diff options
| author | aiju <devnull@localhost> | 2014-02-20 23:22:14 +0100 |
|---|---|---|
| committer | aiju <devnull@localhost> | 2014-02-20 23:22:14 +0100 |
| commit | eeac553c36e1cb1d7786115d7202bfe732deb54e (patch) | |
| tree | 1eecc9e02649526248006476fda7ad4030e2a6a4 /sys/src/games/nes/cpu.c | |
| parent | 9c40e15ba8ae000f73c23d89143d6c44b75220fd (diff) | |
games/nes: bug fixing
Diffstat (limited to 'sys/src/games/nes/cpu.c')
| -rw-r--r-- | sys/src/games/nes/cpu.c | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/sys/src/games/nes/cpu.c b/sys/src/games/nes/cpu.c index 1377cf2fd..c1624c02f 100644 --- a/sys/src/games/nes/cpu.c +++ b/sys/src/games/nes/cpu.c @@ -6,6 +6,7 @@ u16int pc, curpc; u8int rA, rX, rY, rS, rP; int nmi; +extern int map; static u8int fetch8(void) @@ -172,7 +173,13 @@ dec(u16int a) static void inc(u16int a) { - memwrite(a, nz(memread(a) + 1)); + u8int v; + + v = memread(a); + memwrite(a, v); + v = nz(v + 1); + if(!(map == 1 && a >= 0x8000)) + memwrite(a, v); } static void @@ -229,6 +236,8 @@ interrupt(int nmi, int brk) rP |= FLAGI; } +int trace; + int step(void) { @@ -243,6 +252,8 @@ step(void) } curpc = pc; op = fetch8(); + if(trace) + print("%x %x %x %x %x %x %x %x\n", curpc, op, rA, rX, rY, rS, rP, memread(0x2c)); switch(op){ case 0x00: pc++; interrupt(0, 1); return 7; case 0x01: nz(rA |= indX()); return 6; @@ -397,12 +408,12 @@ step(void) case 0xC5: cmp(rA, zp()); return 3; case 0xC9: cmp(rA, imm()); return 2; case 0xCD: cmp(rA, abso()); return 4; + case 0xD0: if((rP & FLAGZ) == 0) return branch(); pc++; return 3; case 0xD1: cmp(rA, indY(&c)); return 5 + c; case 0xD5: cmp(rA, zpX()); return 4; case 0xD8: rP &= ~FLAGD; return 2; case 0xD9: cmp(rA, absY()); return 4 + ((u8int)a < rY); case 0xDD: cmp(rA, absX()); return 4 + ((u8int)a < rX); - case 0xD0: if((rP & FLAGZ) == 0) return branch(); pc++; return 3; case 0xC0: cmp(rY, imm()); return 2; case 0xC4: cmp(rY, zp()); return 3; case 0xC6: dec(fetch8()); return 5; |