Title here
Summary here
Command Line Flags in Assembly Language
section .data
word db "foo", 0
numb dd 42
fork db 0
svar db "bar", 0
usage db "Usage: program [-word=string] [-numb=int] [-fork] [-svar=string]", 10, 0
section .bss
argc resd 1
argv resq 1
section .text
global _start
_start:
; Get command line arguments
pop dword [argc]
mov [argv], esp
; Parse command line arguments
mov ecx, [argc]
mov esi, [argv]
call parse_args
; Print results
call print_results
; Exit program
mov eax, 60
xor edi, edi
syscall
parse_args:
; Loop through arguments
.loop:
lodsd
test eax, eax
jz .done
; Check for flags
cmp byte [eax], '-'
jne .next
inc eax
cmp dword [eax], 'word'
je .set_word
cmp dword [eax], 'numb'
je .set_numb
cmp dword [eax], 'fork'
je .set_fork
cmp dword [eax], 'svar'
je .set_svar
jmp .next
.set_word:
add eax, 5
mov [word], eax
jmp .next
.set_numb:
add eax, 5
call atoi
mov [numb], eax
jmp .next
.set_fork:
mov byte [fork], 1
jmp .next
.set_svar:
add eax, 5
mov [svar], eax
.next:
loop .loop
.done:
ret
print_results:
; Print word
mov eax, 1
mov edi, 1
mov esi, word
mov edx, 4
syscall
; Print numb
mov eax, [numb]
call print_int
; Print fork
movzx eax, byte [fork]
call print_int
; Print svar
mov eax, 1
mov edi, 1
mov esi, svar
mov edx, 4
syscall
ret
; Helper functions (not implemented for brevity)
atoi:
; Convert ASCII to integer
ret
print_int:
; Print integer to stdout
retThis Assembly Language code provides a basic implementation of command-line flag parsing, similar to the original Go example. Here’s an explanation of the code:
We define our data in the
.datasection, including default values for our flags.The
.bsssection is used for uninitialized data, where we store the argument count and pointer.In the
_startfunction (the entry point for Assembly programs), we retrieve the command-line arguments and call our parsing function.The
parse_argsfunction loops through the arguments, checking for flags and updating the corresponding variables when found.After parsing, we call
print_resultsto output the final values of our flags.Helper functions like
atoi(ASCII to integer) andprint_intare mentioned but not implemented for brevity.
To use this program, you would compile it into an executable and run it from the command line with various flags:
$ nasm -f elf64 command_line_flags.asm
$ ld -o command_line_flags command_line_flags.o
$ ./command_line_flags -word=hello -numb=100 -fork -svar=testNote that this is a simplified version and doesn’t include error handling or more advanced features of the original Go implementation. Assembly Language requires much more low-level management of memory and system calls, which makes the code more verbose and complex compared to higher-level languages.