6502/65816.js
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added BIT immediate

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Preston Skupinski 2011-05-30 18:57:20 -04:00
parent 150d6e57d2
commit 71552b5720
2 changed files with 29 additions and 2 deletions
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1
TODO
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@ -19,7 +19,6 @@ Operations Not Yet Implemented:
- 0x42 : WDM
- 0x5c : JMP absolute long
- 0x7c : JMP absolute indexed x indirect
- 0x89 : BIT immediate
- 0x9a : TXS
- 0xba : TSX
- 0xcb : WAI

30
cpu.js
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@ -205,7 +205,7 @@ function CPU_65816() {
0x4b : PHK, 0x0b : PHD, 0x2b : PLD, 0x62 : PER,
0x20 : JSR, 0x60 : RTS, 0x22 : JSL, 0x6b : RTL,
0x54 : MVN, 0x44 : MVP, 0x00 : BRK, 0x40 : RTI,
0x02 : COP };
0x02 : COP, 0x89 : BIT_const };
/**
* Take a raw hex string representing the program and execute it.
@ -421,6 +421,34 @@ var MMU = {
}
};
var BIT_const = {
bytes_required:function(cpu) {
if(cpu.p.m)
return 2;
else
return 3;
},
execute:function(cpu, bytes) {
var and_result;
if(cpu.p.e|cpu.p.m) {
cpu.p.n = bytes[0] >> 7;
cpu.p.v = (bytes[0] >> 6) & 0x1;
and_result = cpu.r.a & bytes[0];
} else {
var argument = (bytes[1]<<8)|bytes[0];
cpu.p.n = bytes[1] >> 7;
cpu.p.v = (bytes[1] >> 6) & 0x1;
and_result = cpu.r.a & argument;
}
if(and_result===0) {
cpu.p.z = 1;
} else {
cpu.p.z = 0;
}
}
};
var COP = {
bytes_required:function() {
return 2;