Fix stack issues

Eggbertx · Oct 7, 2024 · 94d5ae5 · 94d5ae5
1 parent e306a27
commit 94d5ae5
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Showing 2 changed files with 4 additions and 6 deletions.
diff --git a/src/chip8.c b/src/chip8.c
@@ -142,7 +142,7 @@ void _OC8_FASTCALL doCycle() {
 	ushort nnn = 0;	/* -nnn */
 	uchar nn = 0;	/* --nn */
 	uchar n = 0;	/* ---n */
-	uchar event;
+
 	chip8.currentKey = -1; /* -1 if no keys are pressed, otherwise */
 
 	delay(1);
@@ -194,10 +194,9 @@ void _OC8_FASTCALL doCycle() {
 					CLEAR_CURENT_OPCODE();
 					strcpy(currentOpcode, "RET");
 				#endif
-				if(chip8.stackPointer)
-				chip8.PC = chip8.stack[chip8.stackPointer] + ROM_START_ADDR + 2;
 				if(chip8.stackPointer == 0)
 					goto stack_underflow;
+				chip8.PC = chip8.stack[chip8.stackPointer];
 				chip8.stackPointer--;
 			} else {
 				goto unrecognized_opcode;
@@ -223,11 +222,10 @@ void _OC8_FASTCALL doCycle() {
 				CLEAR_CURENT_OPCODE();
 				sprintf(currentOpcode, "CALL %#04x", nnn);
 			#endif
-			chip8.stack[chip8.stackPointer] = chip8.PC;
 			if(chip8.stackPointer >= 16)
 				goto stack_overflow;
-
 			chip8.stackPointer++;
+			chip8.stack[chip8.stackPointer] = chip8.PC;
 			chip8.PC = nnn;
 			break;
 		case 0x3000:

diff --git a/src/chip8.h b/src/chip8.h
@@ -60,7 +60,7 @@ struct Chip8 {
 						/* both timers down-count about 60 times per second when non-zero. */
 	uchar drawFlag;		/* if true, run draw function, this will likely be replaced later */
 
-	uchar stack[16];
+	ushort stack[16];
 	uchar stackPointer;
 	uchar memory[4096];	/* 4 KB, font located at 0x8110 */