retroforth/vm/nga-c-no-libc/macos.s

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; ___ ___ _____ ___ ___ __ ___ ___ ___ ___
; | _ \ __|_ _| _ \/ _ \ / / | __| _ ___ ___| _ ) __| \
; | / _| | | | / (_) | / / | _| '_/ -_) -_) _ \__ \ |) |
; |_|_\___| |_| |_|_\\___/ /_/ |_||_| \___\___|___/___/___/
;
; This is the minimal startup + I/O functionality needed to run
; RETRO on a FreeBSD x86-64 system.
; =============================================================
bits 64
section .text
global _putchar
global _getchar
global _start
extern _main
global start
align 8
start:
_start:
call _main
jmp $
align 8
_putchar:
mov rax, rdi
mov [rel buf], eax
mov rax, 0x2000004; sys_write
mov rdi, 1 ; stdout
mov rsi, buf ; address
mov rdx, 1 ; 1 byte
syscall
ret
align 8
_getchar:
mov rax, 0x2000003; sys_read
mov rdi, 0 ; stdin
mov rsi, buf ; address
mov rdx, 1 ; 1 byte
syscall
mov rax, 0
mov eax, [rel buf]
ret
section .data
buf:
dd 0
dd 0
dd 0
dd 0