retroforth/interfaces/native/old/obsd64.s
crc 84c68ff9d6 retro/native: source tree cleanups
FossilOrigin-Name: be353986872e9d6592f18ab6a974ef6bcdf24a3113fa66ca0edeaf52286bd035
2019-02-21 17:21:48 +00:00

44 lines
884 B
ArmAsm

; This is the minimal startup + I/O functionality needed to run
; RETRO on an OpenBSD x86-64 system.
; =============================================================
bits 64
section .text
global putchar
global getchar
global _start
extern main
align 8
_start:
call main
jmp $
align 8
putchar:
mov rax, rdi
mov [buf], eax
mov rax, 4 ; sys_write
mov rdi, 1 ; stdout
mov rsi, buf ; address
mov rdx, 1 ; 1 byte
syscall
ret
align 8
getchar:
mov rax, 3 ; sys_read
mov rdi, 0 ; stdin
mov rsi, buf ; address
mov rdx, 1 ; 1 byte
syscall
mov rax, 0
mov eax, [buf]
ret
section .data
buf:
dd 0
dd 0
dd 0
dd 0