6502
/
65816.js
mirror of https://github.com/pskupinski/65816.js.git
1
0
Fork 0
Code Issues Projects Releases Wiki Activity

added CMP absolute and CPX/CPY immediate, direct page and absolute

This commit is contained in:
Preston Skupinski 2011-05-07 20:42:09 -04:00
parent cbe6896e8f
commit 645c3b6a5b
1 changed files with 161 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

162
cpu.js
View File

@ -85,7 +85,11 @@ function CPU_65816() {
0x7d : ADC_absolute_indexed_x,
0x79 : ADC_absolute_indexed_y,
0x75 : ADC_direct_page_indexed_x, 0xe9 : SBC_const,
0xc9 : CMP_const, 0xc5 : CMP_direct_page };
0xc9 : CMP_const, 0xc5 : CMP_direct_page,
0xcd : CMP_absolute, 0xe0 : CPX_const,
0xec : CPX_absolute, 0xe4 : CPX_direct_page,
0xc0 : CPY_const, 0xcc : CPY_absolute,
0xc4 : CPY_direct_page };
/**
* Take a raw hex string representing the program and execute it.
@ -164,6 +168,146 @@ var MMU = {
}
};
var CPX_const = {
bytes_required:function(cpu) {
if(cpu.p.x) {
return 2;
} else {
return 3;
}
},
execute:function(cpu, bytes) {
var result;
if(cpu.p.x) {
result = cpu.r.x - bytes[0];
if(result<0) {
cpu.p.c = 0;
result = 0x100 + result;
} else {
cpu.p.c = 1;
}
cpu.p.n = result >> 7;
} else {
result = cpu.r.x - ((bytes[1]<<8)|bytes[0]);
if(result<0) {
cpu.p.c = 0;
result = 0x10000 + result;
} else {
cpu.p.c = 1;
}
cpu.p.n = result >> 15;
}
if(result===0) {
cpu.p.z = 1;
} else {
cpu.p.z = 0;
}
}
};
var CPX_direct_page = {
bytes_required:function() {
return 2;
},
execute:function(cpu, bytes) {
var location = bytes[0] + cpu.r.d;
if(cpu.p.m) {
CPX_const.execute(cpu, cpu.mmu.read_byte(location));
} else {
var low_byte = cpu.mmu.read_byte(location);
var high_byte = cpu.mmu.read_byte(location+1);
CPX_const.execute(cpu, [low_byte, high_byte]);
}
}
};
var CPX_absolute = {
bytes_required:function() {
return 3;
},
execute:function(cpu, bytes) {
var location = (bytes[1]<<8)|bytes[0];
if(cpu.p.x) {
CPX_const.execute(cpu, [cpu.mmu.read_byte(location)]);
} else {
var low_byte = cpu.mmu.read_byte(location);
var high_byte = cpu.mmu.read_byte(location+1);
CPX_const.execute(cpu, [low_byte, high_byte]);
}
}
};
var CPY_const = {
bytes_required:function(cpu) {
if(cpu.p.x) {
return 2;
} else {
return 3;
}
},
execute:function(cpu, bytes) {
var result;
if(cpu.p.x) {
result = cpu.r.y - bytes[0];
if(result<0) {
cpu.p.c = 0;
result = 0x100 + result;
} else {
cpu.p.c = 1;
}
cpu.p.n = result >> 7;
} else {
result = cpu.r.y - ((bytes[1]<<8)|bytes[0]);
if(result<0) {
cpu.p.c = 0;
result = 0x10000 + result;
} else {
cpu.p.c = 1;
}
cpu.p.n = result >> 15;
}
if(result===0) {
cpu.p.z = 1;
} else {
cpu.p.z = 0;
}
}
};
var CPY_direct_page = {
bytes_required:function() {
return 2;
},
execute:function(cpu, bytes) {
var location = bytes[0] + cpu.r.d;
if(cpu.p.m) {
CPY_const.execute(cpu, cpu.mmu.read_byte(location));
} else {
var low_byte = cpu.mmu.read_byte(location);
var high_byte = cpu.mmu.read_byte(location+1);
CPY_const.execute(cpu, [low_byte, high_byte]);
}
}
};
var CPY_absolute = {
bytes_required:function() {
return 3;
},
execute:function(cpu, bytes) {
var location = (bytes[1]<<8)|bytes[0];
if(cpu.p.x) {
CPY_const.execute(cpu, [cpu.mmu.read_byte(location)]);
} else {
var low_byte = cpu.mmu.read_byte(location);
var high_byte = cpu.mmu.read_byte(location+1);
CPY_const.execute(cpu, [low_byte, high_byte]);
}
}
};
var CMP_const = {
bytes_required:function(cpu) {
if(cpu.p.m) {
@ -218,6 +362,22 @@ var CMP_direct_page = {
}
};
var CMP_absolute = {
bytes_required:function() {
return 3;
},
execute:function(cpu, bytes) {
var location = (bytes[1]<<8)|bytes[0];
if(cpu.p.m) {
CMP_const.execute(cpu, [cpu.mmu.read_byte(location)]);
} else {
var low_byte = cpu.mmu.read_byte(location);
var high_byte = cpu.mmu.read_byte(location+1);
CMP_const.execute(cpu, [low_byte, high_byte]);
}
}
};
var SBC_const = {
bytes_required:function(cpu) {
if(cpu.p.m) {