From 2f2d9cf8eeb0ea61a89c49dd56d53ede0478265b Mon Sep 17 00:00:00 2001
From: Toni <antpiasecki@gmail.com>
Date: Sun, 13 Jul 2025 20:16:55 +0200
Subject: [PATCH] replace READ_ADDR

---
 mos6502.c | 307 +++++++++++++++++++++++-------------------------------
 1 file changed, 128 insertions(+), 179 deletions(-)

diff --git a/mos6502.c b/mos6502.c
index 900a762..e7d5ad1 100644
--- a/mos6502.c
+++ b/mos6502.c
@@ -4,10 +4,8 @@
 #include <stdio.h>
 #include <stdlib.h>
 
-#define READ_ADDR()                                                            \
-  uint16_t low = m->memory[m->pc++];                                           \
-  uint16_t high = m->memory[m->pc++];                                          \
-  uint16_t addr = (high << 8) | low
+#define READ_U8() m->memory[m->pc++]
+#define READ_U16() (READ_U8() | (READ_U8() << 8))
 
 typedef struct MOS6502 {
   uint8_t *memory;
@@ -31,263 +29,239 @@ void mos6502_disassemble(MOS6502 *m, size_t program_size) {
   while (m->pc < 0x600 + program_size) {
     printf("%04X: ", m->pc);
 
-    uint8_t op = m->memory[m->pc++];
+    uint8_t op = READ_U8();
     switch (op) {
     case 0x00: {
       printf("BRK\n");
     } break;
     case 0x01: {
-      printf("ORA ($%02X,X)\n", m->memory[m->pc++]);
+      printf("ORA ($%02X,X)\n", READ_U8());
     } break;
     case 0x05: {
-      printf("ORA $%02X\n", m->memory[m->pc++]);
+      printf("ORA $%02X\n", READ_U8());
     } break;
     case 0x06: {
-      printf("ASL $%02X\n", m->memory[m->pc++]);
+      printf("ASL $%02X\n", READ_U8());
     } break;
     case 0x08: {
       printf("PHP\n");
     } break;
     case 0x09: {
-      printf("ORA #$%02X\n", m->memory[m->pc++]);
+      printf("ORA #$%02X\n", READ_U8());
     } break;
     case 0x0A: {
       printf("ASL A\n");
     } break;
     case 0x0D: {
-      READ_ADDR();
-      printf("ORA $%04X\n", addr);
+      printf("ORA $%04X\n", READ_U16());
     } break;
     case 0x0E: {
-      READ_ADDR();
-      printf("ASL $%04X\n", addr);
+      printf("ASL $%04X\n", READ_U16());
     } break;
     case 0x10: {
-      int8_t offset = m->memory[m->pc++];
+      int8_t offset = READ_U8();
       printf("BPL $%04X\n", m->pc + offset);
     } break;
     case 0x11: {
-      printf("ORA ($%02X),Y\n", m->memory[m->pc++]);
+      printf("ORA ($%02X),Y\n", READ_U8());
     } break;
     case 0x15: {
-      printf("ORA $%02X,X\n", m->memory[m->pc++]);
+      printf("ORA $%02X,X\n", READ_U8());
     } break;
     case 0x16: {
-      printf("ASL $%02X,X\n", m->memory[m->pc++]);
+      printf("ASL $%02X,X\n", READ_U8());
     } break;
     case 0x18: {
       printf("CLC\n");
     } break;
     case 0x19: {
-      READ_ADDR();
-      printf("ORA $%04X,Y\n", addr);
+      printf("ORA $%04X,Y\n", READ_U16());
     } break;
     case 0x1D: {
-      READ_ADDR();
-      printf("ORA $%04X,X\n", addr);
+      printf("ORA $%04X,X\n", READ_U16());
     } break;
     case 0x1E: {
-      READ_ADDR();
-      printf("ASL $%04X,X\n", addr);
+      printf("ASL $%04X,X\n", READ_U16());
     } break;
     case 0x20: {
-      READ_ADDR();
-      printf("JSR $%04X\n", addr);
+      printf("JSR $%04X\n", READ_U16());
     } break;
     case 0x21: {
-      printf("AND ($%02X,X)\n", m->memory[m->pc++]);
+      printf("AND ($%02X,X)\n", READ_U8());
     } break;
     case 0x24: {
-      printf("BIT $%02X\n", m->memory[m->pc++]);
+      printf("BIT $%02X\n", READ_U8());
     } break;
     case 0x25: {
-      printf("AND $%02X\n", m->memory[m->pc++]);
+      printf("AND $%02X\n", READ_U8());
     } break;
     case 0x26: {
-      printf("ROL $%02X\n", m->memory[m->pc++]);
+      printf("ROL $%02X\n", READ_U8());
     } break;
     case 0x28: {
       printf("PLP\n");
     } break;
     case 0x29: {
-      printf("AND #$%02X\n", m->memory[m->pc++]);
+      printf("AND #$%02X\n", READ_U8());
     } break;
     case 0x2A: {
       printf("ROL A\n");
     } break;
     case 0x2C: {
-      READ_ADDR();
-      printf("BIT $%04X\n", addr);
+      printf("BIT $%04X\n", READ_U16());
     } break;
     case 0x2D: {
-      READ_ADDR();
-      printf("AND $%04X\n", addr);
+      printf("AND $%04X\n", READ_U16());
     } break;
     case 0x2E: {
-      READ_ADDR();
-      printf("ROL $%04X\n", addr);
+      printf("ROL $%04X\n", READ_U16());
     } break;
     case 0x30: {
-      int8_t offset = m->memory[m->pc++];
+      int8_t offset = READ_U8();
       printf("BMI $%04X\n", m->pc + offset);
     } break;
     case 0x31: {
-      printf("AND ($%02X),Y\n", m->memory[m->pc++]);
+      printf("AND ($%02X),Y\n", READ_U8());
     } break;
     case 0x35: {
-      printf("AND $%02X,X\n", m->memory[m->pc++]);
+      printf("AND $%02X,X\n", READ_U8());
     } break;
     case 0x36: {
-      printf("ROL $%02X,X\n", m->memory[m->pc++]);
+      printf("ROL $%02X,X\n", READ_U8());
     } break;
     case 0x38: {
       printf("SEC\n");
     } break;
     case 0x39: {
-      READ_ADDR();
-      printf("AND $%04X,Y\n", addr);
+      printf("AND $%04X,Y\n", READ_U16());
     } break;
     case 0x3D: {
-      READ_ADDR();
-      printf("AND $%04X,X\n", addr);
+      printf("AND $%04X,X\n", READ_U16());
     } break;
     case 0x3E: {
-      READ_ADDR();
-      printf("ROL $%04X,X\n", addr);
+      printf("ROL $%04X,X\n", READ_U16());
     } break;
     case 0x40: {
       printf("RTI\n");
     } break;
     case 0x41: {
-      printf("EOR ($%02X,X)\n", m->memory[m->pc++]);
+      printf("EOR ($%02X,X)\n", READ_U8());
     } break;
     case 0x45: {
-      printf("EOR $%02X\n", m->memory[m->pc++]);
+      printf("EOR $%02X\n", READ_U8());
     } break;
     case 0x46: {
-      printf("LSR $%02X\n", m->memory[m->pc++]);
+      printf("LSR $%02X\n", READ_U8());
     } break;
     case 0x48: {
       printf("PHA\n");
     } break;
     case 0x49: {
-      printf("EOR #$%02X\n", m->memory[m->pc++]);
+      printf("EOR #$%02X\n", READ_U8());
     } break;
     case 0x4A: {
       printf("LSR A\n");
     } break;
     case 0x4C: {
-      READ_ADDR();
-      printf("JMP $%04X\n", addr);
+      printf("JMP $%04X\n", READ_U16());
     } break;
     case 0x4D: {
-      READ_ADDR();
-      printf("EOR $%04X\n", addr);
+      printf("EOR $%04X\n", READ_U16());
     } break;
     case 0x4E: {
-      READ_ADDR();
-      printf("LSR $%04X\n", addr);
+      printf("LSR $%04X\n", READ_U16());
     } break;
     case 0x50: {
-      int8_t offset = m->memory[m->pc++];
+      int8_t offset = READ_U8();
       printf("BVC $%04X\n", m->pc + offset);
     } break;
     case 0x51: {
-      printf("EOR ($%02X),Y\n", m->memory[m->pc++]);
+      printf("EOR ($%02X),Y\n", READ_U8());
     } break;
     case 0x55: {
-      printf("EOR $%02X,X\n", m->memory[m->pc++]);
+      printf("EOR $%02X,X\n", READ_U8());
     } break;
     case 0x56: {
-      printf("LSR $%02X,X\n", m->memory[m->pc++]);
+      printf("LSR $%02X,X\n", READ_U8());
     } break;
     case 0x58: {
       printf("CLI\n");
     } break;
     case 0x59: {
-      READ_ADDR();
-      printf("EOR $%04X,Y\n", addr);
+      printf("EOR $%04X,Y\n", READ_U16());
     } break;
     case 0x5D: {
-      READ_ADDR();
-      printf("EOR $%04X,X\n", addr);
+      printf("EOR $%04X,X\n", READ_U16());
     } break;
     case 0x5E: {
-      READ_ADDR();
-      printf("LSR $%04X,X\n", addr);
+      printf("LSR $%04X,X\n", READ_U16());
     } break;
     case 0x60: {
       printf("RTS\n");
     } break;
     case 0x61: {
-      printf("ADC ($%02X,X)\n", m->memory[m->pc++]);
+      printf("ADC ($%02X,X)\n", READ_U8());
     } break;
     case 0x65: {
-      printf("ADC $%02X\n", m->memory[m->pc++]);
+      printf("ADC $%02X\n", READ_U8());
     } break;
     case 0x66: {
-      printf("ROR $%02X\n", m->memory[m->pc++]);
+      printf("ROR $%02X\n", READ_U8());
     } break;
     case 0x68: {
       printf("PLA\n");
     } break;
     case 0x69: {
-      printf("ADC #$%02X\n", m->memory[m->pc++]);
+      printf("ADC #$%02X\n", READ_U8());
     } break;
     case 0x6A: {
       printf("ROR A\n");
     } break;
     case 0x6C: {
-      READ_ADDR();
-      printf("JMP ($%04X)\n", addr);
+      printf("JMP ($%04X)\n", READ_U16());
     } break;
     case 0x6D: {
-      READ_ADDR();
-      printf("ADC $%04X\n", addr);
+      printf("ADC $%04X\n", READ_U16());
     } break;
     case 0x6E: {
-      READ_ADDR();
-      printf("ROR $%04X\n", addr);
+      printf("ROR $%04X\n", READ_U16());
     } break;
     case 0x70: {
-      int8_t offset = m->memory[m->pc++];
+      int8_t offset = READ_U8();
       printf("BVS $%04X\n", m->pc + offset);
     } break;
     case 0x71: {
-      printf("ADC ($%02X),Y\n", m->memory[m->pc++]);
+      printf("ADC ($%02X),Y\n", READ_U8());
     } break;
     case 0x75: {
-      printf("ADC $%02X,X\n", m->memory[m->pc++]);
+      printf("ADC $%02X,X\n", READ_U8());
     } break;
     case 0x76: {
-      printf("ROR $%02X,X\n", m->memory[m->pc++]);
+      printf("ROR $%02X,X\n", READ_U8());
     } break;
     case 0x78: {
       printf("SEI\n");
     } break;
     case 0x79: {
-      READ_ADDR();
-      printf("ADC $%04X,Y\n", addr);
-    } break;
-    case 0x7E: {
-      READ_ADDR();
-      printf("ROR $%04X,X\n", addr);
+      printf("ADC $%04X,Y\n", READ_U16());
     } break;
     case 0x7D: {
-      READ_ADDR();
-      printf("ADC $%04X,X\n", addr);
+      printf("ADC $%04X,X\n", READ_U16());
+    } break;
+    case 0x7E: {
+      printf("ROR $%04X,X\n", READ_U16());
     } break;
     case 0x81: {
-      printf("STA ($%02X,X)\n", m->memory[m->pc++]);
+      printf("STA ($%02X,X)\n", READ_U8());
     } break;
     case 0x84: {
-      printf("STY $%02X\n", m->memory[m->pc++]);
+      printf("STY $%02X\n", READ_U8());
     } break;
     case 0x85: {
-      printf("STA $%02X\n", m->memory[m->pc++]);
+      printf("STA $%02X\n", READ_U8());
     } break;
     case 0x86: {
-      printf("STX $%02X\n", m->memory[m->pc++]);
+      printf("STX $%02X\n", READ_U8());
     } break;
     case 0x88: {
       printf("DEY\n");
@@ -296,255 +270,230 @@ void mos6502_disassemble(MOS6502 *m, size_t program_size) {
       printf("TXA\n");
     } break;
     case 0x8C: {
-      READ_ADDR();
-      printf("STY $%04X\n", addr);
+      printf("STY $%04X\n", READ_U16());
     } break;
     case 0x8D: {
-      READ_ADDR();
-      printf("STA $%04X\n", addr);
+      printf("STA $%04X\n", READ_U16());
     } break;
     case 0x8E: {
-      READ_ADDR();
-      printf("STX $%04X\n", addr);
+      printf("STX $%04X\n", READ_U16());
     } break;
     case 0x90: {
-      int8_t offset = m->memory[m->pc++];
+      int8_t offset = READ_U8();
       printf("BCC $%04X\n", m->pc + offset);
     } break;
     case 0x91: {
-      printf("STA ($%02X),Y\n", m->memory[m->pc++]);
+      printf("STA ($%02X),Y\n", READ_U8());
     } break;
     case 0x94: {
-      printf("STY $%02X,X\n", m->memory[m->pc++]);
+      printf("STY $%02X,X\n", READ_U8());
     } break;
     case 0x95: {
-      printf("STA $%02X,X\n", m->memory[m->pc++]);
+      printf("STA $%02X,X\n", READ_U8());
     } break;
     case 0x96: {
-      printf("STX $%02X,Y\n", m->memory[m->pc++]);
+      printf("STX $%02X,Y\n", READ_U8());
     } break;
     case 0x98: {
       printf("TYA\n");
     } break;
     case 0x99: {
-      READ_ADDR();
-      printf("STA $%04X,Y\n", addr);
+      printf("STA $%04X,Y\n", READ_U16());
     } break;
     case 0x9A: {
       printf("TXS\n");
     } break;
     case 0x9D: {
-      READ_ADDR();
-      printf("STA $%04X,X\n", addr);
+      printf("STA $%04X,X\n", READ_U16());
     } break;
     case 0xA0: {
-      printf("LDY #$%02X\n", m->memory[m->pc++]);
+      printf("LDY #$%02X\n", READ_U8());
     } break;
     case 0xA1: {
-      printf("LDA ($%02X,X)\n", m->memory[m->pc++]);
+      printf("LDA ($%02X,X)\n", READ_U8());
     } break;
     case 0xA2: {
-      printf("LDX #$%02X\n", m->memory[m->pc++]);
+      printf("LDX #$%02X\n", READ_U8());
     } break;
     case 0xA4: {
-      printf("LDY $%02X\n", m->memory[m->pc++]);
+      printf("LDY $%02X\n", READ_U8());
     } break;
     case 0xA5: {
-      printf("LDA $%02X\n", m->memory[m->pc++]);
+      printf("LDA $%02X\n", READ_U8());
     } break;
     case 0xA6: {
-      printf("LDX $%02X\n", m->memory[m->pc++]);
+      printf("LDX $%02X\n", READ_U8());
     } break;
     case 0xA8: {
       printf("TAY\n");
     } break;
     case 0xA9: {
-      printf("LDA #$%02X\n", m->memory[m->pc++]);
+      printf("LDA #$%02X\n", READ_U8());
     } break;
     case 0xAA: {
       printf("TAX\n");
     } break;
     case 0xAC: {
-      READ_ADDR();
-      printf("LDY $%04X\n", addr);
+      printf("LDY $%04X\n", READ_U16());
     } break;
     case 0xAD: {
-      READ_ADDR();
-      printf("LDA $%04X\n", addr);
+      printf("LDA $%04X\n", READ_U16());
     } break;
     case 0xAE: {
-      READ_ADDR();
-      printf("LDX $%04X\n", addr);
+      printf("LDX $%04X\n", READ_U16());
     } break;
     case 0xB0: {
-      int8_t offset = m->memory[m->pc++];
+      int8_t offset = READ_U8();
       printf("BCS $%04X\n", m->pc + offset);
     } break;
     case 0xB1: {
-      printf("LDA ($%02X,Y)\n", m->memory[m->pc++]);
+      printf("LDA ($%02X),Y\n", READ_U8());
     } break;
     case 0xB4: {
-      printf("LDY $%02X,X\n", m->memory[m->pc++]);
+      printf("LDY $%02X,X\n", READ_U8());
     } break;
     case 0xB5: {
-      printf("LDA $%02X,X\n", m->memory[m->pc++]);
+      printf("LDA $%02X,X\n", READ_U8());
     } break;
     case 0xB6: {
-      printf("LDX $%02X,Y\n", m->memory[m->pc++]);
+      printf("LDX $%02X,Y\n", READ_U8());
     } break;
     case 0xB8: {
       printf("CLV\n");
     } break;
     case 0xB9: {
-      READ_ADDR();
-      printf("LDA $%04X,Y\n", addr);
+      printf("LDA $%04X,Y\n", READ_U16());
     } break;
     case 0xBA: {
       printf("TSX\n");
     } break;
     case 0xBC: {
-      READ_ADDR();
-      printf("LDY $%04X,X\n", addr);
+      printf("LDY $%04X,X\n", READ_U16());
     } break;
     case 0xBD: {
-      READ_ADDR();
-      printf("LDA $%04X,X\n", addr);
+      printf("LDA $%04X,X\n", READ_U16());
     } break;
     case 0xBE: {
-      READ_ADDR();
-      printf("LDX $%04X,Y\n", addr);
+      printf("LDX $%04X,Y\n", READ_U16());
     } break;
     case 0xC0: {
-      printf("CPY #$%02X\n", m->memory[m->pc++]);
+      printf("CPY #$%02X\n", READ_U8());
     } break;
     case 0xC1: {
-      printf("CMP ($%02X,X)\n", m->memory[m->pc++]);
+      printf("CMP ($%02X,X)\n", READ_U8());
     } break;
     case 0xC4: {
-      printf("CPY $%02X\n", m->memory[m->pc++]);
+      printf("CPY $%02X\n", READ_U8());
     } break;
     case 0xC5: {
-      printf("CMP $%02X\n", m->memory[m->pc++]);
+      printf("CMP $%02X\n", READ_U8());
     } break;
     case 0xC6: {
-      printf("DEC $%02X\n", m->memory[m->pc++]);
+      printf("DEC $%02X\n", READ_U8());
     } break;
     case 0xC8: {
       printf("INY\n");
     } break;
     case 0xC9: {
-      printf("CMP #$%02X\n", m->memory[m->pc++]);
+      printf("CMP #$%02X\n", READ_U8());
     } break;
     case 0xCA: {
       printf("DEX\n");
     } break;
     case 0xCC: {
-      READ_ADDR();
-      printf("CPY $%04X\n", addr);
+      printf("CPY $%04X\n", READ_U16());
     } break;
     case 0xCD: {
-      READ_ADDR();
-      printf("CMP $%04X\n", addr);
+      printf("CMP $%04X\n", READ_U16());
     } break;
     case 0xCE: {
-      READ_ADDR();
-      printf("DEC $%04X\n", addr);
+      printf("DEC $%04X\n", READ_U16());
     } break;
     case 0xD0: {
-      int8_t offset = m->memory[m->pc++];
+      int8_t offset = READ_U8();
       printf("BNE $%04X\n", m->pc + offset);
     } break;
     case 0xD1: {
-      printf("CMP ($%02X),Y\n", m->memory[m->pc++]);
+      printf("CMP ($%02X),Y\n", READ_U8());
     } break;
     case 0xD5: {
-      printf("CMP $%02X,X\n", m->memory[m->pc++]);
+      printf("CMP $%02X,X\n", READ_U8());
     } break;
     case 0xD6: {
-      printf("DEC $%02X,X\n", m->memory[m->pc++]);
+      printf("DEC $%02X,X\n", READ_U8());
     } break;
     case 0xD8: {
       printf("CLD\n");
     } break;
     case 0xD9: {
-      READ_ADDR();
-      printf("CMP $%04X,Y\n", addr);
+      printf("CMP $%04X,Y\n", READ_U16());
     } break;
     case 0xDD: {
-      READ_ADDR();
-      printf("CMP $%04X,X\n", addr);
+      printf("CMP $%04X,X\n", READ_U16());
     } break;
     case 0xDE: {
-      READ_ADDR();
-      printf("DEC $%04X,X\n", addr);
+      printf("DEC $%04X,X\n", READ_U16());
     } break;
     case 0xE0: {
-      printf("CPX #$%02X\n", m->memory[m->pc++]);
+      printf("CPX #$%02X\n", READ_U8());
     } break;
     case 0xE1: {
-      printf("SBC ($%02X,X)\n", m->memory[m->pc++]);
+      printf("SBC ($%02X,X)\n", READ_U8());
     } break;
     case 0xE4: {
-      printf("CPX $%02X\n", m->memory[m->pc++]);
+      printf("CPX $%02X\n", READ_U8());
     } break;
     case 0xE5: {
-      printf("SBC $%02X\n", m->memory[m->pc++]);
+      printf("SBC $%02X\n", READ_U8());
     } break;
     case 0xE6: {
-      printf("INC $%02X\n", m->memory[m->pc++]);
+      printf("INC $%02X\n", READ_U8());
     } break;
     case 0xE8: {
       printf("INX\n");
     } break;
     case 0xE9: {
-      printf("SBC #$%02X\n", m->memory[m->pc++]);
+      printf("SBC #$%02X\n", READ_U8());
     } break;
     case 0xEA: {
       printf("NOP\n");
     } break;
     case 0xEC: {
-      READ_ADDR();
-      printf("CPX $%04X\n", addr);
+      printf("CPX $%04X\n", READ_U16());
     } break;
     case 0xED: {
-      READ_ADDR();
-      printf("SBC $%04X\n", addr);
+      printf("SBC $%04X\n", READ_U16());
     } break;
     case 0xEE: {
-      READ_ADDR();
-      printf("INC $%04X\n", addr);
+      printf("INC $%04X\n", READ_U16());
     } break;
     case 0xF0: {
-      int8_t offset = m->memory[m->pc++];
+      int8_t offset = READ_U8();
       printf("BEQ $%04X\n", m->pc + offset);
     } break;
     case 0xF1: {
-      printf("SBC ($%02X),Y\n", m->memory[m->pc++]);
+      printf("SBC ($%02X),Y\n", READ_U8());
     } break;
     case 0xF5: {
-      printf("SBC $%02X,X\n", m->memory[m->pc++]);
+      printf("SBC $%02X,X\n", READ_U8());
     } break;
     case 0xF6: {
-      printf("INC $%02X,X\n", m->memory[m->pc++]);
+      printf("INC $%02X,X\n", READ_U8());
     } break;
     case 0xF8: {
       printf("SED\n");
     } break;
     case 0xF9: {
-      READ_ADDR();
-      printf("SBC $%04X,Y\n", addr);
+      printf("SBC $%04X,Y\n", READ_U16());
     } break;
     case 0xFD: {
-      READ_ADDR();
-      printf("SBC $%04X,X\n", addr);
+      printf("SBC $%04X,X\n", READ_U16());
     } break;
     case 0xFE: {
-      READ_ADDR();
-      printf("INC $%04X,X\n", addr);
+      printf("INC $%04X,X\n", READ_U16());
     } break;
     default:
-      fprintf(stderr, "unrecognized opcode: %02X\n", op);
-      exit(1);
+      printf("???\n");
     }
   }
 }