zx-generation/src/interfaces/memory-interface.js

A high-fidelity ZX Spectrum emulator in JavaScript — fully generated by a large language model (LLM) to explore the boundaries of AI in systems programming.

/**
 * Memory Interface
 * Provides abstraction layer for memory access
 */
class MemoryInterface {
    constructor(memory) {
        this.memory = memory;
    }

    /**
     * Read a byte from memory
     */
    readByte(address) {
        return this.memory.read(address & 0xffff);
    }

    /**
     * Write a byte to memory
     */
    writeByte(address, value) {
        this.memory.write(address & 0xffff, value & 0xff);
    }

    /**
     * Read a 16-bit word from memory (little-endian)
     */
    readWord(address) {
        const addr = address & 0xffff;
        const low = this.memory.read(addr);
        const high = this.memory.read((addr + 1) & 0xffff);
        return low | (high << 8);
    }

    /**
     * Write a 16-bit word to memory (little-endian)
     */
    writeWord(address, value) {
        const addr = address & 0xffff;
        const val = value & 0xffff;
        this.memory.write(addr, val & 0xff);
        this.memory.write((addr + 1) & 0xffff, (val >> 8) & 0xff);
    }

    /**
     * Read byte and increment PC
     */
    fetchByte(registers) {
        const byte = this.readByte(registers.getPC());
        registers.incrementPC();
        return byte;
    }

    /**
     * Read word and increment PC by 2
     */
    fetchWord(registers) {
        const low = this.fetchByte(registers);
        const high = this.fetchByte(registers);
        return low | (high << 8);
    }

    /**
     * Push byte to stack
     */
    pushByte(registers, value) {
        const sp = (registers.get16('SP') - 1) & 0xffff;
        registers.set16('SP', sp);
        this.writeByte(sp, value);
    }

    /**
     * Pop byte from stack
     */
    popByte(registers) {
        const sp = registers.get16('SP');
        const value = this.readByte(sp);
        registers.set16('SP', (sp + 1) & 0xffff);
        return value;
    }

    /**
     * Push word to stack
     */
    pushWord(registers, value) {
        this.pushByte(registers, (value >> 8) & 0xff);
        this.pushByte(registers, value & 0xff);
    }

    /**
     * Pop word from stack
     */
    popWord(registers) {
        const low = this.popByte(registers);
        const high = this.popByte(registers);
        return low | (high << 8);
    }
}

export { MemoryInterface };