211 lines
7.6 KiB
PHP
211 lines
7.6 KiB
PHP
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if (!strlen(astr)) {
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//Implied instructions
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if (!strcmp(ins,"BRK")) opcode[0] = 0x00;
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else if (!strcmp(ins,"PHP")) opcode[0] = 0x08;
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else if (!strcmp(ins,"ASL")) opcode[0] = 0x0A;
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else if (!strcmp(ins,"CLC")) opcode[0] = 0x18;
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else if (!strcmp(ins,"PLP")) opcode[0] = 0x28;
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else if (!strcmp(ins,"ROL")) opcode[0] = 0x2A;
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else if (!strcmp(ins,"SEC")) opcode[0] = 0x38;
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else if (!strcmp(ins,"RTI")) opcode[0] = 0x40;
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else if (!strcmp(ins,"PHA")) opcode[0] = 0x48;
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else if (!strcmp(ins,"LSR")) opcode[0] = 0x4A;
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else if (!strcmp(ins,"CLI")) opcode[0] = 0x58;
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else if (!strcmp(ins,"RTS")) opcode[0] = 0x60;
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else if (!strcmp(ins,"PLA")) opcode[0] = 0x68;
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else if (!strcmp(ins,"ROR")) opcode[0] = 0x6A;
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else if (!strcmp(ins,"SEI")) opcode[0] = 0x78;
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else if (!strcmp(ins,"DEY")) opcode[0] = 0x88;
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else if (!strcmp(ins,"TXA")) opcode[0] = 0x8A;
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else if (!strcmp(ins,"TYA")) opcode[0] = 0x98;
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else if (!strcmp(ins,"TXS")) opcode[0] = 0x9A;
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else if (!strcmp(ins,"TAY")) opcode[0] = 0xA8;
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else if (!strcmp(ins,"TAX")) opcode[0] = 0xAA;
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else if (!strcmp(ins,"CLV")) opcode[0] = 0xB8;
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else if (!strcmp(ins,"TSX")) opcode[0] = 0xBA;
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else if (!strcmp(ins,"INY")) opcode[0] = 0xC8;
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else if (!strcmp(ins,"DEX")) opcode[0] = 0xCA;
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else if (!strcmp(ins,"CLD")) opcode[0] = 0xD8;
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else if (!strcmp(ins,"INX")) opcode[0] = 0xE8;
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else if (!strcmp(ins,"NOP")) opcode[0] = 0xEA;
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else if (!strcmp(ins,"SED")) opcode[0] = 0xF8;
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else return 1;
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}
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else {
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//Instructions with Operands
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if (!strcmp(ins,"ORA")) opcode[0] = 0x01;
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else if (!strcmp(ins,"ASL")) opcode[0] = 0x06;
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else if (!strcmp(ins,"BPL")) opcode[0] = 0x10;
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else if (!strcmp(ins,"JSR")) opcode[0] = 0x20;
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else if (!strcmp(ins,"AND")) opcode[0] = 0x21;
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else if (!strcmp(ins,"BIT")) opcode[0] = 0x24;
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else if (!strcmp(ins,"ROL")) opcode[0] = 0x26;
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else if (!strcmp(ins,"BMI")) opcode[0] = 0x30;
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else if (!strcmp(ins,"EOR")) opcode[0] = 0x41;
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else if (!strcmp(ins,"LSR")) opcode[0] = 0x46;
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else if (!strcmp(ins,"JMP")) opcode[0] = 0x4C;
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else if (!strcmp(ins,"BVC")) opcode[0] = 0x50;
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else if (!strcmp(ins,"ADC")) opcode[0] = 0x61;
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else if (!strcmp(ins,"ROR")) opcode[0] = 0x66;
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else if (!strcmp(ins,"BVS")) opcode[0] = 0x70;
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else if (!strcmp(ins,"STA")) opcode[0] = 0x81;
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else if (!strcmp(ins,"STY")) opcode[0] = 0x84;
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else if (!strcmp(ins,"STX")) opcode[0] = 0x86;
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else if (!strcmp(ins,"BCC")) opcode[0] = 0x90;
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else if (!strcmp(ins,"LDY")) opcode[0] = 0xA0;
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else if (!strcmp(ins,"LDA")) opcode[0] = 0xA1;
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else if (!strcmp(ins,"LDX")) opcode[0] = 0xA2;
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else if (!strcmp(ins,"BCS")) opcode[0] = 0xB0;
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else if (!strcmp(ins,"CPY")) opcode[0] = 0xC0;
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else if (!strcmp(ins,"CMP")) opcode[0] = 0xC1;
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else if (!strcmp(ins,"DEC")) opcode[0] = 0xC6;
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else if (!strcmp(ins,"BNE")) opcode[0] = 0xD0;
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else if (!strcmp(ins,"CPX")) opcode[0] = 0xE0;
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else if (!strcmp(ins,"SBC")) opcode[0] = 0xE1;
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else if (!strcmp(ins,"INC")) opcode[0] = 0xE6;
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else if (!strcmp(ins,"BEQ")) opcode[0] = 0xF0;
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else return 1;
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{
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//Parse Operands
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// It's not the sexiest thing ever, but it works well enough!
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//TODO:
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// Add branches.
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// Fix certain instructions. (Setting bits is not 100% perfect.)
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// Fix instruction/operand matching. (Instructions like "jmp ($94),Y" are no good!)
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// Optimizations?
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int tmpint;
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char tmpchr,tmpstr[20];
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if (sscanf(astr,"#$%2X%c",&tmpint,&tmpchr) == 1) { //#Immediate
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switch (opcode[0]) {
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case 0x20: case 0x4C: //Jumps
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case 0x10: case 0x30: case 0x50: case 0x70: //Branches
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case 0x90: case 0xB0: case 0xD0: case 0xF0:
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case 0x06: case 0x24: case 0x26: case 0x46: //Other instructions incapable of #Immediate
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case 0x66: case 0x81: case 0x84: case 0x86:
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case 0xC6: case 0xE6:
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return 1;
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default:
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//cheap hack for certain instructions
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switch (opcode[0]) {
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case 0xA0: case 0xA2: case 0xC0: case 0xE0:
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break;
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default:
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opcode[0] |= 0x08;
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break;
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}
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opcode[1] = tmpint;
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break;
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}
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}
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else if (sscanf(astr,"$%4X%c",&tmpint,&tmpchr) == 1) { //Absolute, Zero Page, Branch, or Jump
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switch (opcode[0]) {
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case 0x20: case 0x4C: //Jumps
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opcode[1] = (tmpint & 0xFF);
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opcode[2] = (tmpint >> 8);
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break;
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case 0x10: case 0x30: case 0x50: case 0x70: //Branches
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case 0x90: case 0xB0: case 0xD0: case 0xF0:
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tmpint -= (addr+2);
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if ((tmpint < -128) || (tmpint > 127)) return 1;
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opcode[1] = (tmpint & 0xFF);
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break;
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//return 1; //FIX ME
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default:
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if (tmpint > 0xFF) { //Absolute
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opcode[0] |= 0x0C;
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opcode[1] = (tmpint & 0xFF);
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opcode[2] = (tmpint >> 8);
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}
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else { //Zero Page
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opcode[0] |= 0x04;
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opcode[1] = (tmpint & 0xFF);
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}
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break;
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}
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}
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else if (sscanf(astr,"$%4X%s",&tmpint,tmpstr) == 2) { //Absolute,X, Zero Page,X, Absolute,Y or Zero Page,Y
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if (!strcmp(tmpstr,",X")) { //Absolute,X or Zero Page,X
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switch (opcode[0]) {
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case 0x20: case 0x4C: //Jumps
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case 0x10: case 0x30: case 0x50: case 0x70: //Branches
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case 0x90: case 0xB0: case 0xD0: case 0xF0:
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case 0x24: case 0x86: case 0xA2: case 0xC0: //Other instructions incapable of Absolute,X or Zero Page,X
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case 0xE0:
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return 1;
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default:
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if (tmpint > 0xFF) { //Absolute
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if (opcode[0] == 0x84) return 1; //No STY Absolute,X!
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opcode[0] |= 0x1C;
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opcode[1] = (tmpint & 0xFF);
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opcode[2] = (tmpint >> 8);
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}
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else { //Zero Page
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opcode[0] |= 0x14;
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opcode[1] = (tmpint & 0xFF);
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}
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break;
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}
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}
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else if (!strcmp(tmpstr,",Y")) { //Absolute,Y or Zero Page,Y
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switch (opcode[0]) {
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case 0x20: case 0x4C: //Jumps
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case 0x10: case 0x30: case 0x50: case 0x70: //Branches
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case 0x90: case 0xB0: case 0xD0: case 0xF0:
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case 0x06: case 0x24: case 0x26: case 0x46: //Other instructions incapable of Absolute,Y or Zero Page,Y
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case 0x66: case 0x84: case 0x86: case 0xA0:
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case 0xC0: case 0xC6: case 0xE0: case 0xE6:
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return 1;
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case 0xA2: //cheap hack for LDX
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opcode[0] |= 0x04;
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default:
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if (tmpint > 0xFF) { //Absolute
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if (opcode[0] == 0x86) return 1; //No STX Absolute,Y!
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opcode[0] |= 0x18;
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opcode[1] = (tmpint & 0xFF);
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opcode[2] = (tmpint >> 8);
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}
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else { //Zero Page
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if ((opcode[0] != 0x86) || (opcode[0] != 0xA2)) return 1; //only STX and LDX Absolute,Y!
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opcode[0] |= 0x10;
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opcode[1] = (tmpint & 0xFF);
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}
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break;
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}
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}
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else return 1;
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}
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else if (sscanf(astr,"($%4X%s",&tmpint,tmpstr) == 2) { //Jump (Indirect), (Indirect,X) or (Indirect),Y
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switch (opcode[0]) {
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case 0x20: //Jumps
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case 0x10: case 0x30: case 0x50: case 0x70: //Branches
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case 0x90: case 0xB0: case 0xD0: case 0xF0:
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case 0x06: case 0x24: case 0x26: case 0x46: //Other instructions incapable of Jump (Indirect), (Indirect,X) or (Indirect),Y
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case 0x66: case 0x84: case 0x86: case 0xA0:
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case 0xA2: case 0xC0: case 0xC6: case 0xE0:
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case 0xE6:
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return 1;
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default:
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if ((!strcmp(tmpstr,")")) && (opcode[0] == 0x4C)) { //Jump (Indirect)
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opcode[0] = 0x6C;
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opcode[1] = (tmpint & 0xFF);
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opcode[2] = (tmpint >> 8);
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}
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else if ((!strcmp(tmpstr,",X)")) && (tmpint <= 0xFF) && (opcode[0] != 0x4C)) { //(Indirect,X)
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opcode[1] = (tmpint & 0xFF);
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}
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else if ((!strcmp(tmpstr,"),Y")) && (tmpint <= 0xFF) && (opcode[0] != 0x4C)) { //(Indirect),Y
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opcode[0] |= 0x10;
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opcode[1] = (tmpint & 0xFF);
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}
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else return 1;
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break;
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}
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}
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else return 1;
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}
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}
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