ram bank peripheral

tsvm_core/src/net/torvald/tsvm/peripheral/RamBank.kt

@@ -0,0 +1,73 @@
+package net.torvald.tsvm.peripheral
+
+import net.torvald.UnsafeHelper
+import net.torvald.terrarum.modulecomputers.virtualcomputer.tvd.toUint
+import net.torvald.tsvm.VM
+import java.io.File
+
+/**
+ * Created by minjaesong on 2022-07-20.
+ */
+open class RamBank(val vm: VM, bankCount: Int) : PeriBase {
+
+    val bankSize = 524288L
+
+    protected var banks = bankCount.coerceIn(2..256)
+        private set
+
+    init {
+        if (banks % 2 == 1) banks += 1
+    }
+
+    internal val mem = UnsafeHelper.allocate(bankSize * banks)
+
+    protected var map0 = 0
+    protected var map1 = 1
+
+    override fun peek(addr: Long): Byte {
+        return when (addr) {
+            in 0L until bankSize -> mem[bankSize * map0 + (addr % bankSize)]
+            in bankSize until 2 * bankSize -> mem[bankSize * map1 + (addr % bankSize)]
+            else -> throw IllegalArgumentException("Offset: $addr")
+        }
+    }
+
+    override fun poke(addr: Long, byte: Byte) {
+        when (addr) {
+            in 0L until bankSize -> mem[bankSize * map0 + (addr % bankSize)] = byte
+            in bankSize until 2 * bankSize -> mem[bankSize * map1 + (addr % bankSize)] = byte
+            else -> throw IllegalArgumentException("Offset: $addr")
+        }
+    }
+
+    override fun mmio_read(addr: Long): Byte {
+        return when (addr) {
+            0L -> map0.toByte()
+            1L -> map1.toByte()
+            else -> -1
+        }
+    }
+
+    override fun mmio_write(addr: Long, byte: Byte) {
+        when (addr) {
+            0L -> map0 = byte.toUint()
+            1L -> map1 = byte.toUint()
+        }
+    }
+
+    override fun dispose() {
+        mem.destroy()
+    }
+
+    override fun getVM() = vm
+
+    override val typestring = "RAMB"
+}
+
+open class RomBank(vm: VM, romfile: File, bankCount: Int) : RamBank(vm, bankCount) {
+    init {
+        val bytes = romfile.readBytes()
+        UnsafeHelper.memcpyRaw(bytes, 0, null, mem.ptr, bytes.size.toLong())
+    }
+    override val typestring = "ROMB"
+}