all opcodes decoded

src/6502.c

@@ -1,9 +1,10 @@
+#include <stdio.h>
+
 #include "inc/types.h"
 #include "inc/memory.h"
 #include "inc/opcodes.h"
 
-oc1 opcode_decoded_1;
+
-oc2 opcode_decoded_2;
 
 void init()
 {
@@ -38,11 +39,128 @@ void decode()
     
     opcode_decoded_1 = aaacc;
     opcode_decoded_2 = ir;
+    
+    addressing_mode = bbb;
+    
+    if (cc == 0b01)
+    {
+        // correct the addressing mode for '01' opcodetype
+        if (bbb == 0b000)
+        {
+            addressing_mode = indirect_x;
+        }
+        if (bbb == 0b010)
+        {
+            addressing_mode = immediate;
+        }
+    }
+    
+    if (cc == 0b10)
+    {
+        // adjust the addressing mode for STX and LDX
+        if ((opcode_decoded_1 == STX || opcode_decoded_1 == LDX) && addressing_mode == zero_page_x)
+        {
+            addressing_mode = zero_page_y;
+        }
+        if (opcode_decoded_1 == LDX && addressing_mode == absolute_x)
+        {
+            addressing_mode = absolute_y;
+        }
+    }
+    
+    // disable all incorrect opcodes
+    if (((ir & 0x0F) == 0x02 && ir != 0xA2) ||
+         (ir & 0x0F) == 0x03 || (ir & 0x0F) == 0x07 ||
+         (ir & 0x0F) == 0x0B || (ir & 0x0F) == 0x0F)
+    {
+        opcode_decoded_1 = XXX;
+        opcode_decoded_2 = XXX;
+    }
+    
+    if (ir == 0x04 || ir == 0x0C || ir == 0x14 || ir == 0x1A || ir == 0x1C || ir == 0x34 || ir == 0x3A ||
+        ir == 0x3C || ir == 0x44 || ir == 0x54 || ir == 0x5A || ir == 0x5C || ir == 0x64 || ir == 0x74 ||
+        ir == 0x7A || ir == 0x7C || ir == 0x80 || ir == 0x89 || ir == 0x9C || ir == 0x9E ||
+        ir == 0xD4 || ir == 0xDA || ir == 0xDC || ir == 0xF4 || ir == 0xFA || ir == 0xFC)
+    {
+        opcode_decoded_1 = XXX;
+        opcode_decoded_2 = XXX;
+    }
 }
 
 void execute()
 {
-    switch(opcode_decoded_2)
+    /*switch (opcode_decoded_2)
+    {
+        case JSR:
+            printf("abs ");
+            pc++;
+            pc++;
+            break;
+        case BPL: case BMI: case BVC: case BVS:
+        case BCC: case BCS: case BNE: case BEQ:
+            printf("rel ");
+            pc++;
+            break;
+        case TXA: case TXS: case TAX: case TSX: case DEX:
+        case NOP: case CLC: case SEC: case CLI: case SEI:
+        case TYA: case CLV: case CLD: case SED: case PHP:
+        case PLP: case PHA: case PLA: case DEY: case TAY:
+        case INY: case INX: case BRK: case RTI: case RTS:
+            printf("imp ");
+            break;
+        default:
+            switch (addressing_mode)
+            {
+                case immediate:
+                    printf("imm ");
+                    pc++;
+                    break;
+                case zero_page:
+                    printf("zpg ");
+                    pc++;
+                    break;
+                case accumulator:
+                    printf("acc ");
+                    break;
+                case absolute:
+                    printf("abs ");
+                    pc++;
+                    pc++;
+                    break;
+                case indirect_y:
+                    printf("iny ");
+                    pc++;
+                    break;
+                case zero_page_x:
+                    printf("zpx ");
+                    pc++;
+                    break;
+                case absolute_y:
+                    printf("aby ");
+                    pc++;
+                    pc++;
+                    break;
+                case absolute_x:
+                    printf("abx ");
+                    pc++;
+                    pc++;
+                    break;
+                case indirect_x:
+                    printf("inx ");
+                    pc++;
+                    break;
+                case zero_page_y:
+                    printf("zpy ");
+                    pc++;
+                    break;
+                default:
+                    
+                    break;
+            }
+            break;
+    }*/  
+
+    switch (opcode_decoded_2)
     {
         case BRK:
             return brk();
@@ -112,6 +230,8 @@ void execute()
             return dex();
         case NOP:
             return nop();
+        case XXX:
+            return xxx();
     }
     
     switch (opcode_decoded_1)
@@ -162,15 +282,22 @@ void execute()
             return dec();
         case INC:
             return inc();
+        case XXX:
+            return xxx();
     }
 }
 
 void run()
 {
-    while (pc != 0)
+    //while (pc != 0)
     {
-        fetch();
+        //fetch();
-        decode();
+        for (int i = 0x00; i <= 0xFF; i++)
-        execute();
+        {
+            ir = i;
+            decode();
+            execute();
+        }
     }
+    
 }

src/inc/opcodes.h

@@ -76,12 +76,34 @@ enum opcodes_comp
     TAX = 0xAA,
     TSX = 0xBA,
     DEX = 0xCA,
-    NOP = 0xEA
+    NOP = 0xEA,
+    
+    XXX = 0xFF
+};
+
+enum address_mode
+{
+    immediate   = 0b000,
+    zero_page   = 0b001,
+    accumulator = 0b010,
+    absolute    = 0b011,
+    indirect_y  = 0b100,
+    zero_page_x = 0b101,
+    absolute_y  = 0b110,
+    absolute_x  = 0b111,
+    indirect_x,
+    zero_page_y
 };
 
 typedef enum opcodes oc1;
 typedef enum opcodes_comp oc2;
+typedef enum address_mode am;
 
+oc1 opcode_decoded_1;
+oc2 opcode_decoded_2;
+am addressing_mode;
+
+void xxx(); // invalid opcode
 void adc(); // add memory to accumalator with carry
 void and(); // and memory with accumulator
 void asl(); // shift left one bit (memory on accumulator)

src/opcodes.c

@@ -2,338 +2,464 @@
 
 #include "inc/opcodes.h"
 
+int zz = 0;
+
+void decode_addressing_mode()
+{
+    switch (opcode_decoded_2)
+    {
+        case XXX:
+            printf("/---]  ");
+            break;
+        case JSR:
+            printf("/abs]  ");
+            break;
+        case BPL: case BMI: case BVC: case BVS:
+        case BCC: case BCS: case BNE: case BEQ:
+            printf("/rel]  ");
+            break;
+        case TXA: case TXS: case TAX: case TSX: case DEX:
+        case NOP: case CLC: case SEC: case CLI: case SEI:
+        case TYA: case CLV: case CLD: case SED: case PHP:
+        case PLP: case PHA: case PLA: case DEY: case TAY:
+        case INY: case INX: case BRK: case RTI: case RTS:
+            printf("/imp]  ");
+            break;
+        default:
+            switch (addressing_mode)
+            {
+                case immediate:
+                    printf("/imm]  ");
+                    break;
+                case zero_page:
+                    printf("/zpg]  ");
+                    break;
+                case accumulator:
+                    printf("/acc]  ");
+                    break;
+                case absolute:
+                    printf("/abs]  ");
+                    break;
+                case indirect_y:
+                    printf("/iny]  ");
+                    break;
+                case zero_page_x:
+                    printf("/zpx]  ");
+                    break;
+                case absolute_y:
+                    printf("/aby]  ");
+                    break;
+                case absolute_x:
+                    printf("/abx]  ");
+                    break;
+                case indirect_x:
+                    printf("/inx]  ");
+                    break;
+                case zero_page_y:
+                    printf("/zpy]  ");
+                    break;
+            }
+            break;
+    }
+    
+    if (++zz % 8 == 0) { printf("\n"); }
+}
+
+void xxx()
+{
+    // invalid opcode
+    printf("%02X:[---", ir);
+    decode_addressing_mode();
+}
+
 void adc()
 {
     // add memory to accumalator with carry
-    printf("ADC\n");
+    printf("%02X:[ADC", ir);
+    decode_addressing_mode();
 }
 
 void and()
 {
     // and memory with accumulator
-    printf("AND\n");
+    printf("%02X:[AND", ir);
+    decode_addressing_mode();
 }
 
 void asl()
 {
     // shift left one bit (memory on accumulator)
-    printf("ASL\n");
+    printf("%02X:[ASL", ir);
+    decode_addressing_mode();
 }
 
 void bcc()
 {
     // branch on carry clear
-    printf("BCC\n");
+    printf("%02X:[BCC", ir);
+    decode_addressing_mode();
 }
 
 void bcs()
 {
     // branch on carry set
-    printf("BSC\n");
+    printf("%02X:[BSC", ir);
+    decode_addressing_mode();
 }
 
 void beq()
 {
     // branch on result zero
-    printf("BEQ\n");
+    printf("%02X:[BEQ", ir);
+    decode_addressing_mode();
 }
 
 void bit()
 {
     // test bits in memory with accumulator
-    printf("BIT\n");
+    printf("%02X:[BIT", ir);
+    decode_addressing_mode();
 }
 
 void bmi()
 {
     // branch on result minus
-    printf("BMI\n");
+    printf("%02X:[BMI", ir);
+    decode_addressing_mode();
 }
 
 void bne()
 {
     // branch on result not zero
-    printf("BNE\n");
+    printf("%02X:[BNE", ir);
+    decode_addressing_mode();
 }
 
 void bpl()
 {
     // branch on result plus
-    printf("BPL\n");
+    printf("%02X:[BPL", ir);
+    decode_addressing_mode();
 }
 
 void brk()
 {
     // force break
-    printf("BRK\n");
+    printf("%02X:[BRK", ir);
+    decode_addressing_mode();
 }
 
 void bvc()
 {
     // branch on overflow clear
-    printf("BVC\n");
+    printf("%02X:[BVC", ir);
+    decode_addressing_mode();
 }
 
 void bvs()
 {
     // branch on overflow set
-    printf("BVS\n");
+    printf("%02X:[BVS", ir);
+    decode_addressing_mode();
 }
 
 void clc()
 {
     // clear carry flag
-    printf("CLC\n");
+    printf("%02X:[CLC", ir);
+    decode_addressing_mode();
 }
 
 void cld()
 {
     // clear decimal mode
-    printf("CLD\n");
+    printf("%02X:[CLD", ir);
+    decode_addressing_mode();
 }
 
 void cli()
 {
     // clear interrupt disable bit
-    printf("CLI\n");
+    printf("%02X:[CLI", ir);
+    decode_addressing_mode();
 }
 
 void clv()
 {
     // clear overflow flag
-    printf("CLV\n");
+    printf("%02X:[CLV", ir);
+    decode_addressing_mode();
 }
 
 void cmp()
 {
     // compare memory with accumulator
-    printf("CMP\n");
+    printf("%02X:[CMP", ir);
+    decode_addressing_mode();
 }
 
 void cpx()
 {
     // compare memory and index x
-    printf("CPX\n");
+    printf("%02X:[CPX", ir);
+    decode_addressing_mode();
 }
 
 void cpy()
 {
     // compare memory and index y
-    printf("CPY\n");
+    printf("%02X:[CPY", ir);
+    decode_addressing_mode();
 }
 
 void dec()
 {
     // decrement memory by one
-    printf("DEC\n");
+    printf("%02X:[DEC", ir);
+    decode_addressing_mode();
 }
 
 void dex()
 {
     // decrement index x by one
-    printf("DEX\n");
+    printf("%02X:[DEX", ir);
+    decode_addressing_mode();
 }
 
 void dey()
 {
     // decrement index y by one
-    printf("DEY\n");
+    printf("%02X:[DEY", ir);
+    decode_addressing_mode();
 }
 
 void eor()
 {
     // exclusive-or memory with accumulator
-    printf("EOR\n");
+    printf("%02X:[EOR", ir);
+    decode_addressing_mode();
 }
 
 void inc()
 {
     // increment memory by one
-    printf("INC\n");
+    printf("%02X:[INC", ir);
+    decode_addressing_mode();
 }
 
 void inx()
 {
     // increment index x by one
-    printf("INX\n");
+    printf("%02X:[INX", ir);
+    decode_addressing_mode();
 }
 
 void iny()
 {
     // increment index y by one
-    printf("INY\n");
+    printf("%02X:[INY", ir);
+    decode_addressing_mode();
 }
 
 void jmp()
 {
     // jump to new location
-    printf("JMP\n");
+    printf("%02X:[JMP", ir);
+    decode_addressing_mode();
 }
 
 void jsr()
 {
     // jump to new location saving return address
-    printf("JSR\n");
+    printf("%02X:[JSR", ir);
+    decode_addressing_mode();
 }
 
 void lda()
 {
     // load accumulator with memory
-    printf("LDA\n");
+    printf("%02X:[LDA", ir);
+    decode_addressing_mode();
 }
 
 void ldx()
 {
     // load index x with memory
-    printf("LDX\n");
+    printf("%02X:[LDX", ir);
+    decode_addressing_mode();
 }
 
 void ldy()
 {
     // load index y with memory
-    printf("LDY\n");
+    printf("%02X:[LDY", ir);
+    decode_addressing_mode();
 }
 
 void lsr()
 {
     // shift one bit right (memory or accumulator)
-    printf("LSR\n");
+    printf("%02X:[LSR", ir);
+    decode_addressing_mode();
 }
 
 void nop()
 {
     // no operation
-    printf("NOP\n");
+    printf("%02X:[NOP", ir);
+    decode_addressing_mode();
 }
 
 void ora()
 {
     // or memory with accumulator
-    printf("ORA\n");
+    printf("%02X:[ORA", ir);
+    decode_addressing_mode();
 }
 
 void pha()
 {
     // push accumulator on stack
-    printf("PHA\n");
+    printf("%02X:[PHA", ir);
+    decode_addressing_mode();
 }
 
 void php()
 {
     // push processor status on stack
-    printf("PHP\n");
+    printf("%02X:[PHP", ir);
+    decode_addressing_mode();
 }
 
 void pla()
 {
     // pull accumulator from stack
-    printf("PLA\n");
+    printf("%02X:[PLA", ir);
+    decode_addressing_mode();
 }
 
 void plp()
 {
     // pull processor status from stack
-    printf("PLP\n");
+    printf("%02X:[PLP", ir);
+    decode_addressing_mode();
 }
 
 void rol()
 {
     // rotate on bit left (memory or accumulator)
-    printf("ROL\n");
+    printf("%02X:[ROL", ir);
+    decode_addressing_mode();
 }
 
 void ror()
 {
     // rotate on bit right (memory or accumulator)
-    printf("ROR\n");
+    printf("%02X:[ROR", ir);
+    decode_addressing_mode();
 }
 
 void rti()
 {
     // return from interrupt
-    printf("RTI\n");
+    printf("%02X:[RTI", ir);
+    decode_addressing_mode();
 }
 
 void rts()
 {
     // retrun from subroutine
-    printf("RTS\n");
+    printf("%02X:[RTS", ir);
+    decode_addressing_mode();
 }
 
 void sbc()
 {
     // subtract memory from accumulator with borrow
-    printf("SBC\n");
+    printf("%02X:[SBC", ir);
+    decode_addressing_mode();
 }
 
 void sec()
 {
     // set carry flag
-    printf("SEC\n");
+    printf("%02X:[SEC", ir);
+    decode_addressing_mode();
 }
 
 void sed()
 {
     // set decimal flag
-    printf("SED\n");
+    printf("%02X:[SED", ir);
+    decode_addressing_mode();
 }
 
 void sei()
 {
     // set interrupt disable status
-    printf("SEI\n");
+    printf("%02X:[SEI", ir);
+    decode_addressing_mode();
 }
 
 void sta()
 {
     // store accumulator in memory
-    printf("STA\n");
+    printf("%02X:[STA", ir);
+    decode_addressing_mode();
 }
 
 void stx()
 {
     // store index x in memory
-    printf("STX\n");
+    printf("%02X:[STX", ir);
+    decode_addressing_mode();
 }
 
 void sty()
 {
     // store index y in memory
-    printf("STY\n");
+    printf("%02X:[STY", ir);
+    decode_addressing_mode();
 }
 
 void tax()
 {
     // transfer accumulator to index x
-    printf("TAX\n");
+    printf("%02X:[TAX", ir);
+    decode_addressing_mode();
 }
 
 void tay()
 {
     // transfer accumulator to index y
-    printf("TAY\n");
+    printf("%02X:[TAY", ir);
+    decode_addressing_mode();
 }
 
 void tsx()
 {
     // transfer stack pointer to index x
-    printf("TSX\n");
+    printf("%02X:[TSX", ir);
+    decode_addressing_mode();
 }
 
 void txa()
 {
     // transfer index x to accumulator
-    printf("TXA\n");
+    printf("%02X:[TXA", ir);
+    decode_addressing_mode();
 }
 
 void txs()
 {
     // transfer index x to stack pointer
-    printf("TXS\n");
+    printf("%02X:[TXS", ir);
+    decode_addressing_mode();
 }
 
 void tya()
 {
     // transfer index y to accumulator
-    printf("TYA\n");
+    printf("%02X:[TYA", ir);
+    decode_addressing_mode();
 }