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Partial implementation of ADD and SUB (SUB is missing carry flag handling

This commit is contained in:
n loewen 2023-07-25 15:26:32 +01:00
parent 51581e6879
commit dfd9edf879
1 changed files with 56 additions and 6 deletions
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62
simulator-sketch.js
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@ -33,6 +33,28 @@ function CPU(mem) {
this.acc = this.memory[addr];
this.instructionPointer = this.instructionPointer += 1;
},
add_lit: (lit) => {
console.log("ADD lit");
if ( (this.acc + lit) > 15 ) { this.carryFlag = 1; }
this.acc = (this.acc + lit % 15);
this.instructionPointer = this.instructionPointer += 1;
},
add_addr: (addr) => {
console.log("ADD addr");
if ( (this.acc + this.memory[addr]) > 15 ) { this.carryFlag = 1; }
this.acc = (this.acc + this.memory[addr] % 15);
this.instructionPointer = this.instructionPointer += 1;
},
sub_lit: (lit) => { // TODO: carry flag
console.log("SUB lit");
this.acc = this.acc - lit;
this.instructionPointer = this.instructionPointer += 1;
},
sub_addr: (addr) => { // TODO: carry flag
console.log("SUB addr");
this.acc = this.acc - this.memory[addr];
this.instructionPointer = this.instructionPointer += 1;
},
};
log_debug_state = () => {
@ -71,6 +93,22 @@ function CPU(mem) {
case 4:
this.instructions.load_addr(arg);
break;
case 5:
this.instructions.add_lit(arg);
break;
case 6:
this.instructions.add_addr(arg);
break;
case 7:
this.instructions.sub_lit(arg);
break;
case 8:
this.instructions.sub_addr(arg);
break;
default:
console.error( `Invalid opcode: ${opcode} with argument ${arg}` );
@ -100,10 +138,6 @@ function CPU(mem) {
};
// UNIMPLEMENTED
let add_lit = function(lit) { return; }
let add_addr = function(addr) { return; }
let subtract_lit = function(lit) { return; }
let subtract_addr = function(addr) { return; }
let hop_lit = function(lit) { return; }
let hop_addr = function(addr) { return; }
let jump_lit = function(lit) { return; }
@ -119,13 +153,29 @@ let halt_and_catch_fire = [
[1, 0],
];
let basic_test = [
let test_lda_sto = [
[3, 8], // LDA lit
[1, 5], // STO lit
[4, 5], // LDA addr
[2, 6], // STO addr
[0, 0], // END
];
// let comp = new CPU(test_lda_sto);
// comp.run_program();
let comp = new CPU(basic_test);
let test_add_sub_nocarry = [
[5, 6], // ADD lit ... acc = 6
[7, 1], // SUB lit ... acc = 5
[1, 8], // STO lit ... mem[8] = 5
[6, 8], // ADD addr ... acc = 10
[8, 8], // SUB addr ... acc = 5
[0, 0], // END
]
let test_add_sub = [
[5, 26], // ADD lit
[0, 0], // END
]
let comp = new CPU(test_add_sub);
comp.run_program();