c-switch.s

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

				# start of the file
.include "defines.h"		# system call numbers
.include "c-switch.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 $116, -4(%ebp)
	pushl %eax
	popl %eax
	pushl -4(%ebp)
	popl %eax
	cmpl $1, %eax
	je S0CASElabel0
	cmpl $2, %eax
	je S0CASElabel1
	cmpl $116, %eax
	je S0CASElabel2
S0CASElabel0:
	leal -4(%ebp), %eax
	pushl %eax
	popl %eax
	push (%eax)
	incl (%eax)
	popl %eax
	jmp ENDSWITCHlabel0
S0CASElabel1:
	leal -4(%ebp), %eax
	pushl %eax
	pushl $2
	popl %ebx
	popl %eax
	addl %ebx, (%eax)
	pushl (%eax)
	popl %eax
	jmp ENDSWITCHlabel0
S0CASElabel2:
	movl $113, -4(%ebp)
	pushl %eax
	popl %eax
	jmp ENDSWITCHlabel0
ENDSWITCHlabel0:
	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		# pass the char
	call cshow
	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