section .data
MsgYes dw 'Yes'
MsgNo dw 'No'
section .text
global _start
_start:
call readNum
mov rsi, MsgYes
mov rbx , rax
inc rbx
shr rbx,2
cmp rax , 2
jz code
mov rcx,1
mov rsi, MsgNo
cmp rax , 1
jz code
lop:
inc rcx
push rax
div rcx
cmp rdx,0
je code
xor rdx,rdx
pop rax
cmp rbx,rcx
jne lop
mov rsi,MsgYes
code:
call printString
Exit:
mov rax, sys_exit
xor rdi, rdi
syscall
%ifndef SYS_EQUAL
%define SYS_EQUAL
sys_read equ 0
sys_write equ 1
sys_open equ 2
sys_close equ 3
sys_lseek equ 8
sys_create equ 85
sys_unlink equ 87
sys_mkdir equ 83
sys_makenewdir equ 0q777
sys_mmap equ 9
sys_mumap equ 11
sys_brk equ 12
sys_exit equ 60
stdin equ 0
stdout equ 1
stderr equ 3
PROT_NONE equ 0x0
PROT_READ equ 0x1
PROT_WRITE equ 0x2
MAP_PRIVATE equ 0x2
MAP_ANONYMOUS equ 0x20
;access mode
O_DIRECTORY equ 0q0200000
O_RDONLY equ 0q000000
O_WRONLY equ 0q000001
O_RDWR equ 0q000002
O_CREAT equ 0q000100
O_APPEND equ 0q002000
BEG_FILE_POS equ 0
CURR_POS equ 1
END_FILE_POS equ 2
; create permission mode
sys_IRUSR equ 0q400 ; user read permission
sys_IWUSR equ 0q200 ; user write permission
NL equ 0xA
Space equ 0x20
%endif
%ifndef NOWZARI_IN_OUT
%define NOWZARI_IN_OUT
;----------------------------------------------------
newLine:
push rax
mov rax, NL
call putc
pop rax
ret
;---------------------------------------------------------
putc:
push rcx
push rdx
push rsi
push rdi
push r11
push ax
mov rsi, rsp ; points to our char
mov rdx, 1 ; how many characters to print
mov rax, sys_write
mov rdi, stdout
syscall
pop ax
pop r11
pop rdi
pop rsi
pop rdx
pop rcx
ret
;---------------------------------------------------------
writeNum:
push rax
push rbx
push rcx
push rdx
sub rdx, rdx
mov rbx, 10
sub rcx, rcx
cmp rax, 0
jge wAgain
push rax
mov al, '-'
call putc
pop rax
neg rax
wAgain:
cmp rax, 9
jle cEnd
div rbx
push rdx
inc rcx
sub rdx, rdx
jmp wAgain
cEnd:
add al, 0x30
call putc
dec rcx
jl wEnd
pop rax
jmp cEnd
wEnd:
pop rdx
pop rcx
pop rbx
pop rax
ret
;---------------------------------------------------------
getc:
push rcx
push rdx
push rsi
push rdi
push r11
sub rsp, 1
mov rsi, rsp
mov rdx, 1
mov rax, sys_read
mov rdi, stdin
syscall
mov al, [rsi]
add rsp, 1
pop r11
pop rdi
pop rsi
pop rdx
pop rcx
ret
;---------------------------------------------------------
readNum:
push rcx
push rbx
push rdx
mov bl,0
mov rdx, 0
rAgain:
xor rax, rax
call getc
cmp al, '-'
jne sAgain
mov bl,1
jmp rAgain
sAgain:
cmp al, NL
je rEnd
cmp al, ' ' ;Space
je rEnd
sub rax, 0x30
imul rdx, 10
add rdx, rax
xor rax, rax
call getc
jmp sAgain
rEnd:
mov rax, rdx
cmp bl, 0
je sEnd
neg rax
sEnd:
pop rdx
pop rbx
pop rcx
ret
;-------------------------------------------
printString:
push rax
push rcx
push rsi
push rdx
push rdi
mov rdi, rsi
call GetStrlen
mov rax, sys_write
mov rdi, stdout
syscall
pop rdi
pop rdx
pop rsi
pop rcx
pop rax
ret
;-------------------------------------------
; rdi : zero terminated string start
GetStrlen:
push rbx
push rcx
push rax
xor rcx, rcx
not rcx
xor rax, rax
cld
repne scasb
not rcx
lea rdx, [rcx -1] ; length in rdx
pop rax
pop rcx
pop rbx
ret
;-------------------------------------------
%endif
Write, Run & Share Assembly code online using OneCompiler's Assembly online compiler for free. It's one of the robust, feature-rich online compilers for Assembly language. Getting started with the OneCompiler's Assembly compiler is simple and pretty fast. The editor shows sample boilerplate code when you choose language as Assembly and start coding.
Assembly language(asm) is a low-level programming language, where the language instructions will be more similar to machine code instructions.
Every assembler may have it's own assembly language designed for a specific computers or an operating system.
Assembly language requires less execution time and memory. It is more helful for direct hardware manipulation, real-time critical applications. It is used in device drivers, low-level embedded systems etc.
Assembly language usually consists of three sections,
Data section
To initialize variables and constants, buffer size these values doesn't change at runtime.
bss section
To declare variables
text section
_start specifies the starting of this section where the actually code is written.
There are various define directives to allocate space for variables for both initialized and uninitialized data.
variable-name define-directive initial-value
| Define Directive | Description | Allocated Space |
|---|---|---|
| DB | Define Byte | 1 byte |
| DW | Define Word | 2 bytes |
| DD | Define Doubleword | 4 bytes |
| DQ | Define Quadword | 8 bytes |
| DT | Define Ten Bytes | 10 bytes |
| Define Directive | Description |
|---|---|
| RESB | Reserve a Byte |
| RESW | Reserve a Word |
| RESD | Reserve a Doubleword |
| RESQ | Reserve a Quadword |
| REST | Reserve a Ten Bytes |
Constants can be defined using
CONSTANT_NAME EQU regular-exp or value
%assign constant_name value
%define constant_name value
Loops are used to iterate a set of statements for a specific number of times.
mov ECX,n
L1:
;<loop body>
loop L1
where n specifies the no of times loops should iterate.
Procedure is a sub-routine which contains set of statements. Usually procedures are written when multiple calls are required to same set of statements which increases re-usuability and modularity.
procedure_name:
;procedure body
ret