alcedo/kernel/kernel.nim

{.link: "boot.o".}
{.passL: "-ffreestanding -target i386 -nostdlib -T kernel/arch/i386/linker.ld".}
{.passC: "-ffreestanding -nostdlib --target=i386-pc-none-elf -march=i386".}

import tty, gdt, serial

type
  MemoryPointer{.unchecked.} = ptr array[0, char]

proc memcpy*(dest: ByteAddress, src: ByteAddress, count: int){.exportc.} =
  var destMem = cast[MemoryPointer](dest)
  var srcMem = cast[MemoryPointer](src)
  for i in 0..count-1:
    destMem[i] = srcMem[i]

proc memset*(dest: ByteAddress, value: char, count: int){.exportc.} =
  var destMem = cast[MemoryPointer](dest)
  for i in 0..count-1:
    destMem[i] = value

proc kernelMain() {.exportc: "kernel_main"}=
  serial.init()
  serial.write("Booting OS\L")
  gdt.gdtInstall()
  serial.write("GDT installed\L")
  terminalInitialize()
  terminalWrite("Hello World!\L")
  terminalWrite("MAX_INT:")
  terminalWrite(high(int))
  terminalWrite("\LMIN_INT:")
  terminalWrite(low(int32)+1)
  for i in 0..22:
    terminalWrite(i)
    terminalWrite('\L')