rdos/kernel/main.asm

cpu 8086

; Memory layout (starting from top)
%define self    0xF000

; A single sector for deblocking
%define diskbuf (self-0x200)

%define stack   (diskbuf)

%define default_drive BYTE [0x4]

org self
jmp init

banner:
  db "RDOS 2019-09", 0x0A, 0x0D, '$', 0

init:
  mov sp, stack
  mov default_drive, 0x01

  mov dx, banner
  call print_string

  mov si, init_program
  call exec

  cli
.halt:
  hlt
  jmp .halt

init_program:
  db "HELLO.COM", 0

cpm_syscall:
  cmp cl, 0
  je init
  cmp cl, 1
  je console_input
  cmp cl, 2
  je console_output
  cmp cl, 9
  je print_string
  cmp cl, 10
  je read_buffer
  stc
  ret

%include "char.asm"

%include "exec.asm"
%include "fcb.asm"
%include "fcbparse.asm"
%include "drive.asm"
%include "log2.asm"
%include "dump.asm"