c-test.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-test.literals"	# include the string literal file
	.global _start	
	.bss
	.align	4
_data:
	.skip		8	# global variables' size
.text
	.align	4
_start:
	pushl %ebp		# save the ebp address
	movl %esp, %ebp
	subl $16, %esp		# allocate space for local variables
	movl $97, _data+0
	pushl %eax
	popl %eax
	movl $1, -4(%ebp)
	pushl %eax
	popl %eax
	movl $0, -8(%ebp)
	pushl %eax
	popl %eax
	movl $0, -12(%ebp)
	pushl %eax
	popl %eax
	movl $0, -16(%ebp)
	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 _data+0,%eax		# get the integer value of the ID
	call ishow
	call newline
	movl $1, -4(%ebp)
	pushl %eax
	popl %eax
WHILElabel0:
	pushl $1
	popl %eax
	cmpl $0, %eax
	je ENDWHILElabel0
	leal -16(%ebp), %eax
	pushl %eax
	pushl -16(%ebp)
	pushl -4(%ebp)
				# arithmetic calculate
	popl %ebx
	addl %ebx, (%esp)
	popl %ebx
	popl %eax
	movl %ebx, (%eax)
	pushl (%eax)
	popl %eax
	pushl $100
	pushl -4(%ebp)
	popl %ebx
	popl %eax
	cmpl %ebx, %eax
	sete %al
	movzbl %al, %eax
	pushl %eax
	cmpl $0, (%esp)
	je ELSElabel0
	jmp ENDWHILElabel0
	jmp ENDIFlabel0
ELSElabel0:
	leal -4(%ebp), %eax
	pushl %eax
	pushl -4(%ebp)
	pushl $1
				# arithmetic calculate
	popl %ebx
	addl %ebx, (%esp)
	popl %ebx
	popl %eax
	movl %ebx, (%eax)
	pushl (%eax)
	popl %eax
ENDIFlabel0:
	jmp WHILElabel0
ENDWHILElabel0:
	movl $SYS_write, %eax	# load the write call number
	movl $STDOUT, %ebx		# get the output channel
	movl $literal1,%ecx		# get the literal string
	movl $len1,%edx		# string length
	int $0x80
	movl -16(%ebp),%eax		# get the integer value of the ID
	call ishow
	call newline
	leal -8(%ebp), %eax
	pushl %eax
	pushl -16(%ebp)
	pushl -4(%ebp)
				# arithmetic calculate
	popl %ebx
	popl %eax
	cltd
	idivl %ebx
	pushl %eax
	popl %ebx
	popl %eax
	movl %ebx, (%eax)
	pushl (%eax)
	popl %eax
	leal -8(%ebp), %eax
	pushl %eax
	pushl -12(%ebp)
	pushl -8(%ebp)
	call getMax		# call function to get result to return
	pop %edx		# release pushed arguments memory after call
	pop %edx		# release pushed arguments memory after call
	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 $literal2,%ecx		# get the literal string
	movl $len2,%edx		# string length
	int $0x80
	movl -8(%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
getMax:
	pushl %ebp		# save the ebp address
	movl %esp, %ebp
	subl $0, %esp		# allocate space for local variables
	pushl 8(%ebp)
	pushl 12(%ebp)
	popl %ebx
	popl %eax
	cmpl %ebx, %eax
	setg %al
	movzbl %al, %eax
	pushl %eax
	cmpl $0, (%esp)
	je ELSElabel1
	pushl 8(%ebp)
	popl %eax		# save the return value in eax
	movl %ebp, %esp
	popl %ebp		# restore the ebp address
	ret
	jmp ENDIFlabel1
ELSElabel1:
	pushl 12(%ebp)
	popl %eax		# save the return value in eax
	movl %ebp, %esp
	popl %ebp		# restore the ebp address
	ret
ENDIFlabel1: