a.c

int main(int argc, char *argv[]) {
  if (argc == 1) return 0x0F;
  if (argc == 2) return 0xFF;
  return 0x00;
}

a.s

	.file	"a.c"
	.text
	.globl	main
	.type	main, @function
main:
.LFB0:
	.cfi_startproc
	pushq	%rbp
	.cfi_def_cfa_offset 16
	.cfi_offset 6, -16
	movq	%rsp, %rbp
	.cfi_def_cfa_register 6
	movl	%edi, -4(%rbp)
	movq	%rsi, -16(%rbp)
	cmpl	$1, -4(%rbp)
	jne	.L2
	movl	$15, %eax
	jmp	.L3
.L2:
	cmpl	$2, -4(%rbp)
	jne	.L4
	movl	$255, %eax
	jmp	.L3
.L4:
	movl	$0, %eax
.L3:
	popq	%rbp
	.cfi_def_cfa 7, 8
	ret
	.cfi_endproc
.LFE0:
	.size	main, .-main
	.ident	"GCC: (GNU) 10.1.0"
	.section	.note.GNU-stack,"",@progbits

b.c

int main(int argc, char *argv[]) {
  if (argc == 1) return 0x0F;
  else if (argc == 2) return 0xFF;
  return 0x00;
}

b.s

	.file	"b.c"
	.text
	.globl	main
	.type	main, @function
main:
.LFB0:
	.cfi_startproc
	pushq	%rbp
	.cfi_def_cfa_offset 16
	.cfi_offset 6, -16
	movq	%rsp, %rbp
	.cfi_def_cfa_register 6
	movl	%edi, -4(%rbp)
	movq	%rsi, -16(%rbp)
	cmpl	$1, -4(%rbp)
	jne	.L2
	movl	$15, %eax
	jmp	.L3
.L2:
	cmpl	$2, -4(%rbp)
	jne	.L4
	movl	$255, %eax
	jmp	.L3
.L4:
	movl	$0, %eax
.L3:
	popq	%rbp
	.cfi_def_cfa 7, 8
	ret
	.cfi_endproc
.LFE0:
	.size	main, .-main
	.ident	"GCC: (GNU) 10.1.0"
	.section	.note.GNU-stack,"",@progbits