void do_ex_stage()
{
alu_t alufun = gen_alufun();
bool_t setcc = gen_set_cc();
word_t alua, alub;
alua = gen_aluA();
alub = gen_aluB();
e_bcond = cond_holds(cc, id_ex_curr->ifun);
ex_mem_next->takebranch = e_bcond;
if (id_ex_curr->icode == I_JMP)
sim_log("\tExecute: instr = %s, cc = %s, branch %staken\n",
iname(HPACK(id_ex_curr->icode, id_ex_curr->ifun)),
cc_name(cc),
ex_mem_next->takebranch ? "" : "not ");
/* Perform the ALU operation */
word_t aluout = compute_alu(alufun, alua, alub);
ex_mem_next->vale = aluout;
sim_log("\tExecute: ALU: %c 0x%x 0x%x --> 0x%x\n",
op_name(alufun), alua, alub, aluout);
if (setcc) {
cc_in = compute_cc(alufun, alua, alub);
sim_log("\tExecute: New cc = %s\n", cc_name(cc_in));
}
ex_mem_next->icode = id_ex_curr->icode;
ex_mem_next->ifun = id_ex_curr->ifun;
ex_mem_next->vala = gen_e_valA();
ex_mem_next->deste = gen_e_dstE();
ex_mem_next->destm = id_ex_curr->destm;
ex_mem_next->srca = id_ex_curr->srca;
ex_mem_next->status = id_ex_curr->status;
ex_mem_next->stage_pc = id_ex_curr->stage_pc;
}
/* Execute single instruction. Return status. */
stat_t step_state(state_ptr s, FILE *error_file)
{
word_t argA, argB;
byte_t byte0 = 0;
byte_t byte1 = 0;
itype_t hi0;
alu_t lo0;
reg_id_t hi1 = REG_NONE;
reg_id_t lo1 = REG_NONE;
bool_t ok1 = TRUE;
word_t cval = 0;
word_t okc = TRUE;
word_t val, dval;
bool_t need_regids;
bool_t need_imm;
word_t ftpc = s->pc; /* Fall-through PC */
if (!get_byte_val(s->m, ftpc, &byte0)) {
if (error_file)
fprintf(error_file,
"PC = 0x%x, Invalid instruction address\n", s->pc);
return STAT_ADR;
}
ftpc++;
hi0 = HI4(byte0);
lo0 = LO4(byte0);
need_regids =
(hi0 == I_RRMOVL || hi0 == I_ALU || hi0 == I_PUSHL ||
hi0 == I_POPL || hi0 == I_IRMOVL || hi0 == I_RMMOVL ||
hi0 == I_MRMOVL || hi0 == I_IADDL || hi0 == I_ISUBL);
if (need_regids) {
ok1 = get_byte_val(s->m, ftpc, &byte1);
ftpc++;
hi1 = HI4(byte1);
lo1 = LO4(byte1);
}
need_imm =
(hi0 == I_IRMOVL || hi0 == I_RMMOVL || hi0 == I_MRMOVL ||
hi0 == I_JMP || hi0 == I_CALL || hi0 == I_IADDL || hi0 == I_ISUBL);
if (need_imm) {
okc = get_word_val(s->m, ftpc, &cval);
ftpc += 4;
}
switch (hi0) {
case I_NOP:
s->pc = ftpc;
break;
case I_HALT:
return STAT_HLT;
break;
case I_RRMOVL: /* Both unconditional and conditional moves */
if (!ok1) {
if (error_file)
fprintf(error_file,
"PC = 0x%x, Invalid instruction address\n", s->pc);
return STAT_ADR;
}
if (!reg_valid(hi1)) {
if (error_file)
fprintf(error_file,
"PC = 0x%x, Invalid register ID 0x%.1x\n",
s->pc, hi1);
return STAT_INS;
}
if (!reg_valid(lo1)) {
if (error_file)
fprintf(error_file,
"PC = 0x%x, Invalid register ID 0x%.1x\n",
s->pc, lo1);
return STAT_INS;
}
val = get_reg_val(s->r, hi1);
if (cond_holds(s->cc, lo0))
set_reg_val(s->r, lo1, val);
s->pc = ftpc;
break;
case I_IRMOVL:
if (!ok1) {
if (error_file)
fprintf(error_file,
"PC = 0x%x, Invalid instruction address\n", s->pc);
return STAT_ADR;
}
if (!okc) {
if (error_file)
fprintf(error_file,
"PC = 0x%x, Invalid instruction address",
s->pc);
return STAT_INS;
}
if (!reg_valid(lo1)) {
if (error_file)
fprintf(error_file,
"PC = 0x%x, Invalid register ID 0x%.1x\n",
s->pc, lo1);
return STAT_INS;
}
set_reg_val(s->r, lo1, cval);
s->pc = ftpc;
break;
case I_RMMOVL:
if (!ok1) {
if (error_file)
fprintf(error_file,
"PC = 0x%x, Invalid instruction address\n", s->pc);
return STAT_ADR;
}
if (!okc) {
if (error_file)
fprintf(error_file,
"PC = 0x%x, Invalid instruction address\n", s->pc);
return STAT_INS;
}
if (!reg_valid(hi1)) {
if (error_file)
fprintf(error_file,
"PC = 0x%x, Invalid register ID 0x%.1x\n",
s->pc, hi1);
return STAT_INS;
}
if (reg_valid(lo1))
cval += get_reg_val(s->r, lo1);
val = get_reg_val(s->r, hi1);
if (!set_word_val(s->m, cval, val)) {
if (error_file)
fprintf(error_file,
"PC = 0x%x, Invalid data address 0x%x\n",
s->pc, cval);
return STAT_ADR;
}
s->pc = ftpc;
break;
case I_MRMOVL:
if (!ok1) {
if (error_file)
fprintf(error_file,
"PC = 0x%x, Invalid instruction address\n", s->pc);
return STAT_ADR;
}
if (!okc) {
if (error_file)
fprintf(error_file,
"PC = 0x%x, Invalid instruction addres\n", s->pc);
return STAT_INS;
}
if (!reg_valid(hi1)) {
if (error_file)
fprintf(error_file,
"PC = 0x%x, Invalid register ID 0x%.1x\n",
s->pc, hi1);
return STAT_INS;
}
if (reg_valid(lo1))
cval += get_reg_val(s->r, lo1);
if (!get_word_val(s->m, cval, &val))
return STAT_ADR;
set_reg_val(s->r, hi1, val);
s->pc = ftpc;
break;
case I_ALU:
if (!ok1) {
if (error_file)
fprintf(error_file,
"PC = 0x%x, Invalid instruction address\n", s->pc);
return STAT_ADR;
}
argA = get_reg_val(s->r, hi1);
argB = get_reg_val(s->r, lo1);
val = compute_alu(lo0, argA, argB);
set_reg_val(s->r, lo1, val);
s->cc = compute_cc(lo0, argA, argB);
s->pc = ftpc;
break;
case I_JMP:
if (!ok1) {
if (error_file)
fprintf(error_file,
"PC = 0x%x, Invalid instruction address\n", s->pc);
return STAT_ADR;
}
if (!okc) {
if (error_file)
fprintf(error_file,
"PC = 0x%x, Invalid instruction address\n", s->pc);
return STAT_ADR;
}
if (cond_holds(s->cc, lo0))
s->pc = cval;
else
s->pc = ftpc;
break;
case I_CALL:
if (!ok1) {
if (error_file)
fprintf(error_file,
"PC = 0x%x, Invalid instruction address\n", s->pc);
return STAT_ADR;
}
if (!okc) {
if (error_file)
fprintf(error_file,
"PC = 0x%x, Invalid instruction address\n", s->pc);
return STAT_ADR;
}
val = get_reg_val(s->r, REG_ESP) - 4;
set_reg_val(s->r, REG_ESP, val);
if (!set_word_val(s->m, val, ftpc)) {
if (error_file)
fprintf(error_file,
"PC = 0x%x, Invalid stack address 0x%x\n", s->pc, val);
return STAT_ADR;
}
s->pc = cval;
break;
case I_RET:
/* Return Instruction. Pop address from stack */
dval = get_reg_val(s->r, REG_ESP);
if (!get_word_val(s->m, dval, &val)) {
if (error_file)
fprintf(error_file,
"PC = 0x%x, Invalid stack address 0x%x\n",
s->pc, dval);
return STAT_ADR;
}
set_reg_val(s->r, REG_ESP, dval + 4);
s->pc = val;
break;
case I_PUSHL:
if (!ok1) {
if (error_file)
fprintf(error_file,
"PC = 0x%x, Invalid instruction address\n", s->pc);
return STAT_ADR;
}
if (!reg_valid(hi1)) {
if (error_file)
fprintf(error_file,
"PC = 0x%x, Invalid register ID 0x%.1x\n", s->pc, hi1);
return STAT_INS;
}
val = get_reg_val(s->r, hi1);
dval = get_reg_val(s->r, REG_ESP) - 4;
set_reg_val(s->r, REG_ESP, dval);
if (!set_word_val(s->m, dval, val)) {
if (error_file)
fprintf(error_file,
"PC = 0x%x, Invalid stack address 0x%x\n", s->pc, dval);
return STAT_ADR;
}
s->pc = ftpc;
break;
case I_POPL:
if (!ok1) {
if (error_file)
fprintf(error_file,
"PC = 0x%x, Invalid instruction address\n", s->pc);
return STAT_ADR;
}
if (!reg_valid(hi1)) {
if (error_file)
fprintf(error_file,
"PC = 0x%x, Invalid register ID 0x%.1x\n", s->pc, hi1);
return STAT_INS;
}
dval = get_reg_val(s->r, REG_ESP);
set_reg_val(s->r, REG_ESP, dval+4);
if (!get_word_val(s->m, dval, &val)) {
if (error_file)
fprintf(error_file,
"PC = 0x%x, Invalid stack address 0x%x\n",
s->pc, dval);
return STAT_ADR;
}
set_reg_val(s->r, hi1, val);
s->pc = ftpc;
break;
case I_LEAVE:
dval = get_reg_val(s->r, REG_EBP);
set_reg_val(s->r, REG_ESP, dval+4);
if (!get_word_val(s->m, dval, &val)) {
if (error_file)
fprintf(error_file,
"PC = 0x%x, Invalid stack address 0x%x\n",
s->pc, dval);
return STAT_ADR;
}
set_reg_val(s->r, REG_EBP, val);
s->pc = ftpc;
break;
case I_IADDL:
if (!ok1) {
if (error_file)
fprintf(error_file,
"PC = 0x%x, Invalid instruction address\n", s->pc);
return STAT_ADR;
}
if (!okc) {
if (error_file)
fprintf(error_file,
"PC = 0x%x, Invalid instruction address",
s->pc);
return STAT_INS;
}
if (!reg_valid(lo1)) {
if (error_file)
fprintf(error_file,
"PC = 0x%x, Invalid register ID 0x%.1x\n",
s->pc, lo1);
return STAT_INS;
}
argB = get_reg_val(s->r, lo1);
val = argB + cval;
set_reg_val(s->r, lo1, val);
s->cc = compute_cc(A_ADD, cval, argB);
s->pc = ftpc;
break;
case I_ISUBL:
if (!ok1) {
if (error_file)
fprintf(error_file,
"PC = 0x%x, Invalid instruction address\n", s->pc);
return STAT_ADR;
}
if (!okc) {
if (error_file)
fprintf(error_file,
"PC = 0x%x, Invalid instruction address",
s->pc);
return STAT_INS;
}
if (!reg_valid(lo1)) {
if (error_file)
fprintf(error_file,
"PC = 0x%x, Invalid register ID 0x%.1x\n",
s->pc, lo1);
return STAT_INS;
}
argB = get_reg_val(s->r, lo1);
val = argB - cval;
set_reg_val(s->r, lo1, val);
s->cc = compute_cc(A_SUB, cval, argB);
s->pc = ftpc;
break;
default:
if (error_file)
fprintf(error_file,
"PC = 0x%x, Invalid instruction %.2x\n", s->pc, byte0);
return STAT_INS;
}
return STAT_AOK;
}
/* Return resulting status */
static byte_t sim_step()
{
word_t aluA;
word_t aluB;
word_t alufun;
status = STAT_AOK;
imem_error = dmem_error = FALSE;
update_state(); /* Update state from last cycle */
if (plusmode) {
pc = gen_pc();
}
valp = pc;
instr = HPACK(I_NOP, F_NONE);
imem_error = !get_byte_val(mem, valp, &instr);
if (imem_error) {
sim_log("Couldn't fetch at address 0x%x\n", valp);
}
imem_icode = HI4(instr);
imem_ifun = LO4(instr);
icode = gen_icode();
ifun = gen_ifun();
instr_valid = gen_instr_valid();
valp++;
if (gen_need_regids()) {
byte_t regids;
if (get_byte_val(mem, valp, ®ids)) {
ra = GET_RA(regids);
rb = GET_RB(regids);
} else {
ra = REG_NONE;
rb = REG_NONE;
status = STAT_ADR;
sim_log("Couldn't fetch at address 0x%x\n", valp);
}
valp++;
} else {
ra = REG_NONE;
rb = REG_NONE;
}
if (gen_need_valC()) {
if (get_word_val(mem, valp, &valc)) {
} else {
valc = 0;
status = STAT_ADR;
sim_log("Couldn't fetch at address 0x%x\n", valp);
}
valp+=4;
} else {
valc = 0;
}
sim_log("IF: Fetched %s at 0x%x. ra=%s, rb=%s, valC = 0x%x\n",
iname(HPACK(icode,ifun)), pc, reg_name(ra), reg_name(rb), valc);
if (status == STAT_AOK && icode == I_HALT) {
status = STAT_HLT;
}
srcA = gen_srcA();
if (srcA != REG_NONE) {
vala = get_reg_val(reg, srcA);
} else {
vala = 0;
}
srcB = gen_srcB();
if (srcB != REG_NONE) {
valb = get_reg_val(reg, srcB);
} else {
valb = 0;
}
cond = cond_holds(cc, ifun);
destE = gen_dstE();
destM = gen_dstM();
aluA = gen_aluA();
aluB = gen_aluB();
alufun = gen_alufun();
vale = compute_alu(alufun, aluA, aluB);
cc_in = cc;
if (gen_set_cc())
cc_in = compute_cc(alufun, aluA, aluB);
bcond = cond && (icode == I_JMP);
mem_addr = gen_mem_addr();
mem_data = gen_mem_data();
if (gen_mem_read()) {
dmem_error = dmem_error || !get_word_val(mem, mem_addr, &valm);
if (dmem_error) {
sim_log("Couldn't read at address 0x%x\n", mem_addr);
}
} else
valm = 0;
mem_write = gen_mem_write();
if (mem_write) {
/* Do a test read of the data memory to make sure address is OK */
word_t junk;
dmem_error = dmem_error || !get_word_val(mem, mem_addr, &junk);
}
status = gen_Stat();
if (plusmode) {
prev_icode_in = icode;
prev_ifun_in = ifun;
prev_valc_in = valc;
prev_valm_in = valm;
prev_valp_in = valp;
prev_bcond_in = bcond;
} else {
/* Update PC */
pc_in = gen_new_pc();
}
sim_report();
return status;
}