retroforth/source/interfaces/native/old/obsd64.s
crc f7a0698486 source tree reorganizations
FossilOrigin-Name: 654eda2d23299be894f94e8b615e7432de6a3bd5dbb6f4caa454cc20e65a510b
2019-05-02 16:25:16 +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