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65816.js
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added ASL and all of the addressing modes for it

This commit is contained in:
Preston Skupinski 2011-05-08 15:02:50 -04:00
parent 937dfdb7d8
commit b1c6249169
1 changed files with 122 additions and 1 deletions
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123
cpu.js
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@ -113,7 +113,10 @@ function CPU_65816() {
0x55 : EOR_direct_page_indexed_x,
0x4a : LSR_accumulator, 0x4e : LSR_absolute,
0x46 : LSR_direct_page, 0x5e : LSR_absolute_indexed_x,
0x56 : LSR_direct_page_indexed_x };
0x56 : LSR_direct_page_indexed_x, 0x0a : ASL_accumulator,
0x0e : ASL_absolute, 0x06 : ASL_direct_page,
0x1e : ASL_absolute_indexed_x,
0x16 : ASL_direct_page_indexed_x };
/**
* Take a raw hex string representing the program and execute it.
@ -192,6 +195,124 @@ var MMU = {
}
};
var ASL_accumulator = {
bytes_required:function() {
return 1;
},
execute:function(cpu) {
if(cpu.p.m) {
cpu.p.c = cpu.r.a >> 7;
cpu.r.a = cpu.r.a << 1;
cpu.r.a &= 0xff;
cpu.p.n = cpu.r.a >> 7;
} else {
cpu.p.c = cpu.r.a >> 15;
cpu.r.a = cpu.r.a << 1;
cpu.r.a &= 0xffff;
cpu.p.n = cpu.r.a >> 15;
}
if(cpu.r.a===0) {
cpu.p.z = 1;
} else {
cpu.p.z = 0;
}
}
};
var ASL_absolute = {
bytes_required:function() {
return 3;
},
execute:function(cpu, bytes) {
var location = (bytes[1]<<8)|bytes[0];
var shiftee;
if(cpu.p.m) {
shiftee = cpu.mmu.read_byte(location);
cpu.p.c = shiftee >> 7;
shiftee = shiftee << 1;
shiftee &= 0xff;
cpu.p.n = shiftee >> 7;
cpu.mmu.store_byte(location, shiftee);
} else {
var low_byte = cpu.mmu.read_byte(location);
var high_byte = cpu.mmu.read_byte(location+1);
shiftee = (high_byte<<8)|low_byte;
cpu.p.c = shiftee >> 15;
shiftee = shiftee << 1;
shiftee &= 0xffff;
cpu.p.n = shiftee >> 15;
low_byte = shiftee & 0x00ff;
high_byte = shiftee >> 8;
cpu.mmu.store_byte(location, low_byte);
cpu.mmu.store_byte(location+1, high_byte);
}
if(shiftee===0) {
cpu.p.z = 1;
} else {
cpu.p.z = 0;
}
}
};
var ASL_direct_page = {
bytes_required:function() {
return 2;
},
execute:function(cpu,bytes) {
var location = bytes[0]+cpu.r.d;
var shiftee;
if(cpu.p.m) {
shiftee = cpu.mmu.read_byte(location);
cpu.p.c = shiftee >> 7;
shiftee = shiftee << 1;
shiftee &= 0xff;
cpu.p.n = shiftee >> 7;
cpu.mmu.store_byte(location, shiftee);
} else {
var low_byte = cpu.mmu.read_byte(location);
var high_byte = cpu.mmu.read_byte(location+1);
shiftee = (high_byte<<8)|low_byte;
cpu.p.c = shiftee >> 15;
shiftee = shiftee << 1;
shiftee &= 0xffff;
cpu.p.n = shiftee >> 15;
low_byte = shiftee & 0x00ff;
high_byte = shiftee >> 8;
cpu.mmu.store_byte(location, low_byte);
cpu.mmu.store_byte(location+1, high_byte);
}
if(shiftee===0) {
cpu.p.z = 1;
} else {
cpu.p.z = 0;
}
}
};
var ASL_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;
ASL_absolute.execute(cpu, [location_low_byte, location_high_byte]);
}
};
var ASL_direct_page_indexed_x = {
bytes_required:function() {
return 2;
},
execute:function(cpu, bytes) {
ASL_direct_page.execute(cpu, [bytes[0]+cpu.r.x]);
}
};
var LSR_accumulator = {
bytes_required:function(cpu) {
return 1;