memory-mapper.js

class MemoryMapper {
    constructor() {
        this.regions = [];
    }

    map(device, start, end, remap = true) {
        const region = {
            device,
            start,
            end,
            remap
        };

        this.regions.unshift(region);

        return () => {
            this.regions = this.regions.filter(r => r !== region);
        }
    }

    findRegion(address) {
        const region = this.regions.find(r => address >= r.start && address <= r.end);
        if(!region) {
            throw new Error(`No memory region found for address ${address}`);
        }
        return region;
    }

    getUint8(address) {
        const region = this.findRegion(address);
        const finalAddress = region.remap
            ? address - region.start
            : address;

        return region.device.getUint8(finalAddress);
    }

    setUint8(address, value) {
        const region = this.findRegion(address);
        const finalAddress = region.remap
            ? address - region.start
            : address;
        
        return region.device.setUint8(finalAddress, value);
    }

    getUint16(address) {
        const region = this.findRegion(address);
        const finalAddress = region.remap
            ? address - region.start
            : address;

        return region.device.getUint16(finalAddress);
    }

    setUint16(address, value) {
        const region = this.findRegion(address);

        const finalAddress = region.remap
            ? address - region.start
            : address;

        return region.device.setUint16(finalAddress, value);
    }
}

module.exports = MemoryMapper;