diff options
Diffstat (limited to 'src/cpu/6502.c')
| -rw-r--r-- | src/cpu/6502.c | 50 |
1 files changed, 8 insertions, 42 deletions
diff --git a/src/cpu/6502.c b/src/cpu/6502.c index 595cd4e..7ae3f16 100644 --- a/src/cpu/6502.c +++ b/src/cpu/6502.c @@ -7,34 +7,23 @@ byte acc, X, Y, P, S = 0x00; address PC = 0x0000; byte* Memory; -byte getFlag(byte flag) { + +byte GetFlag(byte flag) { return (P & flag) ? 1 : 0; } + void SetFlag(byte flag, int x) { P = (P & ~flag) | ((x != 0) ? flag : 0); } -void flagSet(byte flag){ - P |= flag; -} - -void flagClear(byte flag){ - P &= ~flag; -} - -// Functions which perform reusable routines for finding if a specific flag should be set. -void SetFlagN(byte x){ - /*if ((x & flag_N) == flag_N) - SetFlag(flag_N, 1); - else - SetFlag(flag_N, 0);*/ +void SetFlag_N(byte x){ P = (x & flag_N) | (P & ~flag_N); } -//Perform prior to any changes TODO: FIX THIS! WTF WERE YOU THINKING? -void SetFlagV(byte x, byte y){ + +void SetFlag_V(byte x, byte y){ address z = (address)x + (address)y; if ((x & 0x80) != (y & 0x80)) SetFlag(flag_V, 1); @@ -42,44 +31,21 @@ void SetFlagV(byte x, byte y){ SetFlag(flag_V, 0); } -/*void SetFlagB(){ //WORK ON - SetFlag(flag_B, 1); -}*/ -/*void SetFlagD(){ - SetFlag(flag_D, 1); -}*/ - -/*void SetFlagI(){ //WORK ON - SetFlag(flag_Z, 1); -}*/ - -void SetFlagZ(int x){ +void SetFlag_Z(int x){ if (x == 0) SetFlag(flag_Z, 1); else SetFlag(flag_Z, 0); } -/*void SetFlagC(){ - SetFlag(flag_Z, 1); -}*/ - - -/*byte GetMemory(address x){ - return Memory[x]; -} - -void SetMemory(address x, byte y){ - Memory[x] = y; -}*/ - byte GetStack() { S--; return GetMemory(0x01FF - S); } + void SetStack(byte x) { SetMemory(0x01FF - S, x); S++; |