6502/65816.js
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added direct page indexed x, absolute indexed x and absolute indexed y addressing modes for CMP

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Preston Skupinski 2011-05-13 15:24:00 -04:00
parent 7b821a0473
commit 38505fdc8b
1 changed files with 36 additions and 0 deletions
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36
cpu.js
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@ -97,6 +97,9 @@ function CPU_65816() {
0xe1 : SBC_direct_page_indexed_x,
0xc9 : CMP_const, 0xc5 : CMP_direct_page,
0xcd : CMP_absolute, 0xd2 : CMP_direct_page_indirect,
0xd5 : CMP_direct_page_indexed_x,
0xdd : CMP_absolute_indexed_x,
0xd9 : CMP_absolute_indexed_y,
0xd1 : CMP_direct_page_indirect_indexed_y,
0xe0 : CPX_const,
0xec : CPX_absolute, 0xe4 : CPX_direct_page,
@ -1686,6 +1689,15 @@ var CMP_direct_page = {
}
};
var CMP_direct_page_indexed_x = {
bytes_required:function() {
return 2;
},
execute:function(cpu, bytes) {
CMP_direct_page.execute(cpu, [bytes[0]+cpu.r.x]);
}
};
var CMP_direct_page_indirect = {
bytes_required:function() {
return 2;
@ -1740,6 +1752,30 @@ var CMP_absolute = {
}
};
var CMP_absolute_indexed_x = {
bytes_required:function() {
return 3;
},
execute:function(cpu, bytes) {
var location = ((bytes[1]<<8)|bytes[0])+cpu.r.x;
var location_high_byte = location >> 8;
var location_low_byte = location & 0x00ff;
CMP_absolute.execute(cpu, [location_low_byte, location_high_byte]);
}
};
var CMP_absolute_indexed_y = {
bytes_required:function() {
return 3;
},
execute:function(cpu, bytes) {
var location = ((bytes[1]<<8)|bytes[0])+cpu.r.y;
var location_high_byte = location >> 8;
var location_low_byte = location & 0x00ff;
CMP_absolute.execute(cpu, [location_low_byte, location_high_byte]);
}
};
var SBC_const = {
bytes_required:function(cpu) {
if(cpu.p.e|cpu.p.m) {