From 94d5ae52643affc829e80f020860278929006796 Mon Sep 17 00:00:00 2001
From: Eggbertx <eggbertx@users.noreply.github.com>
Date: Mon, 7 Oct 2024 11:08:32 -0700
Subject: [PATCH] Fix stack issues

---
 src/chip8.c | 8 +++-----
 src/chip8.h | 2 +-
 2 files changed, 4 insertions(+), 6 deletions(-)

diff --git a/src/chip8.c b/src/chip8.c
index 994361a..d059913 100755
--- 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
index b7fc8e0..fa626fd 100755
--- 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 */