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emul/8086: a little bit of cleanup in cpu.c

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De-macroisation negatively impacts speed, but this emulator doesn't
need to be fast. Clear code is more important.
This commit is contained in:
Virgil Dupras 2020-10-25 14:25:12 -04:00
parent 8760766bb4
commit 44abcaa8f8
1 changed files with 67 additions and 94 deletions
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161
emul/8086/cpu.c
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@ -33,64 +33,6 @@
#define getreg8(regid) regs.byteregs[byteregtable[regid]] #define getreg8(regid) regs.byteregs[byteregtable[regid]]
#define putreg8(regid, writeval) regs.byteregs[byteregtable[regid]] = writeval #define putreg8(regid, writeval) regs.byteregs[byteregtable[regid]] = writeval
#define makeflagsword() \
( \
2 | (uint16_t) cf | ((uint16_t) pf << 2) | ((uint16_t) af << 4) | ((uint16_t) zf << 6) | ((uint16_t) sf << 7) | \
((uint16_t) tf << 8) | ((uint16_t) ifl << 9) | ((uint16_t) df << 10) | ((uint16_t) of << 11) \
)
#define decodeflagsword(x) { \
temp16 = x; \
cf = temp16 & 1; \
pf = (temp16 >> 2) & 1; \
af = (temp16 >> 4) & 1; \
zf = (temp16 >> 6) & 1; \
sf = (temp16 >> 7) & 1; \
tf = (temp16 >> 8) & 1; \
ifl = (temp16 >> 9) & 1; \
df = (temp16 >> 10) & 1; \
of = (temp16 >> 11) & 1; \
}
#define modregrm() { \
addrbyte = getmem8(segregs[regcs], ip); \
StepIP(1); \
mode = addrbyte >> 6; \
reg = (addrbyte >> 3) & 7; \
rm = addrbyte & 7; \
switch(mode) \
{ \
case 0: \
if(rm == 6) { \
disp16 = getmem16(segregs[regcs], ip); \
StepIP(2); \
} \
if(((rm == 2) || (rm == 3)) && !segoverride) { \
useseg = segregs[regss]; \
} \
break; \
\
case 1: \
disp16 = signext(getmem8(segregs[regcs], ip)); \
StepIP(1); \
if(((rm == 2) || (rm == 3) || (rm == 6)) && !segoverride) { \
useseg = segregs[regss]; \
} \
break; \
\
case 2: \
disp16 = getmem16(segregs[regcs], ip); \
StepIP(2); \
if(((rm == 2) || (rm == 3) || (rm == 6)) && !segoverride) { \
useseg = segregs[regss]; \
} \
break; \
\
default: \
disp8 = 0; \
disp16 = 0; \
} \
}
uint8_t byteregtable[8] = { regal, regcl, regdl, regbl, regah, regch, regdh, regbh }; uint8_t byteregtable[8] = { regal, regcl, regdl, regbl, regah, regch, regdh, regbh };
static const uint8_t parity[0x100] = { static const uint8_t parity[0x100] = {
@ -107,12 +49,11 @@ static const uint8_t parity[0x100] = {
uint8_t RAM[0x100000]; uint8_t RAM[0x100000];
INTHOOK INTHOOKS[0x100] = {0}; INTHOOK INTHOOKS[0x100] = {0};
uint8_t opcode, segoverride, reptype, hltstate = 0; uint8_t opcode, segoverride, reptype, hltstate = 0;
uint16_t segregs[4], savecs, saveip, ip, useseg, oldsp; uint16_t segregs[4], ip, useseg, oldsp;
uint8_t tempcf, oldcf, cf, pf, af, zf, sf, tf, ifl, df, of, mode, reg, rm; uint8_t tempcf, cf, pf, af, zf, sf, tf, ifl, df, of, mode, reg, rm;
uint16_t oper1, oper2, res16, disp16, temp16, dummy, stacksize, frametemp; uint16_t oper1, oper2, res16, disp16, temp16, stacksize, frametemp;
uint8_t oper1b, oper2b, res8, disp8, temp8, nestlev, addrbyte; uint8_t oper1b, oper2b, res8, disp8, nestlev, addrbyte;
uint32_t temp1, temp2, temp3, temp4, temp5, temp32, tempaddr32, ea; uint32_t temp1, temp2, temp3, ea;
uint64_t totalexec;
union _bytewordregs_ regs; union _bytewordregs_ regs;
@ -126,8 +67,7 @@ static uint8_t portin (uint16_t portnum) { return 0; }
static uint16_t portin16 (uint16_t portnum) { return 0; } static uint16_t portin16 (uint16_t portnum) { return 0; }
void write86 (uint32_t addr32, uint8_t value) { void write86 (uint32_t addr32, uint8_t value) {
tempaddr32 = addr32 & 0xFFFFF; RAM[addr32 & 0xFFFFF] = value;
RAM[tempaddr32] = value;
} }
void writew86 (uint32_t addr32, uint16_t value) { void writew86 (uint32_t addr32, uint16_t value) {
@ -1169,19 +1109,71 @@ void intcall86(uint8_t intnum) {
return; return;
} }
fprintf(stderr, "Unknown INT called: %x\n", intnum); fprintf(stderr, "Unknown INT called: %x\n", intnum);
/*push (makeflagsword() ); }
push (segregs[regcs]);
push (ip); uint16_t makeflagsword() {
segregs[regcs] = getmem16 (0, (uint16_t) intnum * 4 + 2); return 2 | (uint16_t) cf | ((uint16_t) pf << 2) | ((uint16_t) af << 4) | \
ip = getmem16 (0, (uint16_t) intnum * 4); ((uint16_t) zf << 6) | ((uint16_t) sf << 7) | ((uint16_t) tf << 8) | \
ifl = 0; ((uint16_t) ifl << 9) | ((uint16_t) df << 10) | ((uint16_t) of << 11);
tf = 0;*/ }
void decodeflagsword(uint16_t x) {
cf = x & 1;
pf = (x >> 2) & 1;
af = (x >> 4) & 1;
zf = (x >> 6) & 1;
sf = (x >> 7) & 1;
tf = (x >> 8) & 1;
ifl = (x >> 9) & 1;
df = (x >> 10) & 1;
of = (x >> 11) & 1;
}
static void modregrm() {
addrbyte = getmem8(segregs[regcs], ip);
StepIP(1);
mode = addrbyte >> 6;
reg = (addrbyte >> 3) & 7;
rm = addrbyte & 7;
switch(mode)
{
case 0:
if (rm == 6) {
disp16 = getmem16(segregs[regcs], ip);
StepIP(2);
}
if (((rm == 2) || (rm == 3)) && !segoverride) {
useseg = segregs[regss];
}
break;
case 1:
disp16 = signext(getmem8(segregs[regcs], ip));
StepIP(1);
if (((rm == 2) || (rm == 3) || (rm == 6)) && !segoverride) {
useseg = segregs[regss];
}
break;
case 2:
disp16 = getmem16(segregs[regcs], ip);
StepIP(2);
if (((rm == 2) || (rm == 3) || (rm == 6)) && !segoverride) {
useseg = segregs[regss];
}
break;
default:
disp8 = 0;
disp16 = 0;
}
} }
int exec86(int execloops) { int exec86(int execloops) {
int loopcount; int loopcount;
uint8_t docontinue; uint8_t docontinue;
static uint16_t firstip; static uint16_t firstip;
uint16_t oldcf;
for (loopcount = 0; loopcount < execloops; loopcount++) { for (loopcount = 0; loopcount < execloops; loopcount++) {
if (hltstate) return 0; if (hltstate) return 0;
@ -1195,8 +1187,6 @@ int exec86(int execloops) {
while (!docontinue) { while (!docontinue) {
segregs[regcs] = segregs[regcs] & 0xFFFF; segregs[regcs] = segregs[regcs] & 0xFFFF;
ip = ip & 0xFFFF; ip = ip & 0xFFFF;
savecs = segregs[regcs];
saveip = ip;
opcode = getmem8 (segregs[regcs], ip); opcode = getmem8 (segregs[regcs], ip);
StepIP (1); StepIP (1);
@ -1237,8 +1227,6 @@ int exec86(int execloops) {
} }
} }
totalexec++;
switch (opcode) { switch (opcode) {
case 0x0: /* 00 ADD Eb Gb */ case 0x0: /* 00 ADD Eb Gb */
modregrm(); modregrm();
@ -1962,7 +1950,7 @@ int exec86(int execloops) {
regs.wordregs[regdi] = pop(); regs.wordregs[regdi] = pop();
regs.wordregs[regsi] = pop(); regs.wordregs[regsi] = pop();
regs.wordregs[regbp] = pop(); regs.wordregs[regbp] = pop();
dummy = pop(); pop();
regs.wordregs[regbx] = pop(); regs.wordregs[regbx] = pop();
regs.wordregs[regdx] = pop(); regs.wordregs[regdx] = pop();
regs.wordregs[regcx] = pop(); regs.wordregs[regcx] = pop();
@ -2062,7 +2050,6 @@ int exec86(int execloops) {
regs.wordregs[regcx] = regs.wordregs[regcx] - 1; regs.wordregs[regcx] = regs.wordregs[regcx] - 1;
} }
totalexec++;
loopcount++; loopcount++;
if (!reptype) { if (!reptype) {
break; break;
@ -2090,7 +2077,6 @@ int exec86(int execloops) {
regs.wordregs[regcx] = regs.wordregs[regcx] - 1; regs.wordregs[regcx] = regs.wordregs[regcx] - 1;
} }
totalexec++;
loopcount++; loopcount++;
if (!reptype) { if (!reptype) {
break; break;
@ -2118,7 +2104,6 @@ int exec86(int execloops) {
regs.wordregs[regcx] = regs.wordregs[regcx] - 1; regs.wordregs[regcx] = regs.wordregs[regcx] - 1;
} }
totalexec++;
loopcount++; loopcount++;
if (!reptype) { if (!reptype) {
break; break;
@ -2146,7 +2131,6 @@ int exec86(int execloops) {
regs.wordregs[regcx] = regs.wordregs[regcx] - 1; regs.wordregs[regcx] = regs.wordregs[regcx] - 1;
} }
totalexec++;
loopcount++; loopcount++;
if (!reptype) { if (!reptype) {
break; break;
@ -2522,8 +2506,7 @@ int exec86(int execloops) {
break; break;
case 0x9D: /* 9D POPF */ case 0x9D: /* 9D POPF */
temp16 = pop(); decodeflagsword (pop());
decodeflagsword (temp16);
break; break;
case 0x9E: /* 9E SAHF */ case 0x9E: /* 9E SAHF */
@ -2574,7 +2557,6 @@ int exec86(int execloops) {
regs.wordregs[regcx] = regs.wordregs[regcx] - 1; regs.wordregs[regcx] = regs.wordregs[regcx] - 1;
} }
totalexec++;
loopcount++; loopcount++;
if (!reptype) { if (!reptype) {
break; break;
@ -2602,7 +2584,6 @@ int exec86(int execloops) {
regs.wordregs[regcx] = regs.wordregs[regcx] - 1; regs.wordregs[regcx] = regs.wordregs[regcx] - 1;
} }
totalexec++;
loopcount++; loopcount++;
if (!reptype) { if (!reptype) {
break; break;
@ -2639,7 +2620,6 @@ int exec86(int execloops) {
break; break;
} }
totalexec++;
loopcount++; loopcount++;
if (!reptype) { if (!reptype) {
break; break;
@ -2677,7 +2657,6 @@ int exec86(int execloops) {
break; break;
} }
totalexec++;
loopcount++; loopcount++;
if (!reptype) { if (!reptype) {
break; break;
@ -2717,7 +2696,6 @@ int exec86(int execloops) {
regs.wordregs[regcx] = regs.wordregs[regcx] - 1; regs.wordregs[regcx] = regs.wordregs[regcx] - 1;
} }
totalexec++;
loopcount++; loopcount++;
if (!reptype) { if (!reptype) {
break; break;
@ -2743,7 +2721,6 @@ int exec86(int execloops) {
regs.wordregs[regcx] = regs.wordregs[regcx] - 1; regs.wordregs[regcx] = regs.wordregs[regcx] - 1;
} }
totalexec++;
loopcount++; loopcount++;
if (!reptype) { if (!reptype) {
break; break;
@ -2769,7 +2746,6 @@ int exec86(int execloops) {
regs.wordregs[regcx] = regs.wordregs[regcx] - 1; regs.wordregs[regcx] = regs.wordregs[regcx] - 1;
} }
totalexec++;
loopcount++; loopcount++;
if (!reptype) { if (!reptype) {
break; break;
@ -2796,7 +2772,6 @@ int exec86(int execloops) {
regs.wordregs[regcx] = regs.wordregs[regcx] - 1; regs.wordregs[regcx] = regs.wordregs[regcx] - 1;
} }
totalexec++;
loopcount++; loopcount++;
if (!reptype) { if (!reptype) {
break; break;
@ -2831,7 +2806,6 @@ int exec86(int execloops) {
break; break;
} }
totalexec++;
loopcount++; loopcount++;
if (!reptype) { if (!reptype) {
break; break;
@ -2866,7 +2840,6 @@ int exec86(int execloops) {
break; break;
} }
totalexec++;
loopcount++; loopcount++;
if (!reptype) { if (!reptype) {
break; break;