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implement all of the nestest unofficial opcodes and fix branch cycles

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This commit is contained in:
Vineet K 2024-07-04 15:06:15 -04:00
parent 4ccf9f5cee
commit e1cdd73868
3 changed files with 46 additions and 45 deletions
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19
cpu.c
View File

@ -127,9 +127,7 @@ opcode_mem(enum addressing_mode mode)
val = (arg + regs.y) % 256; val = (arg + regs.y) % 256;
break; break;
case AM_REL: case AM_REL:
val = arg + regs.pc; val = (int8_t)arg + regs.pc;
if (((regs.pc + 1) & 0xFF00) != (val & 0xFF00))
val -= 0x0100;
break; break;
case AM_IMM: case AM_IMM:
case AM_ABS: case AM_ABS:
@ -174,6 +172,9 @@ branch(uint16_t addr, bool cond)
return; return;
cycles++; cycles++;
if (((regs.pc + 1) & 0xFF00) != (addr & 0xFF00))
cycles++;
regs.pc = addr; regs.pc = addr;
} }
@ -277,7 +278,7 @@ BRK(uint16_t arg)
{ {
/* TODO: push regs.pc and regs.status to stack and load IRQ vector */ /* TODO: push regs.pc and regs.status to stack and load IRQ vector */
regs.status.brk = 1; regs.status.brk = 1;
// exit(0); exit(0);
} }
void void
@ -771,11 +772,11 @@ DCP(uint16_t arg)
memwrite(arg, tmp); memwrite(arg, tmp);
regs.status.carry = tmp <= regs.a; regs.status.carry = tmp <= regs.a;
STATUS_UPDATE_NZ(tmp); STATUS_UPDATE_NZ(regs.a - tmp);
} }
void void
ISC(uint16_t arg) ISB(uint16_t arg)
{ {
INC(arg); INC(arg);
SBC(peek(arg)); SBC(peek(arg));
@ -807,7 +808,7 @@ void
RLA(uint16_t arg) RLA(uint16_t arg)
{ {
ROL(arg); ROL(arg);
AND(arg); AND(peek(arg));
} }
void void
@ -821,14 +822,14 @@ void
SLO(uint16_t arg) SLO(uint16_t arg)
{ {
ASL(arg); ASL(arg);
ORA(arg); ORA(peek(arg));
} }
void void
SRE(uint16_t arg) SRE(uint16_t arg)
{ {
LSR(arg); LSR(arg);
EOR(arg); EOR(peek(arg));
} }
void void

2
cpu.h
View File

@ -72,7 +72,7 @@ void AXA(uint16_t arg);
void AXS(uint16_t arg); void AXS(uint16_t arg);
void DCP(uint16_t arg); void DCP(uint16_t arg);
void DOP(uint16_t arg); void DOP(uint16_t arg);
void ISC(uint16_t arg); void ISB(uint16_t arg);
void KIL(uint16_t arg); void KIL(uint16_t arg);
void LAR(uint16_t arg); void LAR(uint16_t arg);
void LAX(uint16_t arg); void LAX(uint16_t arg);

70
opcodes.h
View File

@ -220,13 +220,13 @@ struct opcode opcodes[0x100] = {
[0xD4] = { "NOP", NOP, 2, 4, true, false, false, true, AM_ZP_X }, [0xD4] = { "NOP", NOP, 2, 4, true, false, false, true, AM_ZP_X },
[0xE2] = { "NOP", NOP, 2, 2, false, false, false, true, AM_IMM }, [0xE2] = { "NOP", NOP, 2, 2, false, false, false, true, AM_IMM },
[0xF4] = { "NOP", NOP, 2, 4, true, false, false, true, AM_ZP_X }, [0xF4] = { "NOP", NOP, 2, 4, true, false, false, true, AM_ZP_X },
[0xE7] = { "ISC", ISC, 2, 5, false, false, false, true, AM_ZP }, [0xE7] = { "ISB", ISB, 2, 5, false, true, false, true, AM_ZP },
[0xF7] = { "ISC", ISC, 2, 6, false, false, false, true, AM_ZP_X }, [0xF7] = { "ISB", ISB, 2, 6, false, true, false, true, AM_ZP_X },
[0xEF] = { "ISC", ISC, 3, 6, false, false, false, true, AM_ABS }, [0xEF] = { "ISB", ISB, 3, 6, false, true, false, true, AM_ABS },
[0xFF] = { "ISC", ISC, 3, 7, false, false, false, true, AM_ABS_X }, [0xFF] = { "ISB", ISB, 3, 7, false, true, false, true, AM_ABS_X },
[0xFB] = { "ISC", ISC, 3, 7, false, false, false, true, AM_ABS_Y }, [0xFB] = { "ISB", ISB, 3, 7, false, true, false, true, AM_ABS_Y },
[0xE3] = { "ISC", ISC, 2, 8, false, false, false, true, AM_IND_X }, [0xE3] = { "ISB", ISB, 2, 8, false, true, false, true, AM_IND_X },
[0xF3] = { "ISC", ISC, 2, 8, false, false, false, true, AM_IND_Y }, [0xF3] = { "ISB", ISB, 2, 8, false, true, false, true, AM_IND_Y },
[0x02] = { "KIL", KIL, 1, 0, false, false, false, true, AM_NONE }, [0x02] = { "KIL", KIL, 1, 0, false, false, false, true, AM_NONE },
[0x12] = { "KIL", KIL, 1, 0, false, false, false, true, AM_NONE }, [0x12] = { "KIL", KIL, 1, 0, false, false, false, true, AM_NONE },
[0x22] = { "KIL", KIL, 1, 0, false, false, false, true, AM_NONE }, [0x22] = { "KIL", KIL, 1, 0, false, false, false, true, AM_NONE },
@ -252,35 +252,35 @@ struct opcode opcodes[0x100] = {
[0x7A] = { "NOP", NOP, 1, 2, false, false, false, true, AM_NONE }, [0x7A] = { "NOP", NOP, 1, 2, false, false, false, true, AM_NONE },
[0xDA] = { "NOP", NOP, 1, 2, false, false, false, true, AM_NONE }, [0xDA] = { "NOP", NOP, 1, 2, false, false, false, true, AM_NONE },
[0xFA] = { "NOP", NOP, 1, 2, false, false, false, true, AM_NONE }, [0xFA] = { "NOP", NOP, 1, 2, false, false, false, true, AM_NONE },
[0x27] = { "RLA", RLA, 2, 5, true, true, false, true, AM_ZP }, [0x27] = { "RLA", RLA, 2, 5, false, true, false, true, AM_ZP },
[0x37] = { "RLA", RLA, 2, 6, true, true, false, true, AM_ZP_X }, [0x37] = { "RLA", RLA, 2, 6, false, true, false, true, AM_ZP_X },
[0x2F] = { "RLA", RLA, 3, 6, true, true, false, true, AM_ABS }, [0x2F] = { "RLA", RLA, 3, 6, false, true, false, true, AM_ABS },
[0x3F] = { "RLA", RLA, 3, 7, true, true, false, true, AM_ABS_X }, [0x3F] = { "RLA", RLA, 3, 7, false, true, false, true, AM_ABS_X },
[0x3B] = { "RLA", RLA, 3, 7, true, true, false, true, AM_ABS_Y }, [0x3B] = { "RLA", RLA, 3, 7, false, true, false, true, AM_ABS_Y },
[0x23] = { "RLA", RLA, 2, 8, true, true, false, true, AM_IND_X }, [0x23] = { "RLA", RLA, 2, 8, false, true, false, true, AM_IND_X },
[0x33] = { "RLA", RLA, 2, 8, true, true, false, true, AM_IND_Y }, [0x33] = { "RLA", RLA, 2, 8, false, true, false, true, AM_IND_Y },
[0x67] = { "RRA", RRA, 2, 5, true, true, false, true, AM_ZP }, [0x67] = { "RRA", RRA, 2, 5, false, true, false, true, AM_ZP },
[0x77] = { "RRA", RRA, 2, 6, true, true, false, true, AM_ZP_X }, [0x77] = { "RRA", RRA, 2, 6, false, true, false, true, AM_ZP_X },
[0x6F] = { "RRA", RRA, 3, 6, true, true, false, true, AM_ABS }, [0x6F] = { "RRA", RRA, 3, 6, false, true, false, true, AM_ABS },
[0x7F] = { "RRA", RRA, 3, 7, true, true, false, true, AM_ABS_X }, [0x7F] = { "RRA", RRA, 3, 7, false, true, false, true, AM_ABS_X },
[0x7B] = { "RRA", RRA, 3, 7, true, true, false, true, AM_ABS_Y }, [0x7B] = { "RRA", RRA, 3, 7, false, true, false, true, AM_ABS_Y },
[0x63] = { "RRA", RRA, 2, 8, true, true, false, true, AM_IND_X }, [0x63] = { "RRA", RRA, 2, 8, false, true, false, true, AM_IND_X },
[0x73] = { "RRA", RRA, 2, 8, true, true, false, true, AM_IND_Y }, [0x73] = { "RRA", RRA, 2, 8, false, true, false, true, AM_IND_Y },
[0xEB] = { "SBC", SBC, 2, 2, false, false, false, true, AM_IMM }, [0xEB] = { "SBC", SBC, 2, 2, false, false, false, true, AM_IMM },
[0x07] = { "SLO", SLO, 2, 5, true, true, false, true, AM_ZP }, [0x07] = { "SLO", SLO, 2, 5, false, true, false, true, AM_ZP },
[0x17] = { "SLO", SLO, 2, 6, true, true, false, true, AM_ZP_X }, [0x17] = { "SLO", SLO, 2, 6, false, true, false, true, AM_ZP_X },
[0x0F] = { "SLO", SLO, 3, 6, true, true, false, true, AM_ABS }, [0x0F] = { "SLO", SLO, 3, 6, false, true, false, true, AM_ABS },
[0x1F] = { "SLO", SLO, 3, 7, true, true, false, true, AM_ABS_X }, [0x1F] = { "SLO", SLO, 3, 7, false, true, false, true, AM_ABS_X },
[0x1B] = { "SLO", SLO, 3, 7, true, true, false, true, AM_ABS_Y }, [0x1B] = { "SLO", SLO, 3, 7, false, true, false, true, AM_ABS_Y },
[0x03] = { "SLO", SLO, 2, 8, true, true, false, true, AM_IND_X }, [0x03] = { "SLO", SLO, 2, 8, false, true, false, true, AM_IND_X },
[0x13] = { "SLO", SLO, 2, 8, true, true, false, true, AM_IND_Y }, [0x13] = { "SLO", SLO, 2, 8, false, true, false, true, AM_IND_Y },
[0x47] = { "SRE", SRE, 2, 5, true, true, false, true, AM_ZP }, [0x47] = { "SRE", SRE, 2, 5, false, true, false, true, AM_ZP },
[0x57] = { "SRE", SRE, 2, 6, true, true, false, true, AM_ZP_X }, [0x57] = { "SRE", SRE, 2, 6, false, true, false, true, AM_ZP_X },
[0x4F] = { "SRE", SRE, 3, 6, true, true, false, true, AM_ABS }, [0x4F] = { "SRE", SRE, 3, 6, false, true, false, true, AM_ABS },
[0x5F] = { "SRE", SRE, 3, 7, true, true, false, true, AM_ABS_X }, [0x5F] = { "SRE", SRE, 3, 7, false, true, false, true, AM_ABS_X },
[0x5B] = { "SRE", SRE, 3, 7, true, true, false, true, AM_ABS_Y }, [0x5B] = { "SRE", SRE, 3, 7, false, true, false, true, AM_ABS_Y },
[0x43] = { "SRE", SRE, 2, 8, true, true, false, true, AM_IND_X }, [0x43] = { "SRE", SRE, 2, 8, false, true, false, true, AM_IND_X },
[0x53] = { "SRE", SRE, 2, 8, true, true, false, true, AM_IND_Y }, [0x53] = { "SRE", SRE, 2, 8, false, true, false, true, AM_IND_Y },
[0x9E] = { "SXA", SXA, 3, 5, false, true, false, true, AM_ABS_Y }, [0x9E] = { "SXA", SXA, 3, 5, false, true, false, true, AM_ABS_Y },
[0x9C] = { "SYA", SYA, 3, 5, false, true, false, true, AM_ABS_X }, [0x9C] = { "SYA", SYA, 3, 5, false, true, false, true, AM_ABS_X },
[0x0C] = { "NOP", NOP, 3, 4, true, false, false, true, AM_ABS }, [0x0C] = { "NOP", NOP, 3, 4, true, false, false, true, AM_ABS },