diff options
| -rw-r--r-- | applesystem.h | 9 | ||||
| -rw-r--r-- | instruction.h | 161 |
2 files changed, 165 insertions, 5 deletions
diff --git a/applesystem.h b/applesystem.h index ea9b322..9b3dd1c 100644 --- a/applesystem.h +++ b/applesystem.h @@ -1,10 +1,13 @@ typedef unsigned char byte; -byte acc, X, Y, S, P = 0x00; +typedef unsigned short address; +byte acc, X, Y, P = 0x00; +unsigned short S = 0x0000; byte Memory[4096]; // TO DO. Add expansion capability to memory. /* To Do. + Find variables better passed as pointers instead + + Clean up this messy code */ @@ -32,10 +35,6 @@ void setFlag(byte flag, int x) { //OVERLOAD TO ACCEPT INT AS WELL } } -void toggleFlag(byte flag) { - P = ((P & flag) == flag) ? (P + flag) : (P - flag); -} - // BCD byte toBCD(byte x){ diff --git a/instruction.h b/instruction.h index 054e629..a5cc2b9 100644 --- a/instruction.h +++ b/instruction.h @@ -60,8 +60,41 @@ void fSBC(Addressing addr, int val){ //Increment and Decrement Instructions +void fINC(Addressing addr, int val){ + Memory[x]++; + setFlagD(Memory[x]); + setFlagZ(Memory[x]); +} + +void fINX(){ + X++; + setFlagD(X); + setFlagZ(X); +} + +void fINY(){ + Y++; + setFlagD(Y); + setFlagZ(Y); +} + +void fDEC(Addressing addr, int val){ + Memory[x]--; + setFlagD(Memory[x]); + setFlagZ(Memory[x]); +} +void fDEX(){ + X--; + setFlagD(X); + setFlagZ(X); +} +void fDEY(){ + Y--; + setFlagD(Y); + setFlagZ(Y); +} // Logical Instructions @@ -85,12 +118,94 @@ void fEOR(Addressing addr, int val){ // Jump, Branch, Compare, and Test Bits +void fJMP(int val){ + S = val; +} + +void fBCC(signed char val){ + if (getFlag(flag_C) == 0) S += val; +} + +void fBCS(signed char val){ + if (getFlag(flag_C) == 1) S += val; +} + +void fBEQ(signed char val){ + if (getFlag(flag_Z) == 1) S += val; +} + +void fBNE(signed char val){ + if (getFlag(flag_Z) == 0) S += val; +} + +void fBMI(signed char val){ + if (getFlag(flag_N) == 1) S += val; +} + +void fBPL(signed char val){ + if (getFlag(flag_N) == 0) S += val; +} + +void fBVS(signed char val){ + if (getFlag(flag_V) == 1) S += val; +} + +void fBVC(signed char val){ + if (getFlag(flag_V) == 0) S += val; +} + +void fCMP(address val){ + if (acc < Memory[val]){ + setFlag(flag_N, 1); setFlag(flag_Z, 0); setFlag(flag_C, 0); + }if (acc == Memory[val]){ + setFlag(flag_N, 0); setFlag(flag_Z, 1); setFlag(flag_C, 0); + }if (acc > Memory[val]){ + setFlag(flag_N, 0); setFlag(flag_Z, 0); setFlag(flag_C, 1); + } +} +void fCPX(address val){ + if (X < Memory[val]){ + setFlag(flag_N, 1); setFlag(flag_Z, 0); setFlag(flag_C, 0); + }if (X == Memory[val]){ + setFlag(flag_N, 0); setFlag(flag_Z, 1); setFlag(flag_C, 0); + }if (X > Memory[val]){ + setFlag(flag_N, 0); setFlag(flag_Z, 0); setFlag(flag_C, 1); + } +} +void fCPY(address val){ + if (Y < Memory[val]){ + setFlag(flag_N, 1); setFlag(flag_Z, 0); setFlag(flag_C, 0); + }if (Y == Memory[val]){ + setFlag(flag_N, 0); setFlag(flag_Z, 1); setFlag(flag_C, 0); + }if (Y > Memory[val]){ + setFlag(flag_N, 0); setFlag(flag_Z, 0); setFlag(flag_C, 1); + } +} +void fBIT(address val){ + setFlag(flag_N, (Memory[val] & flag_N)); + setFlag(flag_V, (Memory[val] & flag_V)); + if (((Memory[val] & flag_N) & (Memory[val] & flag_V)) == 0) { + setFlag(flag_Z, 1); + } else { + setFlag(flag_Z, 0); + } +} // Shift and Rotate Instructions +/* ASL - Accumulator Shift Left + LSR - Logical Shift Right + ROL - ROtate Left + ROR - ROtate Right + + Z is set if the result it zero. N is set if bit 7 is 1. It is + always reset on LSR. Remember that ASL A is equal to multiplying by + two and that LSR is equal to dividing by two.*/ + + void fASL(Addressing addr, int val){ setFlag(flag_C, (val & 0x80)); acc = (val << 1); @@ -98,9 +213,55 @@ void fASL(Addressing addr, int val){ setFlagZ(acc); } +/* Use these instructions to move things around in the accumulator or + memory. The net effects are (where C is the carry flag): + + + +-+-+-+-+-+-+-+-+ + C <- |7|6|5|4|3|2|1|0| <- 0 ASL + +-+-+-+-+-+-+-+-+ + + +-+-+-+-+-+-+-+-+ + 0 -> |7|6|5|4|3|2|1|0| -> C LSR + +-+-+-+-+-+-+-+-+ + + +-+-+-+-+-+-+-+-+ + C <- |7|6|5|4|3|2|1|0| <- C ROL + +-+-+-+-+-+-+-+-+ + + +-+-+-+-+-+-+-+-+ + C -> |7|6|5|4|3|2|1|0| -> C ROR + +-+-+-+-+-+-+-+-+ +*/ + // Transfer Instructions +void fTAX(){ + X = acc; + setFlagN(X); + setFlagZ(X); +} + +void fTAY(){ + Y = acc; + setFlagN(Y); + setFlagZ(Y); +} + +void fTXA(){ + acc = X; + setFlagN(acc); + setFlagZ(acc); +} + +void fTYA(){ + acc = Y; + setFlagN(acc); + setFlagZ(acc); +} + + // Stack Instructions // Subroutine Instructions |