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SYS_EXIT equ 0x2000001 ;code
SYS_FORK equ 0x2000002 ;--
SYS_READ equ 0x2000003 ;fd, buf, len
SYS_WRITE equ 0x2000004 ;fd, buf, len
SYS_MMAP equ 0x20000C5 ;addr, len, prot, flags, fd, offset
global start, putc, putint, getc, _builtin_malloc
default rel
extern main
section .text
start:
call main
mov rdi, rax
mov eax, SYS_EXIT
syscall
jmp $
putc:
push rax
push rdi
push rsi
push rdx
push rcx
push r11
mov eax, SYS_WRITE
mov edi, 1
lea rsi, [rsp+56]
mov edx, edi
syscall
pop r11
pop rcx
pop rdx
pop rsi
pop rdi
pop rax
ret
putint:
push rdi
push rsi
push rax
push rbx
push rcx
push rdx
push r11
mov rax, [rsp+64]
mov ebx, 18
test rax, rax
jz .numzero
mov ecx, 10
.strlp:
xor edx, edx
div rcx
add dl, '0'
dec rbx
mov [rsp+rbx], dl
test rax, rax
jnz .strlp
jmp .strdone
.numzero:
dec rbx
mov byte [rsp+rbx], '0'
jmp .strdone
.strdone:
mov eax, SYS_WRITE
mov edi, 1
lea rsi, [rsp+rbx]
mov edx, 18
sub rdx, rbx
syscall
pop r11
pop rdx
pop rcx
pop rbx
pop rax
pop rsi
pop rdi
ret
getc:
push rdi
push rsi
push rdx
push rcx
push r11
mov eax, SYS_READ
xor edi, edi
mov rsi, rsp
mov edx, 1
syscall
cmp rax, 1
jne .fail
mov rax, [rsp]
.finish:
pop r11
pop rcx
pop rdx
pop rsi
pop rdi
ret
.fail:
mov rax, -1
jmp .finish
_builtin_malloc:
push rdi
push rsi
push rdx
push r8
push r9
push r10
push r11
push rcx
xor edi, edi
mov rsi, [rsp+72]
mov edx, 0x03
mov r10d, 0x1001
mov r8d, -1
xor r9d, r9d
mov eax, SYS_MMAP
syscall
pop rcx
pop r11
pop r10
pop r9
pop r8
pop rdx
pop rsi
pop rdi
ret
section .data
db 0 ; for dyld
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