code wordsig M_ifun 'ex_mem_curr->ifun' # Instruction function wordsig M_valA 'ex_mem_curr->vala' # Source A value wordsig M_dstE 'ex_mem_curr->deste' # Destination E register ID wordsig M_valE 'ex_mem_curr->vale' # ALU E value wordsig M_dstM 'ex_mem_curr->destm' # Destination M register ID boolsig M_Cnd 'ex_mem_curr->takebranch' # Condition flag boolsig dmem_error 'dmem_error' # Error signal from instruction memory ##### Intermediate Values in Memory Stage ########################## wordsig m_valM 'mem_wb_next->valm' # valM generated by memory wordsig m_stat 'mem_wb_next->status' # stat (possibly modified to be SADR) ##### Pipeline Register W ########################################## wordsig W_stat 'mem_wb_curr->status' # Instruction status wordsig W_icode 'mem_wb_curr->icode' # Instruction code wordsig W_dstE 'mem_wb_curr->deste' # Destination E register ID wordsig W_valE 'mem_wb_curr->vale' # ALU E value wordsig W_dstM 'mem_wb_curr->destm' # Destination M register ID wordsig W_valM 'mem_wb_curr->valm' # Memory M value #################################################################### # Control Signal Definitions. # #################################################################### ################ Fetch Stage ################################### ## What address should instruction be fetched at word f_pc = [ # Mispredicted branch. Fetch at incremented PC M_icode == IJXX && !M_Cnd : M_valA; # Completion of RET instruction W_icode == IRET : W_valM; # Default: Use predicted value of PC 1 : F_predPC; ]; ## Determine icode of fetched instruction ## 1W: To split ipopq into two cycles, need to be able to ## modify value of icode, ## so that it will be IPOP2 when fetched for second time. word f_icode = [ imem_error : INOP; D_icode == IPOPQ : IPOP2; 1: imem_icode; ]; # Determine ifun word f_ifun = [ imem_error : FNONE; 1: imem_ifun; ]; # Is instruction valid? bool instr_valid = f_icode in { INOP, IHALT, IRRMOVQ, IIRMOVQ, IRMMOVQ, IMRMOVQ, IOPQ, IJXX, ICALL, IRET, IPUSHQ, IPOPQ, IPOP2 }; # Determine status code for fetched instruction word f_stat = [ imem_error: SADR; !instr_valid : SINS; f_icode == IHALT : SHLT; 1 : SAOK; ]; # Does fetched instruction require a regid byte? bool need_regids = f_icode in { IRRMOVQ, IOPQ, IPUSHQ, IPOPQ, IIRMOVQ, IRMMOVQ, IMRMOVQ, IPOP2 }; # Does fetched instruction require a constant word? bool need_valC = f_icode in { IIRMOVQ, IRMMOVQ, IMRMOVQ, IJXX, ICALL }; # Predict next value of PC word f_predPC = [ f_icode in { IJXX, ICALL } : f_valC; ## 1W: Want to refetch popq one time f_icode == IPOPQ : f_pc; 1 : f_valP; ]; ################ Decode Stage ###################################### ## W1: Strategy. Decoding of popq rA should be treated the same ## as would iaddq $8, %rsp ## Decoding of pop2 rA treated same as mrmovq -8(%rsp), rA ## What register should be used as the A source? word d_srcA = [ D_icode in { IRRMOVQ, IRMMOVQ, IOPQ, IPUSHQ } : D_rA; D_icode in { IRET } : RRSP; 1 : RNONE; # Don't need register ]; ## What register should be used as the B source? word d_srcB = [ D_icode in { IOPQ, IRMMOVQ, IMRMOVQ } : D_rB; D_icode in { IPUSHQ, IPOPQ, ICALL, IRET, IPOP2 } : RRSP; 1 : RNONE; # Don't need register ]; ## What register should be used as the E destination? word d_dstE = [ D_icode in { IRRMOVQ, IIRMOVQ, IOPQ} : D_rB; D_icode in { IPUSHQ, IPOPQ, ICALL, IRET } : RRSP; 1 : RNONE; # Don't write any register ]; ## What register should be used as the M destination? word d_dstM = [ D_icode in { IMRMOVQ, IPOP2 } : D_rA; 1 : RNONE; # Don't write any register ]; ## What should be the A value? ## Forward into decode stage for valA word d_valA = [ D_icode in { ICALL, IJXX } : D_valP; # Use incremented PC d_srcA == e_dstE : e_valE; # Forward valE from execute d_srcA == M_dstM : m_valM; # Forward valM from memory d_srcA == M_dstE : M_valE; # Forward valE from memory d_srcA == W_dstM : W_valM; # Forward valM from write back d_srcA == W_dstE : W_valE; # Forward valE from write back 1 : d_rvalA; # Use value read from register file ]; word d_valB = [ d_srcB == e_dstE : e_valE; # Forward valE from execute d_srcB == M_dstM : m_valM; # Forward valM from memory d_srcB == M_dstE : M_valE; # Forward valE from memory d_srcB == W_dstM : W_valM; # Forward valM from write back d_srcB == W_dstE : W_valE; # Forward valE from write back 1 : d_rvalB; # Use value read from register file ]; ################ Execute Stage ##################################### ## Select input A to ALU word aluA = [ E_icode in { IRRMOVQ, IOPQ } : E_valA; E_icode in { IIRMOVQ, IRMMOVQ, IMRMOVQ } : E_valC; E_icode in { ICALL, IPUSHQ, IPOP2 } : -8; E_icode in { IRET, IPOPQ } : 8; # Other instructions don't need ALU ]; ## Select input B to ALU word aluB = [ E_icode in { IRMMOVQ, IMRMOVQ, IOPQ, ICALL, IPUSHQ, IRET, IPOPQ, IPOP2 } : E_valB; E_icode in { IRRMOVQ, IIRMOVQ } : 0; # Other instructions don't need ALU ]; ## Set the ALU function word alufun = [ E_icode == IOPQ : E_ifun; 1 : ALUADD; ]; ## Should the condition codes be updated? bool set_cc = E_icode == IOPQ && # State changes only during normal operation !m_stat in { SADR, SINS, SHLT } && !W_stat in { SADR, SINS, SHLT }; ## Generate valA in execute stage word e_valA = E_valA; # Pass valA through stage ## Set dstE to RNONE in event of not-taken conditional move word e_dstE = [ E_icode == IRRMOVQ && !e_Cnd : RNONE; 1 : E_dstE; ]; ################ Memory Stage ###################################### ## Select memory address word mem_addr = [ M_icode in { IRMMOVQ, IPUSHQ, ICALL, IMRMOVQ, IPOP2 } : M_valE; M_icode in { IRET } : M_valA; # Other instructions don't need address ]; ## Set read control signal bool mem_read = M_icode in { IMRMOVQ, IPOP2, IRET }; ## Set write control signal bool mem_write = M_icode in { IRMMOVQ, IPUSHQ, ICALL }; #/* $begin pipe-m_stat-hcl */ ## Update the status word m_stat = [ dmem_error : SADR; 1 : M_stat; ]; #/* $end pipe-m_stat-hcl */ ################ Write back stage ################################## ## 1W: For this problem, we introduce a multiplexor that merges ## valE and valM into a single value for writing to register port E. ## DO NOT CHANGE THIS LOGIC ## Merge both write back sources onto register port E ## Set E port register ID word w_dstE = [ ## writing from valM W_dstM != RNONE : W_dstM; 1: W_dstE; ]; ## Set E port value word w_valE = [ W_dstM != RNONE : W_valM; 1: W_valE; ]; ## Disable register port M ## Set M port register ID word w_dstM = RNONE; ## Set M port value word w_valM = 0; ## Update processor status word Stat = [ W_stat == SBUB : SAOK; 1 : W_stat; ]; ################ Pipeline Register Control ######################### # Should I stall or inject a bubble into Pipeline Register F? # At most one of these can be true. bool F_bubble = 0; bool F_stall = # Conditions for a load/use hazard E_icode in { IMRMOVQ, IPOP2 } && E_dstM in { d_srcA, d_srcB } || # Stalling at fetch while ret passes through pipeline IRET in { D_icode, E_icode, M_icode }; # Should I stall or inject a bubble into Pipeline Register D? # At most one of these can be true. bool D_stall = # Conditions for a load/use hazard E_icode in { IMRMOVQ, IPOP2 } && E_dstM in { d_srcA, d_srcB }; bool D_bubble = # Mispredicted branch (E_icode == IJXX && !e_Cnd) || # Stalling at fetch while ret passes through pipeline # but not condition for a load/use hazard !(E_icode in { IMRMOVQ, IPOP2 } && E_dstM in { d_srcA, d_srcB }) && # 1W: This condition will change IRET in { D_icode, E_icode, M_icode }; # Should I stall or inject a bubble into Pipeline Register E? # At most one of these can be true. bool E_stall = 0; bool E_bubble = # Mispredicted branch (E_icode == IJXX && !e_Cnd) || # Conditions for a load/use hazard E_icode in { IMRMOVQ, IPOP2 } && E_dstM in { d_srcA, d_srcB}; # Should I stall or inject a bubble into Pipeline Register M? # At most one of these can be true. bool M_stall = 0; # Start injecting bubbles as soon as exception passes through memory stage bool M_bubble = m_stat in { SADR, SINS, SHLT } || W_stat in { SADR, SINS, SHLT }; # Should I stall or inject a bubble into Pipeline Register W? bool W_stall = W_stat in { SADR, SINS, SHLT }; bool W_bubble = 0; #/* $end pipe-all-hcl */模拟器测试结果截图(ISA Checks Succeed):