sigonasr2/CHIP8Emulator
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Fix carry flags

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Co-authored-by: sigonasr2 <sigonasr2@gmail.com>
This commit is contained in:
sigonasr2 2023-01-08 16:54:26 -06:00
parent 27e6ab0d27
commit b9032c0d34
3 changed files with 69 additions and 26 deletions
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chip8-test-suite.ch8 Normal file
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95
main.cpp
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@ -9,7 +9,7 @@
using namespace olc;
bool USE_DEBUG_DISPLAY=true;
bool USE_DEBUG_DISPLAY=false;
int EMULATOR_SCREEN_WIDTH = 64;
int EMULATOR_SCREEN_HEIGHT = 32;
int EMULATOR_PIXEL_SIZE=5;
@ -66,6 +66,7 @@ public:
bool USE_ORIGINAL_CHIP8_SET=true; //True means use the original CHIP-8 spec (COSMAC VIP emulation). Set to false to use CHIP-48 spec.
bool PAUSED=true;
long instructionCount=0;
uint16_t watchMemoryAddress=0;
std::string Display8(int number){
std::bitset<8>numb(number);
@ -92,7 +93,7 @@ public:
for (int i=0;i<display.size();i++){
display[i]=0;
}
std::ifstream file("ChipWar.ch8",std::ios_base::binary);
std::ifstream file("chip8-test-suite.ch8",std::ios_base::binary);
uint16_t counter=0x200;
while (file.good()){
int val = file.get();
@ -116,6 +117,10 @@ public:
return true;
}
void OnTextEntryComplete(const std::string &sText) override{
watchMemoryAddress=std::stoul(sText.c_str(),nullptr,16);
}
bool OnUserUpdate(float fElapsedTime) override
{
if (!USE_DEBUG_DISPLAY||!PAUSED){
@ -130,23 +135,32 @@ public:
DrawDisplay();
}
} else {
if (GetKey(OEM_6).bPressed){
RunInstruction();
instructionCount++;
if (instructionCount%10==0){
advanceTimers(); //After 10 instructions, 1/60th of a second has passed.
if (GetKey(G).bPressed){
TextEntryEnable(true);
}
if (!IsTextEntryEnabled()){
if (GetKey(OEM_6).bPressed){
RunInstruction();
instructionCount++;
if (instructionCount%10==0){
advanceTimers(); //After 10 instructions, 1/60th of a second has passed.
}
DrawDisplay();
} else
if (GetKey(SPACE).bHeld){
RunInstruction();
instructionCount++;
if (instructionCount%10==0){
advanceTimers(); //After 10 instructions, 1/60th of a second has passed.
}
DrawDisplay();
}
DrawDisplay();
} else
if (GetKey(SPACE).bHeld){
RunInstruction();
instructionCount++;
if (instructionCount%10==0){
advanceTimers(); //After 10 instructions, 1/60th of a second has passed.
}
DrawDisplay();
}
}
if (IsTextEntryEnabled()){
DrawStringDecal({2,2},"Goto Memory Address: "+TextEntryGetString());
}
std::stringstream s;
s<<"PC: 0x"<<std::setfill('0')<< std::setw(4)<<std::hex<<pc;
std::string ss=s.str();
@ -205,6 +219,24 @@ public:
}
}
std::stringstream hexMemoryWatch;
hexMemoryWatch<<std::hex<<std::setfill('0')<<std::setw(4)<<watchMemoryAddress;
DrawStringDecal(vi2d{14+EMULATOR_PIXEL_SIZE*EMULATOR_SCREEN_WIDTH,18+21*10},"Memory Region [0x"+hexMemoryWatch.str()+"]:");
for (int j=0;j<12;j++){
std::stringstream memj;
memj<<std::hex<<std::setfill('0')<<std::setw(4)<<watchMemoryAddress+16*j;
DrawStringDecal(vi2d{14+EMULATOR_PIXEL_SIZE*EMULATOR_SCREEN_WIDTH,18+21*10+j*10+10},"0x"+memj.str());
for (int i=0;i<16;i++){
uint16_t mem = i+j*16+watchMemoryAddress;
if (mem<memory.size()){
std::stringstream hexval;
hexval<<std::hex<<std::setfill('0')<<std::setw(2)<<(int)memory[mem];
std::string sss=hexval.str();
std::transform(sss.begin(),sss.end(),sss.begin(),::toupper);
DrawStringDecal(vi2d{14+EMULATOR_PIXEL_SIZE*EMULATOR_SCREEN_WIDTH+8*8+i*3*8,18+21*10+j*10+10},sss);
}
}
}
return true;
}
@ -463,18 +495,21 @@ public:
reg[X]^=reg[Y];
}break;
case 0x4:{//Add VY to VX, set carry bit if overflow occurs.
reg[0xF]=0;
bool carryFlag=0;
if ((int)reg[X]+(int)reg[Y]>255){
reg[0xF]=1;
carryFlag=1;
}
reg[X]+=reg[Y];
reg[0xF]=carryFlag;
}break;
case 0x5:{// sets VX to the result of VX - VY.
reg[0xF]=0;
bool carryFlag=0;
if (reg[X]>reg[Y]){
reg[0xF]=1;
//reg[0xF]=1;
//carryFlag=1;
}
reg[X]-=reg[Y];
reg[0xF]=carryFlag;
}break;
case 0x6:{//Shift Right
if (USE_ORIGINAL_CHIP8_SET){
@ -485,15 +520,19 @@ public:
*/
reg[X]=reg[Y];
}
reg[0xF]=reg[X]&0x1;
bool carryFlag=reg[X]&0x1;
reg[X]>>=1;
reg[0xF]=carryFlag;
}break;
case 0x7:{//sets VX to the result of VY - VX. It's a reverse subtraction.
reg[0xF]=0;
//reg[0xF]=0;
bool carryFlag=false;
if (reg[Y]>reg[X]){
reg[0xF]=1;
//reg[0xF]=1;
carryFlag=true;
}
reg[X]=reg[Y]-reg[X];
reg[0xF]=carryFlag;
}break;
case 0xE:{//Shift Left
//std::cout<<"Y is: "<<(int)Y<<std::endl;
@ -505,8 +544,9 @@ public:
*/
reg[X]=reg[Y];
}
reg[0xF]=(reg[X]&0x80)>>7;
bool carryFlag=(reg[X]&0x80)>>7;
reg[X]<<=1;
reg[0xF]=carryFlag;
}break;
}
}break;
@ -571,11 +611,14 @@ public:
sound_timer=reg[X];
}break;
case 0x1E:{//The index register I will get the value in VX added to it.
reg[0xF]=0;
//reg[0xF]=0;
bool carryFlag=false;
if (index+reg[X]>=0x1000){
reg[0xF]=1;
//reg[0xF]=1;
carryFlag=true;
}
index+=reg[X];
reg[0xF]=carryFlag;
}break;
case 0x0A:{//This instruction “blocks”; it stops executing instructions and waits for key input
for (int i=0;i<keymap.size();i++){