add preliminary implementation of the unofficial opcodes

3 files changed, 111 insertions, 88 deletions

diff --git a/cpu.c b/cpu.c
index e3bb7d5..039337f 100644
--- a/cpu.c
+++ b/cpu.c
@@ -128,8 +128,8 @@ opcode_mem(enum addressing_mode mode)
                 break;
         case AM_REL:
                 val = arg + regs.pc;
-                if ((regs.pc + 1) & 0xFF00 != val & 0xFF00)
-                        page_crossed = true;
+                if (((regs.pc + 1) & 0xFF00) != (val & 0xFF00))
+                        val -= 0x0100;
                 break;
         case AM_IMM:
         case AM_ABS:
@@ -703,133 +703,158 @@ TYA(uint16_t arg)
 void
 AAC(uint16_t arg)
 {
-        NOP(0);
+        AND(arg);
+
+        regs.status.carry = regs.status.negative;
 }
 
 void
-AAX(uint16_t arg)
+SAX(uint16_t arg)
 {
-        NOP(0);
+        uint8_t tmp = regs.x & regs.a;
+        memwrite(arg, tmp);
 }
 
 void
 ARR(uint16_t arg)
 {
-        NOP(0);
+        uint8_t tmp = arg & regs.a;
+
+        AND(arg);
+        ROR_acc(0);
+
+        if ((tmp & (1 << 5)) != 0 && (tmp & (1 << 6)) != 0)
+                SEC(0), CLV(0);
+        else if ((tmp & (1 << 5)) == 0 && (tmp & (1 << 6)) == 0)
+                CLC(0), CLV(0);
+        else if ((tmp & (1 << 5)) != 0)
+                CLC(0), regs.status.overflow = 1;
+        else if ((tmp & (1 << 6)) != 0)
+                SEC(0), regs.status.overflow = 1;
 }
 
 void
 ASR(uint16_t arg)
 {
-        NOP(0);
+        AND(arg);
+        LSR_acc(0);
 }
 
 void
 ATX(uint16_t arg)
 {
-        NOP(0);
+        AND(arg);
+        TAX(0);
 }
 
 void
 AXA(uint16_t arg)
 {
-        NOP(0);
+        uint8_t tmp = regs.x & regs.a & 7;
+        memwrite(arg, tmp);
 }
 
 void
 AXS(uint16_t arg)
 {
-        NOP(0);
+        regs.x &= regs.a;
+        regs.x -= arg;
+
+        regs.status.carry = arg <= regs.x;
+        STATUS_UPDATE_NZ(regs.x);
 }
 
 void
 DCP(uint16_t arg)
 {
-        NOP(0);
-}
+        uint8_t tmp = peek(arg) - 1;
+        memwrite(arg, tmp);
 
-void
-DOP(uint16_t arg)
-{
-        NOP(0);
+        regs.status.carry = tmp <= regs.a;
+        STATUS_UPDATE_NZ(tmp);
 }
 
 void
 ISC(uint16_t arg)
 {
-        NOP(0);
+        INC(arg);
+        SBC(peek(arg));
 }
 
 void
 KIL(uint16_t arg)
 {
+        /* TODO: figure out how to stop interpret(), I guess with global bool */
         NOP(0);
 }
 
 void
 LAR(uint16_t arg)
 {
-        NOP(0);
+        regs.a = regs.x = regs.sp = regs.a & regs.sp;
+
+        STATUS_UPDATE_NZ(regs.a);
 }
 
 void
 LAX(uint16_t arg)
 {
-        NOP(0);
+        LDA(arg);
+        LDX(arg);
 }
 
 void
 RLA(uint16_t arg)
 {
-        NOP(0);
+        ROL(arg);
+        AND(arg);
 }
 
 void
 RRA(uint16_t arg)
 {
-        NOP(0);
+        ROR(arg);
+        ADC(peek(arg));
 }
 
 void
 SLO(uint16_t arg)
 {
-        NOP(0);
+        ASL(arg);
+        ORA(arg);
 }
 
 void
 SRE(uint16_t arg)
 {
-        NOP(0);
+        LSR(arg);
+        EOR(arg);
 }
 
 void
 SXA(uint16_t arg)
 {
-        NOP(0);
+        memwrite(arg, regs.x & ((arg & 0xFF00) + 1));
 }
 
 void
 SYA(uint16_t arg)
 {
-        NOP(0);
-}
-
-void
-TOP(uint16_t arg)
-{
-        NOP(0);
+        memwrite(arg, regs.x & ((arg & 0xFF00) + 1));
 }
 
 void
 XAA(uint16_t arg)
 {
+        /* TODO: apparently the exact operation is unknown */
         NOP(0);
 }
 
 void
 XAS(uint16_t arg)
 {
-        NOP(0);
+        regs.sp = regs.a & regs.x;
+        memwrite(arg, regs.sp & ((arg & 0xFF00) + 1));
 }
 
 static void
@@ -877,8 +902,6 @@ interpret(void)
                         printf("$%02X,Y", arg);
                         break;
                 case AM_REL:
-                        printf("$%04X", regs.pc + arg);
-                        break;
                 case AM_ABS:
                         printf("$%04X", arg);
                         break;
diff --git a/cpu.h b/cpu.h
index b7cab89..3002573 100644
--- a/cpu.h
+++ b/cpu.h
@@ -64,7 +64,7 @@ void TYA(uint16_t arg);
 
 /* UNOFFICIAL OPCODES */
 void AAC(uint16_t arg);
-void AAX(uint16_t arg);
+void SAX(uint16_t arg);
 void ARR(uint16_t arg);
 void ASR(uint16_t arg);
 void ATX(uint16_t arg);
diff --git a/opcodes.h b/opcodes.h
index ca0d1cc..020e8f3 100644
--- a/opcodes.h
+++ b/opcodes.h
@@ -189,23 +189,23 @@ struct opcode opcodes[0x100] = {
         /* unofficial opcodes: https://www.nesdev.org/undocumented_opcodes.txt */
         [0x0B] = { "AAC", AAC, 2, 2, false, false, false, true,  AM_IMM },
         [0x2B] = { "AAC", AAC, 2, 2, false, false, false, true,  AM_IMM },
-        [0x87] = { "AAX", AAX, 2, 3, false, false, false, true,  AM_ZP },
-        [0x97] = { "AAX", AAX, 2, 4, false, false, false, true,  AM_ZP_Y },
-        [0x83] = { "AAX", AAX, 2, 6, false, false, false, true,  AM_IND_X },
-        [0x8F] = { "AAX", AAX, 3, 4, false, false, false, true,  AM_ABS },
+        [0x87] = { "SAX", SAX, 2, 3, false, true,  false, true,  AM_ZP },
+        [0x97] = { "SAX", SAX, 2, 4, false, true,  false, true,  AM_ZP_Y },
+        [0x83] = { "SAX", SAX, 2, 6, false, true,  false, true,  AM_IND_X },
+        [0x8F] = { "SAX", SAX, 3, 4, false, true,  false, true,  AM_ABS },
         [0x6B] = { "ARR", ARR, 2, 2, false, false, false, true,  AM_IMM },
         [0x4B] = { "ASR", ASR, 2, 2, false, false, false, true,  AM_IMM },
         [0xAB] = { "ATX", ATX, 2, 2, false, false, false, true,  AM_IMM },
-        [0x9F] = { "AXA", AXA, 3, 5, false, false, false, true,  AM_ABS_Y },
-        [0x93] = { "AXA", AXA, 2, 6, false, false, false, true,  AM_IND_Y },
+        [0x9F] = { "AXA", AXA, 3, 5, false, true,  false, true,  AM_ABS_Y },
+        [0x93] = { "AXA", AXA, 2, 6, false, true,  false, true,  AM_IND_Y },
         [0xCB] = { "AXS", AXS, 2, 2, false, false, false, true,  AM_IMM },
-        [0xC7] = { "DCP", DCP, 2, 5, false, false, false, true,  AM_ZP },
-        [0xD7] = { "DCP", DCP, 2, 6, false, false, false, true,  AM_ZP_X },
-        [0xCF] = { "DCP", DCP, 3, 6, false, false, false, true,  AM_ABS },
-        [0xDF] = { "DCP", DCP, 3, 7, false, false, false, true,  AM_ABS_X },
-        [0xDB] = { "DCP", DCP, 3, 7, false, false, false, true,  AM_ABS_Y },
-        [0xC3] = { "DCP", DCP, 2, 8, false, false, false, true,  AM_IND_X },
-        [0xD3] = { "DCP", DCP, 2, 8, false, false, false, true,  AM_IND_Y },
+        [0xC7] = { "DCP", DCP, 2, 5, false, true,  false, true,  AM_ZP },
+        [0xD7] = { "DCP", DCP, 2, 6, false, true,  false, true,  AM_ZP_X },
+        [0xCF] = { "DCP", DCP, 3, 6, false, true,  false, true,  AM_ABS },
+        [0xDF] = { "DCP", DCP, 3, 7, false, true,  false, true,  AM_ABS_X },
+        [0xDB] = { "DCP", DCP, 3, 7, false, true,  false, true,  AM_ABS_Y },
+        [0xC3] = { "DCP", DCP, 2, 8, false, true,  false, true,  AM_IND_X },
+        [0xD3] = { "DCP", DCP, 2, 8, false, true,  false, true,  AM_IND_Y },
         [0x04] = { "NOP", NOP, 2, 3, true,  false, false, true,  AM_ZP },
         [0x14] = { "NOP", NOP, 2, 4, true,  false, false, true,  AM_ZP_X },
         [0x34] = { "NOP", NOP, 2, 4, true,  false, false, true,  AM_ZP_X },
@@ -217,9 +217,9 @@ struct opcode opcodes[0x100] = {
         [0x82] = { "NOP", NOP, 2, 2, false, false, false, true,  AM_IMM },
         [0x89] = { "NOP", NOP, 2, 2, false, false, false, true,  AM_IMM },
         [0xC2] = { "NOP", NOP, 2, 2, false, false, false, true,  AM_IMM },
-        [0xD4] = { "NOP", NOP, 2, 4, false, false, false, true,  AM_ZP_X },
+        [0xD4] = { "NOP", NOP, 2, 4, true,  false, false, true,  AM_ZP_X },
         [0xE2] = { "NOP", NOP, 2, 2, false, false, false, true,  AM_IMM },
-        [0xF4] = { "NOP", NOP, 2, 4, false, false, false, true,  AM_ZP_X },
+        [0xF4] = { "NOP", NOP, 2, 4, true,  false, false, true,  AM_ZP_X },
         [0xE7] = { "ISC", ISC, 2, 5, false, false, false, true,  AM_ZP },
         [0xF7] = { "ISC", ISC, 2, 6, false, false, false, true,  AM_ZP_X },
         [0xEF] = { "ISC", ISC, 3, 6, false, false, false, true,  AM_ABS },
@@ -239,50 +239,50 @@ struct opcode opcodes[0x100] = {
         [0xB2] = { "KIL", KIL, 1, 0, false, false, false, true,  AM_NONE },
         [0xD2] = { "KIL", KIL, 1, 0, false, false, false, true,  AM_NONE },
         [0xF2] = { "KIL", KIL, 1, 0, false, false, false, true,  AM_NONE },
-        [0xBB] = { "LAR", LAR, 3, 4, false, false, true,  true,  AM_ABS_Y },
-        [0xA7] = { "LAX", LAX, 2, 3, false, false, false, true,  AM_ZP },
-        [0xB7] = { "LAX", LAX, 2, 4, false, false, false, true,  AM_ZP_Y },
-        [0xAF] = { "LAX", LAX, 3, 4, false, false, false, true,  AM_ABS },
-        [0xBF] = { "LAX", LAX, 3, 4, false, false, true,  true,  AM_ABS_Y },
-        [0xA3] = { "LAX", LAX, 2, 6, false, false, false, true,  AM_IND_X },
-        [0xB3] = { "LAX", LAX, 2, 5, false, false, true,  true,  AM_IND_Y },
+        [0xBB] = { "LAR", LAR, 3, 4, true,  false, true,  true,  AM_ABS_Y },
+        [0xA7] = { "LAX", LAX, 2, 3, true,  false, false, true,  AM_ZP },
+        [0xB7] = { "LAX", LAX, 2, 4, true,  false, false, true,  AM_ZP_Y },
+        [0xAF] = { "LAX", LAX, 3, 4, true,  false, false, true,  AM_ABS },
+        [0xBF] = { "LAX", LAX, 3, 4, true,  false, true,  true,  AM_ABS_Y },
+        [0xA3] = { "LAX", LAX, 2, 6, true,  false, false, true,  AM_IND_X },
+        [0xB3] = { "LAX", LAX, 2, 5, true,  false, true,  true,  AM_IND_Y },
         [0x1A] = { "NOP", NOP, 1, 2, false, false, false, true,  AM_NONE },
         [0x3A] = { "NOP", NOP, 1, 2, false, false, false, true,  AM_NONE },
         [0x5A] = { "NOP", NOP, 1, 2, false, false, false, true,  AM_NONE },
         [0x7A] = { "NOP", NOP, 1, 2, false, false, false, true,  AM_NONE },
         [0xDA] = { "NOP", NOP, 1, 2, false, false, false, true,  AM_NONE },
         [0xFA] = { "NOP", NOP, 1, 2, false, false, false, true,  AM_NONE },
-        [0x27] = { "RLA", RLA, 2, 5, false, false, false, true,  AM_ZP },
-        [0x37] = { "RLA", RLA, 2, 6, false, false, false, true,  AM_ZP_X },
-        [0x2F] = { "RLA", RLA, 3, 6, false, false, false, true,  AM_ABS },
-        [0x3F] = { "RLA", RLA, 3, 7, false, false, false, true,  AM_ABS_X },
-        [0x3B] = { "RLA", RLA, 3, 7, false, false, false, true,  AM_ABS_Y },
-        [0x23] = { "RLA", RLA, 2, 8, false, false, false, true,  AM_IND_X },
-        [0x33] = { "RLA", RLA, 2, 8, false, false, false, true,  AM_IND_Y },
-        [0x67] = { "RRA", RRA, 2, 5, false, false, false, true,  AM_ZP },
-        [0x77] = { "RRA", RRA, 2, 6, false, false, false, true,  AM_ZP_X },
-        [0x6F] = { "RRA", RRA, 3, 6, false, false, false, true,  AM_ABS },
-        [0x7F] = { "RRA", RRA, 3, 7, false, false, false, true,  AM_ABS_X },
-        [0x7B] = { "RRA", RRA, 3, 7, false, false, false, true,  AM_ABS_Y },
-        [0x63] = { "RRA", RRA, 2, 8, false, false, false, true,  AM_IND_X },
-        [0x73] = { "RRA", RRA, 2, 8, false, false, false, true,  AM_IND_Y },
+        [0x27] = { "RLA", RLA, 2, 5, true,  true,  false, true,  AM_ZP },
+        [0x37] = { "RLA", RLA, 2, 6, true,  true,  false, true,  AM_ZP_X },
+        [0x2F] = { "RLA", RLA, 3, 6, true,  true,  false, true,  AM_ABS },
+        [0x3F] = { "RLA", RLA, 3, 7, true,  true,  false, true,  AM_ABS_X },
+        [0x3B] = { "RLA", RLA, 3, 7, true,  true,  false, true,  AM_ABS_Y },
+        [0x23] = { "RLA", RLA, 2, 8, true,  true,  false, true,  AM_IND_X },
+        [0x33] = { "RLA", RLA, 2, 8, true,  true,  false, true,  AM_IND_Y },
+        [0x67] = { "RRA", RRA, 2, 5, true,  true,  false, true,  AM_ZP },
+        [0x77] = { "RRA", RRA, 2, 6, true,  true,  false, true,  AM_ZP_X },
+        [0x6F] = { "RRA", RRA, 3, 6, true,  true,  false, true,  AM_ABS },
+        [0x7F] = { "RRA", RRA, 3, 7, true,  true,  false, true,  AM_ABS_X },
+        [0x7B] = { "RRA", RRA, 3, 7, true,  true,  false, true,  AM_ABS_Y },
+        [0x63] = { "RRA", RRA, 2, 8, true,  true,  false, true,  AM_IND_X },
+        [0x73] = { "RRA", RRA, 2, 8, true,  true,  false, true,  AM_IND_Y },
         [0xEB] = { "SBC", SBC, 2, 2, false, false, false, true,  AM_IMM },
-        [0x07] = { "SLO", SLO, 2, 5, false, false, false, true,  AM_ZP },
-        [0x17] = { "SLO", SLO, 2, 6, false, false, false, true,  AM_ZP_X },
-        [0x0F] = { "SLO", SLO, 3, 6, false, false, false, true,  AM_ABS },
-        [0x1F] = { "SLO", SLO, 3, 7, false, false, false, true,  AM_ABS_X },
-        [0x1B] = { "SLO", SLO, 3, 7, false, false, false, true,  AM_ABS_Y },
-        [0x03] = { "SLO", SLO, 2, 8, false, false, false, true,  AM_IND_X },
-        [0x13] = { "SLO", SLO, 2, 8, false, false, false, true,  AM_IND_Y },
-        [0x47] = { "SRE", SRE, 2, 5, false, false, false, true,  AM_ZP },
-        [0x57] = { "SRE", SRE, 2, 6, false, false, false, true,  AM_ZP_X },
-        [0x4F] = { "SRE", SRE, 3, 6, false, false, false, true,  AM_ABS },
-        [0x5F] = { "SRE", SRE, 3, 7, false, false, false, true,  AM_ABS_X },
-        [0x5B] = { "SRE", SRE, 3, 7, false, false, false, true,  AM_ABS_Y },
-        [0x43] = { "SRE", SRE, 2, 8, false, false, false, true,  AM_IND_X },
-        [0x53] = { "SRE", SRE, 2, 8, false, false, false, true,  AM_IND_Y },
-        [0x9E] = { "SXA", SXA, 3, 5, false, false, false, true,  AM_ABS_Y },
-        [0x9C] = { "SYA", SYA, 3, 5, false, false, false, true,  AM_ABS_X },
+        [0x07] = { "SLO", SLO, 2, 5, true,  true,  false, true,  AM_ZP },
+        [0x17] = { "SLO", SLO, 2, 6, true,  true,  false, true,  AM_ZP_X },
+        [0x0F] = { "SLO", SLO, 3, 6, true,  true,  false, true,  AM_ABS },
+        [0x1F] = { "SLO", SLO, 3, 7, true,  true,  false, true,  AM_ABS_X },
+        [0x1B] = { "SLO", SLO, 3, 7, true,  true,  false, true,  AM_ABS_Y },
+        [0x03] = { "SLO", SLO, 2, 8, true,  true,  false, true,  AM_IND_X },
+        [0x13] = { "SLO", SLO, 2, 8, true,  true,  false, true,  AM_IND_Y },
+        [0x47] = { "SRE", SRE, 2, 5, true,  true,  false, true,  AM_ZP },
+        [0x57] = { "SRE", SRE, 2, 6, true,  true,  false, true,  AM_ZP_X },
+        [0x4F] = { "SRE", SRE, 3, 6, true,  true,  false, true,  AM_ABS },
+        [0x5F] = { "SRE", SRE, 3, 7, true,  true,  false, true,  AM_ABS_X },
+        [0x5B] = { "SRE", SRE, 3, 7, true,  true,  false, true,  AM_ABS_Y },
+        [0x43] = { "SRE", SRE, 2, 8, true,  true,  false, true,  AM_IND_X },
+        [0x53] = { "SRE", SRE, 2, 8, true,  true,  false, true,  AM_IND_Y },
+        [0x9E] = { "SXA", SXA, 3, 5, false, true,  false, true,  AM_ABS_Y },
+        [0x9C] = { "SYA", SYA, 3, 5, false, true,  false, true,  AM_ABS_X },
         [0x0C] = { "NOP", NOP, 3, 4, true,  false, false, true,  AM_ABS },
         [0x1C] = { "NOP", NOP, 3, 4, true,  false, true,  true,  AM_ABS_X },
         [0x3C] = { "NOP", NOP, 3, 4, true,  false, true,  true,  AM_ABS_X },
@@ -291,5 +291,5 @@ struct opcode opcodes[0x100] = {
         [0xDC] = { "NOP", NOP, 3, 4, true,  false, true,  true,  AM_ABS_X },
         [0xFC] = { "NOP", NOP, 3, 4, true,  false, true,  true,  AM_ABS_X },
         [0x8B] = { "XAA", XAA, 2, 2, false, false, false, true,  AM_IMM },
-        [0x9B] = { "XAS", XAS, 3, 5, false, false, false, true,  AM_ABS_Y },
+        [0x9B] = { "XAS", XAS, 3, 5, false, true,  false, true,  AM_ABS_Y },
 };