From 44abcaa8f8fe93aec9c44b9ab5f845400923eff7 Mon Sep 17 00:00:00 2001 From: Virgil Dupras Date: Sun, 25 Oct 2020 14:25:12 -0400 Subject: [PATCH] emul/8086: a little bit of cleanup in cpu.c De-macroisation negatively impacts speed, but this emulator doesn't need to be fast. Clear code is more important. --- emul/8086/cpu.c | 161 ++++++++++++++++++++---------------------------- 1 file changed, 67 insertions(+), 94 deletions(-) diff --git a/emul/8086/cpu.c b/emul/8086/cpu.c index 3b66be5..6201715 100755 --- a/emul/8086/cpu.c +++ b/emul/8086/cpu.c @@ -33,64 +33,6 @@ #define getreg8(regid) regs.byteregs[byteregtable[regid]] #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 }; static const uint8_t parity[0x100] = { @@ -107,12 +49,11 @@ static const uint8_t parity[0x100] = { uint8_t RAM[0x100000]; INTHOOK INTHOOKS[0x100] = {0}; uint8_t opcode, segoverride, reptype, hltstate = 0; -uint16_t segregs[4], savecs, saveip, ip, useseg, oldsp; -uint8_t tempcf, oldcf, cf, pf, af, zf, sf, tf, ifl, df, of, mode, reg, rm; -uint16_t oper1, oper2, res16, disp16, temp16, dummy, stacksize, frametemp; -uint8_t oper1b, oper2b, res8, disp8, temp8, nestlev, addrbyte; -uint32_t temp1, temp2, temp3, temp4, temp5, temp32, tempaddr32, ea; -uint64_t totalexec; +uint16_t segregs[4], ip, useseg, oldsp; +uint8_t tempcf, cf, pf, af, zf, sf, tf, ifl, df, of, mode, reg, rm; +uint16_t oper1, oper2, res16, disp16, temp16, stacksize, frametemp; +uint8_t oper1b, oper2b, res8, disp8, nestlev, addrbyte; +uint32_t temp1, temp2, temp3, ea; 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; } void write86 (uint32_t addr32, uint8_t value) { - tempaddr32 = addr32 & 0xFFFFF; - RAM[tempaddr32] = value; + RAM[addr32 & 0xFFFFF] = value; } void writew86 (uint32_t addr32, uint16_t value) { @@ -1169,19 +1109,71 @@ void intcall86(uint8_t intnum) { return; } fprintf(stderr, "Unknown INT called: %x\n", intnum); - /*push (makeflagsword() ); - push (segregs[regcs]); - push (ip); - segregs[regcs] = getmem16 (0, (uint16_t) intnum * 4 + 2); - ip = getmem16 (0, (uint16_t) intnum * 4); - ifl = 0; - tf = 0;*/ +} + +uint16_t makeflagsword() { + return 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); +} + +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 loopcount; uint8_t docontinue; static uint16_t firstip; + uint16_t oldcf; for (loopcount = 0; loopcount < execloops; loopcount++) { if (hltstate) return 0; @@ -1195,8 +1187,6 @@ int exec86(int execloops) { while (!docontinue) { segregs[regcs] = segregs[regcs] & 0xFFFF; ip = ip & 0xFFFF; - savecs = segregs[regcs]; - saveip = ip; opcode = getmem8 (segregs[regcs], ip); StepIP (1); @@ -1237,8 +1227,6 @@ int exec86(int execloops) { } } - totalexec++; - switch (opcode) { case 0x0: /* 00 ADD Eb Gb */ modregrm(); @@ -1962,7 +1950,7 @@ int exec86(int execloops) { regs.wordregs[regdi] = pop(); regs.wordregs[regsi] = pop(); regs.wordregs[regbp] = pop(); - dummy = pop(); + pop(); regs.wordregs[regbx] = pop(); regs.wordregs[regdx] = pop(); regs.wordregs[regcx] = pop(); @@ -2062,7 +2050,6 @@ int exec86(int execloops) { regs.wordregs[regcx] = regs.wordregs[regcx] - 1; } - totalexec++; loopcount++; if (!reptype) { break; @@ -2090,7 +2077,6 @@ int exec86(int execloops) { regs.wordregs[regcx] = regs.wordregs[regcx] - 1; } - totalexec++; loopcount++; if (!reptype) { break; @@ -2118,7 +2104,6 @@ int exec86(int execloops) { regs.wordregs[regcx] = regs.wordregs[regcx] - 1; } - totalexec++; loopcount++; if (!reptype) { break; @@ -2146,7 +2131,6 @@ int exec86(int execloops) { regs.wordregs[regcx] = regs.wordregs[regcx] - 1; } - totalexec++; loopcount++; if (!reptype) { break; @@ -2522,8 +2506,7 @@ int exec86(int execloops) { break; case 0x9D: /* 9D POPF */ - temp16 = pop(); - decodeflagsword (temp16); + decodeflagsword (pop()); break; case 0x9E: /* 9E SAHF */ @@ -2574,7 +2557,6 @@ int exec86(int execloops) { regs.wordregs[regcx] = regs.wordregs[regcx] - 1; } - totalexec++; loopcount++; if (!reptype) { break; @@ -2602,7 +2584,6 @@ int exec86(int execloops) { regs.wordregs[regcx] = regs.wordregs[regcx] - 1; } - totalexec++; loopcount++; if (!reptype) { break; @@ -2639,7 +2620,6 @@ int exec86(int execloops) { break; } - totalexec++; loopcount++; if (!reptype) { break; @@ -2677,7 +2657,6 @@ int exec86(int execloops) { break; } - totalexec++; loopcount++; if (!reptype) { break; @@ -2717,7 +2696,6 @@ int exec86(int execloops) { regs.wordregs[regcx] = regs.wordregs[regcx] - 1; } - totalexec++; loopcount++; if (!reptype) { break; @@ -2743,7 +2721,6 @@ int exec86(int execloops) { regs.wordregs[regcx] = regs.wordregs[regcx] - 1; } - totalexec++; loopcount++; if (!reptype) { break; @@ -2769,7 +2746,6 @@ int exec86(int execloops) { regs.wordregs[regcx] = regs.wordregs[regcx] - 1; } - totalexec++; loopcount++; if (!reptype) { break; @@ -2796,7 +2772,6 @@ int exec86(int execloops) { regs.wordregs[regcx] = regs.wordregs[regcx] - 1; } - totalexec++; loopcount++; if (!reptype) { break; @@ -2831,7 +2806,6 @@ int exec86(int execloops) { break; } - totalexec++; loopcount++; if (!reptype) { break; @@ -2866,7 +2840,6 @@ int exec86(int execloops) { break; } - totalexec++; loopcount++; if (!reptype) { break;