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'use strict';
const { Op, AddrMode} = require('./enum.js');
class Core {
constructor(size) {
this.data = new Array(size);
// initialize core to all DAT 0, 0
for (let i=0; i<size; i++) {
this.data[i] = {
opcode: Op.DAT,
a: { value: 0, mode: AddrMode.Immediate },
b: { value: 0, mode: AddrMode.Immediate },
};
}
}
normalize(pc, value) {
const v = (pc + value) % this.data.length;
if (v < 0) {
return v + this.data.length;
} else {
return v;
}
}
getLocation(pc, address) {
switch(address.mode) {
case AddrMode.Immediate:
throw "Cannot get location from immediate-mode address";
case AddrMode.Direct:
return this.normalize(pc, address.value);
case AddrMode.Indirect: {
let loc = this.normalize(pc, address.value);
let b = this.data[loc].b.value;
return this.normalize(pc, b);
}
case AddrMode.Predecrement: {
let loc = this.normalize(pc, address.value);
this.data[loc].b.value -= 1;
let b = this.data[loc].b.value;
return this.normalize(pc, b);
}
default:
throw `Invalid addressing mode "${address.mode}"`;
}
}
getValue(pc, address) {
const index = this.getLocation(pc, address);
return this.data[index];
}
}
exports.Core = Core;
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