From 8f09f4249cec8ccc187b3f9ee5094fb3080900a9 Mon Sep 17 00:00:00 2001 From: alekseiplusplus Date: Mon, 1 May 2023 11:00:25 +1000 Subject: memory access thru function; will be vital later. --- headers/6502.h | 16 +++++++++++++--- headers/addressing.h | 14 +++++++------- headers/apple.h | 4 +++- headers/debug.h | 1 + headers/instructions/definitions.h | 32 +++++++++++++++++++------------- 5 files changed, 43 insertions(+), 24 deletions(-) (limited to 'headers') diff --git a/headers/6502.h b/headers/6502.h index 0835f36..3a48edc 100644 --- a/headers/6502.h +++ b/headers/6502.h @@ -1,8 +1,11 @@ // 6502.h // Core elements of the 6502 CPU -typedef unsigned char byte; -typedef unsigned short address; +typedef unsigned char\ + byte; +typedef unsigned short\ + address; + byte acc, X, Y, P, S = 0x00; address PC = 0x0000; byte* Memory; // TO DO. Add expansion capability to memory. @@ -106,8 +109,15 @@ void setFlagZ(int x){ }*/ +// Memory Manipulation +//need to add special conditions for D0 and FF +byte getMemory(address x){ + return Memory[x]; +} - +void setMemory(address x, byte y){ + Memory[x] = y; +} diff --git a/headers/addressing.h b/headers/addressing.h index af102fd..c5db440 100644 --- a/headers/addressing.h +++ b/headers/addressing.h @@ -37,7 +37,7 @@ int fAddressGetLength(Addressing addr){ switch(addr){ case eAbsolute: case eAbsoluteIndexedX: case eAbsoluteIndexedY: return 3; - case eAccumulator: + case eAccumulator: case eImplied: return 1; default: return 2; @@ -93,10 +93,10 @@ AddData fAddress(Addressing addr, short x) { break; case eIndexedIndirect: - ret.add = (((address)Memory[x+X+1])<<8) + (Memory[x+X]); + ret.add = ((getMemory(x+X+1))<<8) + (getMemory(x+X)); break; case eIndirectIndexed: - ret.add = (((address)Memory[x+1])<<8) + (Memory[x]) + Y; + ret.add = ((getMemory(x+1))<<8) + (getMemory(x)) + Y; break; } @@ -117,7 +117,7 @@ AddData fAddress(Addressing addr, short x) { break; default: - ret.value = Memory[ret.add]; + ret.value = getMemory(ret.add); } // LENGTH @@ -214,11 +214,11 @@ AddData fAddress(Addressing addr, short x) { || current_instruction == &fEOR || current_instruction == &fAND || current_instruction == &fORA || current_instruction == &fCMP ){ switch(addr){ case eAbsoluteIndexedX: - if ((x & 0xFFFC) != ((x + X) & 0xFFFC)) ret.cycles++; break; + if ((x & 0xFF00) != ((x + X) & 0xFF00)) ret.cycles++; break; case eAbsoluteIndexedY: - if ((x & 0xFFFC) != ((x + Y) & 0xFFFC)) ret.cycles++; break; + if ((x & 0xFF00) != ((x + Y) & 0xFF00)) ret.cycles++; break; case eIndirectIndexed: - if ((ret.add & 0xFFFC) != (ret.add - Y & 0xFFFC)) ret.cycles++; break; + if ((ret.add & 0xFF00) != (ret.add - Y & 0xFF00)) ret.cycles++; break; } } diff --git a/headers/apple.h b/headers/apple.h index b17124b..55ddaa3 100644 --- a/headers/apple.h +++ b/headers/apple.h @@ -10,4 +10,6 @@ void AppleReset(){ idata.cycles = 0; idata.length = 0; idata.add = 0; idata.value = 0; free(Memory); Memory = calloc(MEMORY_SIZE, sizeof(byte)); -} \ No newline at end of file +} + + diff --git a/headers/debug.h b/headers/debug.h index cb9cc85..06d4733 100644 --- a/headers/debug.h +++ b/headers/debug.h @@ -39,5 +39,6 @@ printf("\ \t....Y:\t%x\t...add:\t%x\n\ \tstack:\t%x\t.value:\t%x\n\ \tflags:\t%x\n\ +\n\ ", acc, idata.cycles, X, idata.length, Y, idata.add, S, idata.value, P); } diff --git a/headers/instructions/definitions.h b/headers/instructions/definitions.h index bdeb54e..937ca10 100644 --- a/headers/instructions/definitions.h +++ b/headers/instructions/definitions.h @@ -27,15 +27,15 @@ void fLDY(Addressing addr, address val){ idata = fAddress(addr, val); } void fSTA(Addressing addr, address val){ idata = fAddress(addr, val); - Memory[idata.add] = acc; + setMemory(idata.add, acc); } void fSTX(Addressing addr, address val){ idata = fAddress(addr, val); - Memory[idata.add] = X; + setMemory(idata.add, X); } void fSTY(Addressing addr, address val){ idata = fAddress(addr, val); - Memory[idata.add] = Y; + setMemory(idata.add, Y); } // Arithmetic Instructions @@ -71,7 +71,9 @@ void fSBC(Addressing addr, address val){ idata = fAddress(addr, val); //Increment and Decrement Instructions void fINC(Addressing addr, address val){ idata = fAddress(addr, val); - Memory[idata.add]++; + byte a = getMemory(idata.add); + a++; + setMemory(idata.add, a); setFlagN(Memory[idata.add]); setFlagZ(Memory[idata.add]); } @@ -89,7 +91,9 @@ void fINY(Addressing addr, address val){ idata = fAddress(addr, val); } void fDEC(Addressing addr, address val){ idata = fAddress(addr, val); - Memory[idata.add]--; + byte a = getMemory(idata.add); + a--; + setMemory(idata.add, a); setFlagN(Memory[idata.add]); setFlagZ(Memory[idata.add]); } @@ -195,11 +199,12 @@ void fCPY(Addressing addr, address val){ idata = fAddress(addr, val); } } -//Need to double check the function of this instruction +//NEED TO DOUBLE CHECK THIS INSTRUCTION void fBIT(Addressing addr, address val){ idata = fAddress(addr, 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_N, (idata.value & flag_N)); + setFlag(flag_V, (idata.value & flag_V)); + + if (((idata.value & flag_N) & (idata.value & flag_V)) == 0) { flagSet(flag_Z); } else { flagSet(flag_Z); @@ -275,26 +280,27 @@ void fTXS(Addressing addr, address val){ idata = fAddress(addr, val); } void fPHA(Addressing addr, address val){ idata = fAddress(addr, val); - Memory[0x01FF-S] = acc; + setMemory(0x01FF-S, acc); S++; } void fPHP(Addressing addr, address val){ idata = fAddress(addr, val); - Memory[0x01FF-S] = P; + setMemory(0x01FF-S, P); S++; } void fPLA(Addressing addr, address val){ idata = fAddress(addr, val); S--; - acc = Memory[0x01FF-S]; + acc = getMemory(0x01FF-S); } void fPLP(Addressing addr, address val){ idata = fAddress(addr, val); S--; - P = Memory[0x01FF-S]; + P = getMemory(0x01FF-S); } // Subroutine Instructions +// NEED TO FINISH THESE void fJSR(Addressing addr, address val){ idata = fAddress(addr, val); Memory[0x01FF-S] = (idata.add-1); -- cgit v1.2.3