From 3412a03a5ec20e1d3fb5dbd38888cf0c0eae09fc Mon Sep 17 00:00:00 2001
From: vin <git@vineetk.net>
Date: Mon, 10 Jun 2024 22:56:06 +0530
Subject: [PATCH] implement untested most of stack-related opcodes

---
 cpu.c | 127 +++++++++++++++++++++++++++-------------------------------
 1 file changed, 59 insertions(+), 68 deletions(-)

diff --git a/cpu.c b/cpu.c
index 5bd114e..e63760c 100644
--- a/cpu.c
+++ b/cpu.c
@@ -10,6 +10,11 @@
 #define STATUS_UPDATE_NEGATIVE(r)	\
 	(regs.status.negative = ((r & (1 << 7)) > 0))
 
+#define PUSH(b)	\
+	(memwrite(0x0100 + regs.sp--, b))
+#define PULL()	\
+	(peek(0x0100 + regs.sp++))
+
 struct cpu_flags {
 	uint8_t carry : 1;
 	uint8_t zero : 1;
@@ -467,51 +472,48 @@ ora(uint8_t arg)
 }
 
 static void
-pha(uint8_t arg)
+pha(void)
 {
-/* TODO: complete this */
+	PUSH(regs.a);
 }
 
 static void
-php(uint8_t arg)
+php(void)
 {
-/* TODO: complete this */
+	uint8_t status;
+
+	status = (regs.status.carry << 7) | (regs.status.zero << 6)
+	    | (regs.status.interrupt_disable << 5) | (regs.status.decimal_mode << 4)
+	    | (regs.status.brk << 3) | (regs.status.unused << 2)
+	    | (regs.status.overflow << 1) | regs.status.negative;
+
+	PUSH(status);
 }
 
 static void
-phx(uint8_t arg)
+pla(void)
 {
-/* TODO: complete this */
+	regs.a = PULL();
+
+	STATUS_UPDATE_ZERO(regs.a);
+	STATUS_UPDATE_NEGATIVE(regs.a);
 }
 
 static void
-phy(uint8_t arg)
+plp(void)
 {
-/* TODO: complete this */
-}
+	uint8_t status;
 
-static void
-pla(uint8_t arg)
-{
-/* TODO: complete this */
-}
+	status = PULL();
 
-static void
-plp(uint8_t arg)
-{
-/* TODO: complete this */
-}
-
-static void
-plx(uint8_t arg)
-{
-/* TODO: complete this */
-}
-
-static void
-ply(uint8_t arg)
-{
-/* TODO: complete this */
+	regs.status.carry = (status & (1 << 7)) > 0;
+	regs.status.zero = (status & (1 << 6)) > 0;
+	regs.status.interrupt_disable = (status & (1 << 5)) > 0;
+	regs.status.decimal_mode = (status & (1 << 4)) > 0;
+	regs.status.brk = (status & (1 << 3)) > 0;
+	regs.status.unused = (status & (1 << 2)) > 0;
+	regs.status.overflow = (status & (1 << 1)) > 0;
+	regs.status.negative = (status & 1) > 0;
 }
 
 static void
@@ -562,19 +564,19 @@ sbc(uint8_t arg)
 }
 
 static void
-sec(uint8_t arg)
+sec(void)
 {
 	regs.status.carry = 1;
 }
 
 static void
-sed(uint8_t arg)
+sed(void)
 {
 	regs.status.decimal_mode = 1;
 }
 
 static void
-sei(uint8_t arg)
+sei(void)
 {
 	regs.status.interrupt_disable = 1;
 }
@@ -607,7 +609,7 @@ tax(void)
 }
 
 static void
-tay(uint8_t arg)
+tay(void)
 {
 	regs.y = regs.a;
 
@@ -616,13 +618,16 @@ tay(uint8_t arg)
 }
 
 static void
-tsx(uint8_t arg)
+tsx(void)
 {
-/* TODO: complete this */
+	regs.x = PULL();
+
+	STATUS_UPDATE_ZERO(regs.x);
+	STATUS_UPDATE_NEGATIVE(regs.x);
 }
 
 static void
-txa(uint8_t arg)
+txa(void)
 {
 	regs.a = regs.x;
 
@@ -631,13 +636,13 @@ txa(uint8_t arg)
 }
 
 static void
-txs(uint8_t arg)
+txs(void)
 {
-/* TODO: complete this */
+	PUSH(regs.x);
 }
 
 static void
-tya(uint8_t arg)
+tya(void)
 {
 	regs.a = regs.y;
 
@@ -1121,35 +1126,19 @@ interpret(void)
 			cycles += 5;
 			break;
 		case 0x48:
-			pha(opcode_arg(AM_ACC));
+			pha();
 			cycles += 3;
 			break;
 		case 0x08:
-			php(opcode_arg(AM_ACC));
-			cycles += 3;
-			break;
-		case 0xda:
-			phx(opcode_arg(AM_ACC));
-			cycles += 3;
-			break;
-		case 0x5a:
-			phy(opcode_arg(AM_ACC));
+			php();
 			cycles += 3;
 			break;
 		case 0x68:
-			pla(opcode_arg(AM_ACC));
+			pla();
 			cycles += 4;
 			break;
 		case 0x28:
-			plp(opcode_arg(AM_ACC));
-			cycles += 4;
-			break;
-		case 0xfa:
-			plx(opcode_arg(AM_ACC));
-			cycles += 4;
-			break;
-		case 0x7a:
-			ply(opcode_arg(AM_ACC));
+			plp();
 			cycles += 4;
 			break;
 		case 0x2a:
@@ -1237,15 +1226,15 @@ interpret(void)
 			cycles += 5;
 			break;
 		case 0x38:
-			sec(opcode_arg(AM_ACC));
+			sec();
 			cycles += 2;
 			break;
 		case 0xf8:
-			sed(opcode_arg(AM_ACC));
+			sed();
 			cycles += 2;
 			break;
 		case 0x78:
-			sei(opcode_arg(AM_ACC));
+			sei();
 			cycles += 2;
 			break;
 		case 0x85:
@@ -1309,23 +1298,23 @@ interpret(void)
 			cycles += 2;
 			break;
 		case 0xa8:
-			tay(opcode_arg(AM_ACC));
+			tay();
 			cycles += 2;
 			break;
 		case 0xba:
-			tsx(opcode_arg(AM_ACC));
+			tsx();
 			cycles += 2;
 			break;
 		case 0x8a:
-			txa(opcode_arg(AM_ACC));
+			txa();
 			cycles += 2;
 			break;
 		case 0x9a:
-			txs(opcode_arg(AM_ACC));
+			txs();
 			cycles += 2;
 			break;
 		case 0x98:
-			tya(opcode_arg(AM_ACC));
+			tya();
 			cycles += 2;
 			break;
 		default:
@@ -1353,6 +1342,8 @@ cpu_init(void)
 
 	memset(&regs.status, 0, sizeof(regs.status));
 	regs.status.unused = 1;
+
+	cycles += 7;
 }
 
 int