ash/chip-8_emulator
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Fix bug with FX0A

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This commit is contained in:
Alex
2018-10-29 18:25:06 -04:00
parent 8795f83f75
commit 6bd3a22e5b
1 changed files with 9 additions and 7 deletions
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16
main.c
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@@ -53,6 +53,7 @@ int main(int argc, char **argv) {
int frame = 0; int frame = 0;
int press = 0; int press = 0;
int wait = 0; int wait = 0;
int store = 0;
while (1) { while (1) {
if (DEBUG) printf("0x%x ", state.program_counter); if (DEBUG) printf("0x%x ", state.program_counter);
@@ -66,10 +67,7 @@ int main(int argc, char **argv) {
press = 0; press = 0;
} }
clock_t start = clock() / (CLOCKS_PER_SEC/1000);
// opcodes are 16 bits // opcodes are 16 bits
word opcode = (state.memory[state.program_counter++] << 8) | (state.memory[state.program_counter++]);
SDL_PollEvent(&e); SDL_PollEvent(&e);
if (e.type == SDL_QUIT) break; if (e.type == SDL_QUIT) break;
@@ -91,13 +89,15 @@ int main(int argc, char **argv) {
for (int i = 0; i < 0x10; ++i) { for (int i = 0; i < 0x10; ++i) {
if (state.input[i] != 0) if (state.input[i] != 0)
{ {
state.registers[0xF] = i; state.registers[store] = i;
break; break;
} }
} }
wait = 0; wait = 0;
} }
word opcode = (state.memory[state.program_counter++] << 8) | (state.memory[state.program_counter++]);
switch (opcode & 0xF000) switch (opcode & 0xF000)
{ {
case 0x0000: // screen clear or function return case 0x0000: // screen clear or function return
@@ -284,9 +284,11 @@ int main(int argc, char **argv) {
byte data = state.memory[state.address_I + line]; byte data = state.memory[state.address_I + line];
for (int xpos = 0; xpos < 8; ++xpos) for (int xpos = 0; xpos < 8; ++xpos)
{ {
int ypos = y + line;
if (ypos > 63) ypos -= 64;
if (!(data & (1 << xpos))) continue; if (!(data & (1 << xpos))) continue;
if (state.screen[x + (7 - xpos)][y + line]) state.registers[0xF] = 1; if (state.screen[x + (7 - xpos)][ypos]) state.registers[0xF] = 1;
state.screen[x + (7 - xpos)][y + line] ^= 1; state.screen[x + (7 - xpos)][ypos] ^= 1;
} }
} }
@@ -329,6 +331,7 @@ int main(int argc, char **argv) {
case 0x0A: case 0x0A:
wait = 1; wait = 1;
store = reg;
break; break;
case 0x15: case 0x15:
@@ -393,7 +396,6 @@ int main(int argc, char **argv) {
SDL_RenderPresent(renderer); SDL_RenderPresent(renderer);
clock_t stop = clock() / (CLOCKS_PER_SEC/1000);
SDL_Delay(1); SDL_Delay(1);
++frame; ++frame;
// SDL_DestroyWindow(window); // SDL_DestroyWindow(window);