6502/65816.js
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added BRL

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Preston Skupinski 2011-05-12 00:09:02 -04:00
parent 6acdd0d596
commit b4f795f368
1 changed files with 17 additions and 1 deletions
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18
cpu.js
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@ -77,7 +77,7 @@ function CPU_65816() {
0x74 : STZ_direct_page_indexed_x, 0x9b : TXY,
0xbb : TYX, 0xaa : TAX, 0xa8 : TAY, 0x8a : TXA,
0x98 : TYA, 0x4c : JMP_absolute,
0x6c : JMP_absolute_indirect, 0x80 : BRA,
0x6c : JMP_absolute_indirect, 0x80 : BRA, 0x82 : BRL,
0xf0 : BEQ, 0xd0 : BNE, 0x90 : BCC, 0xb0 : BCS,
0x50 : BVC, 0x70 : BVS, 0x10 : BPL, 0x30 : BMI,
0x69 : ADC_const, 0x6d : ADC_absolute,
@ -2074,6 +2074,22 @@ var BRA = {
}
};
var BRL = {
bytes_required:function() {
return 3;
},
execute:function(cpu, bytes) {
// Handle double byte two's complement numbers as the branch argument.
var num = (bytes[1]<<8)|bytes[0];
if(num<=32767) {
cpu.r.pc+=num;
} else {
cpu.r.pc-=65536-num;
}
}
};
var JMP_absolute_indirect = {
bytes_required:function() {
return 3;