ksim65/src/main/kotlin/razorvine/ksim65/components/Component.kt

package razorvine.ksim65.components

import razorvine.ksim65.Bus

typealias UByte = Short
typealias Address = Int


/**
 * Base class for any component connected to the system bus.
 */
abstract class BusComponent {
    lateinit var bus: Bus

    /**
     * One clock cycle on the bus
     */
    abstract fun clock()

    /**
     * Reset all devices on the bus
     */
    abstract fun reset()
}

/**
 * Base class for components that have registers mapped into the cpu's address space.
 * Most I/O components fall into this category.
 */
abstract class MemMappedComponent(val startAddress: Address, val endAddress: Address) : BusComponent() {
    abstract operator fun get(offset: Int): UByte
    abstract operator fun set(offset: Int, data: UByte)

    init {
        require(endAddress >= startAddress)
        require(startAddress >= 0 && endAddress <= 0xffff) { "can only have 16-bit address space" }
    }

    fun hexDump(from: Address, to: Address, charmapper: ((Short) -> Char)? = null) {
        (from..to).chunked(16).forEach {
            print("\$${it.first().toString(16).padStart(4, '0')}  ")
            val bytes = it.map { address -> get(address - startAddress) }
            bytes.forEach { byte ->
                print(byte.toString(16).padStart(2, '0')+" ")
            }
            print("  ")
            val chars = if (charmapper != null) bytes.map { b -> charmapper(b) }
            else bytes.map { b -> if (b in 32..255) b.toInt().toChar() else '.' }
            println(chars.joinToString(""))
        }
    }
}

/**
 * Base class for components that actually contain memory (RAM or ROM chips).
 */
abstract class MemoryComponent(startAddress: Address, endAddress: Address) : MemMappedComponent(startAddress, endAddress) {

    abstract val data: Array<UByte>

    init {
        require(startAddress and 0xff == 0 && endAddress and 0xff == 0xff) { "address range must span complete page(s)" }
    }

    fun getBlock(start: Int, length: Int): Array<UByte> = data.copyOfRange(start, start+length)
}