cksum.s,v

来自「TCP-IP红宝书源代码」· S,V 代码 · 共 301 行

head	1.6;
access;
symbols;
locks
	dls:1.6; strict;
comment	@# @;


1.6
date	97.09.21.19.27.59;	author dls;	state Dist;
branches;
next	1.5;

1.5
date	94.08.12.05.36.46;	author dls;	state Works;
branches;
next	1.4;

1.4
date	94.08.11.06.09.52;	author dls;	state Works;
branches;
next	1.3;

1.3
date	94.08.11.00.16.29;	author dls;	state Works;
branches;
next	1.2;

1.2
date	94.08.11.00.07.19;	author dls;	state New;
branches;
next	1.1;

1.1
date	94.08.10.19.29.32;	author dls;	state DLS;
branches;
next	;


desc
@@


1.6
log
@pre-3e code
@
text
@	.text
	.align 2
	.globl	_cksum
_cksum:
	pushl	%ebp
	movl	%esp,%ebp

	movl	8(%ebp),%edx
	movl	12(%ebp),%ecx
	xorl	%eax,%eax		/* clear sum	*/
	testl	%ecx,%ecx		
	jle	L4
	sarl	$6,%ecx
	je	L5
L7:
	clc
	addl	(%edx),%eax
	adcl	4(%edx),%eax
	adcl	8(%edx),%eax
	adcl	12(%edx),%eax
	adcl	16(%edx),%eax
	adcl	20(%edx),%eax
	adcl	24(%edx),%eax
	adcl	28(%edx),%eax
	adcl	32(%edx),%eax
	adcl	36(%edx),%eax
	adcl	40(%edx),%eax
	adcl	44(%edx),%eax
	adcl	48(%edx),%eax
	adcl	52(%edx),%eax
	adcl	56(%edx),%eax
	adcl	60(%edx),%eax
	adcl	$0,%eax
	addl	$64,%edx
	decl	%ecx
	ja	L7
L5:
	movl	12(%ebp),%ecx
	andl	$0x3f,%ecx
	sarl	$2,%ecx	
	jle	L4
L3:
	clc
	addl	(%edx),%eax
	adcl	$0,%eax
	addl	$4,%edx
	decl	%ecx
	ja	L3
L4:

	movl	12(%ebp),%ecx
	andl	$2,%ecx
	jz	L1
	movzwl	(%edx),%ecx
	addl	%ecx,%eax
	addl	$2,%edx
L1:
	movl	12(%ebp),%ecx
	andl	$1,%ecx
	jz	L2
	xorl	%ecx,%ecx
	movb	(%edx),%cl
	addl	%ecx,%eax
L2:
	movl	%eax,%ecx
	shrl	$16,%eax
	andl	$0xffff,%eax
	andl	$0xffff,%ecx
	addl	%ecx,%eax
	movl	%eax,%ecx
	shrl	$16,%eax
	addl	%ecx,%eax

	notw	%ax
	movzwl	%ax,%eax
	leave
	ret
@


1.5
log
@*** empty log message ***
@
text
@@


1.4
log
@*** empty log message ***
@
text
@d10 30
a40 2
	xorl	%eax,%eax
	testl	%ecx,%ecx
@


1.3
log
@*** empty log message ***
@
text
@d1 1
a1 3
#NO_APP
gcc_compiled.:
.text
d3 1
a3 1
.globl _cksum
d5 9
a13 12
	pushl %ebp
	movl %esp,%ebp
	subl $12,%esp
	movl 12(%ebp),%eax
	movl 12(%ebp),%edx
	testl %eax,%eax
	jge L2
	incl %eax
L2:
	sarl $1,%eax
	movl %eax,%edx
	movl $0,-4(%ebp)
d15 6
a20 9
	cmpl $0,%edx
	jle L4
	movl 8(%ebp),%eax
	movzwl (%eax),%eax
	addl %eax,-4(%ebp)
	addl $2,8(%ebp)
L5:
	decl %edx
	jmp L3
d22 7
a28 24
	movl 12(%ebp),%eax
	andl $1,%eax
	testl %eax,%eax
	je L6
	movl 8(%ebp),%eax
	movzbw (%eax),%cx
	movw %cx,-8(%ebp)
	movzwl -8(%ebp),%eax
	addl %eax,-4(%ebp)
L6:
	movl -4(%ebp),%eax
	shrl $16,%eax
	movl -4(%ebp),%edx
	andl $65535,%edx
	movl %eax,%ecx
	addl %edx,%ecx
	movl %ecx,-4(%ebp)
	movl %ecx,%eax
	shrl $16,%eax
	addl %eax,-4(%ebp)
	movw -4(%ebp),%ax
	notw %ax
	movzwl %ax,%eax
	jmp L1
d30 18
@


1.2
log
@*** empty log message ***
@
text
@d17 1
a17 1
	movl %eax,-12(%ebp)
d20 1
a20 1
	cmpl $0,-12(%ebp)
d27 1
a27 1
	decl -12(%ebp)
@


1.1
log
@Initial revision
@
text
@d1 3
a3 3
/* cksum.s - cksum */

	.text
d5 1
a5 7
	.globl	_cksum

/*------------------------------------------------------------------------
 * cksum - a fast internet checksummer
 *	cksum(buf, nbytes)
 *------------------------------------------------------------------------
 */
d7 12
a18 9
	pushl	%ebp
	movl	%esp,%ebp

	movl	8(%ebp),%ebx
	movl	12(%ebp),%ecx
	sarl	$2,%ecx			/* count in longs	*/
	xorl	%eax,%eax		/* sum = 0		*/
	testl	%ecx,%ecx
	jle	L4
d20 9
a28 6
	clc
	addl	(%ebx),%eax
	adcl	$0,%eax
	addl	$4,%ebx
	decl	%ecx
	ja	L3
d30 24
a53 7

	movl	12(%ebp),%ecx
	andl	$2,%ecx
	jz	L1
	movzwl	(%ebx),%edx
	addl	%edx,%eax
	addl	$2,%ebx
a54 18
	movl	12(%ebp),%ecx
	andl	$1,%ecx
	jz	L2
	xorl	%ecx,%ecx
	movb	(%ebx),%cl
	addl	%ecx,%eax
L2:
	movl	%eax,%ecx
	shrl	$16,%eax
	andl	$0xffff,%eax
	andl	$0xffff,%ecx
	addl	%ecx,%eax
	movl	%eax,%ecx
	shrl	$16,%eax
	addl	%ecx,%eax

	notw	%ax
	movzwl	%ax,%eax
@