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65816.js
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added JSL and RTL

This commit is contained in:
Preston Skupinski 2011-05-09 14:43:47 -04:00
parent 3bbb03143b
commit 02835299a7
1 changed files with 29 additions and 1 deletions
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cpu.js
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@ -127,7 +127,7 @@ function CPU_65816() {
0xda : PHX, 0xfa : PLX, 0x08 : PHP, 0x28 : PLP,
0xf4 : PEA, 0xd4 : PEI, 0x8b : PHB, 0xab : PLB,
0x4b : PHK, 0x0b : PHD, 0x2b : PLD, 0x62 : PER,
0x20 : JSR, 0x60 : RTS };
0x20 : JSR, 0x60 : RTS, 0x22 : JSL, 0x6b : RTL };
/**
* Take a raw hex string representing the program and execute it.
@ -206,6 +206,34 @@ var MMU = {
}
};
var JSL = {
bytes_required:function() {
return 4;
},
execute:function(cpu, bytes) {
var location = cpu.r.pc - 1;
var low_byte = location & 0x00ff;
var high_byte = location >> 8;
cpu.mmu.store_byte(cpu.r.s--, cpu.r.pbr);
cpu.mmu.store_byte(cpu.r.s--, high_byte);
cpu.mmu.store_byte(cpu.r.s--, low_byte);
cpu.r.pbr = bytes[2];
cpu.r.pc = (bytes[1]<<8)|bytes[0];
}
};
var RTL = {
bytes_required:function() {
return 1;
},
execute:function(cpu) {
var low_byte = cpu.mmu.read_byte(++cpu.r.s);
var high_byte = cpu.mmu.read_byte(++cpu.r.s);
cpu.r.pbr = cpu.mmu.read_byte(++cpu.r.s);
cpu.r.pc = ((high_byte<<8)|low_byte) + 1;
}
};
var JSR = {
bytes_required:function() {
return 3;