#############################################3
#% as -o argc.o argc.s && ld -o argc argc.o
#% ./argc 3 4 5
#4
#
#% as -o argc.o argc.s && ld -o argc argc.o -lc
#% ./argc 4 5 6
#zsh: no such file or directory: ./argc
#
#% gcc -m64 -o argc argc.s -nostdlib
#% ./argc 3 4 5
#4
#
#% gcc -m64 -o argc argc.s
#/tmp/ccfN2MUC.o: In function `_start':
#(.text+0x0): multiple definition of `_start'
#/usr/lib/gcc/x86_64-pc-linux-gnu/4.6.3/../../../../lib64/crt1.o:(.text+0x0): first defined here
#/usr/lib/gcc/x86_64-pc-linux-gnu/4.6.3/../../../../lib64/crt1.o: In function `_start':
#(.text+0x20): undefined reference to `main'
#collect2: ld returned 1 exit status
#
### Меняем `_start:' на `main:'
#
#% gcc -m64 -o argc argc.s
#% ./argc 3 4 5
#=���
#
### Код:

 .globl _start

  .data
newline: .ascii "\n"
 .set newline_len, . - newline

 .bss
argc: .space 8

 .text
_start:
 movq $1, %rax
 movq $1, %rdi
 movq (%rsp), %rbx
 movq %rbx, argc
 addq $48, argc
 movq $argc, %rsi
 movq $8, %rdx
 syscall

 movq $1, %rax
 movq $1, %rdi
 movq $newline, %rsi
 movq $newline_len, %rdx
 syscall

 movq $60, %rax
 xorq %rdi, %rdi
 syscall