c-bit.s

来自「一个编译器的例子,基于c语言,在linux下开发 现在了简单的c语言例子」· S 代码 · 共 61 行

				# start of the file
.include "defines.h"		# system call numbers
.include "c-bit.literals"	# include the string literal file
	.global _start	
	.bss
	.align	4
_data:
.text
	.align	4
_start:
	pushl %ebp		# save the ebp address
	movl %esp, %ebp
	subl $4, %esp		# allocate space for local variables
	movl $8, -4(%ebp)
	pushl %eax
	popl %eax
	leal -4(%ebp), %eax
	pushl %eax
	pushl -4(%ebp)
	pushl $1
				# arithmetic calculate
	popl %ecx
	popl %eax
	sarl %cl, %eax
	pushl %eax
	popl %ebx
	popl %eax
	movl %ebx, (%eax)
	pushl (%eax)
	popl %eax
	leal -4(%ebp), %eax
	pushl %eax
	pushl -4(%ebp)
	pushl -4(%ebp)
				# arithmetic calculate
	popl %ebx
	popl %eax
	xorl %ebx, %eax
	pushl %eax
	popl %ebx
	popl %eax
	movl %ebx, (%eax)
	pushl (%eax)
	popl %eax
	movl $SYS_write, %eax	# load the write call number
	movl $STDOUT, %ebx		# get the output channel
	movl $literal0,%ecx		# get the literal string
	movl $len0,%edx		# string length
	int $0x80
	movl -4(%ebp),%eax		# get the integer value of the ID
	call ishow
	call newline
	pushl $0
	popl %eax		# save the return value in eax
	movl %ebp, %esp
	popl %ebp		# restore the ebp address
	movl $SYS_exit,%eax	# load the exit call number
	movl $0,%ebx		# load the exit code
	int $0x80		# and exit!
				# end of the file