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pvcopy.S revision 1.2 
      1 /*	$NetBSD: pvcopy.S,v 1.2 2008/04/28 20:23:25 martin Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2003 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by David Laight.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 #include <machine/asm.h>
     33 
     34 /*
     35  * Routines to copy to/from absolute virtual addresses.
     36  * Needed because the boot code runs with %ds having a 64k offset
     37  * whereas Unix runs with a zero offset.
     38  *
     39  * These routines are optimised for code space, not execution speed.
     40  */
     41 
     42 /*
     43  * pbzero(void *dst, int cnt)
     44  *	zero absolute virtual memory
     45  */
     46 ENTRY(pbzero)
     47 	.code32
     48 	push	%edi
     49 	push	%es
     50 	mov	12(%esp),%edi
     51 	mov	16(%esp),%ecx
     52 
     53 	mov	$flatdataseg, %ax	/* selector with offset == 0 */
     54 	mov	%ax, %es
     55 	xor	%eax,%eax
     56 
     57 	cld
     58 	rep
     59 	stosb
     60 
     61 	pop	%es
     62 	pop	%edi
     63 	ret
     64 
     65 /*
     66  * vpbcopy(const void *src, void *dst, int cnt)
     67  *	Copy to absolute virtual address
     68  */
     69 ENTRY(vpbcopy)
     70 	.code32
     71 	push	%esi
     72 	push	%edi
     73 	push	%es
     74 	mov	16(%esp),%esi
     75 	mov	20(%esp),%edi
     76 	mov	24(%esp),%ecx
     77 
     78 	mov	$flatdataseg, %ax	/* selector with offset == 0 */
     79 	mov	%ax, %es
     80 	xor	%eax,%eax
     81 
     82 	cld
     83 	rep
     84 	movsb
     85 
     86 	popl	%es
     87 	popl	%edi
     88 	popl	%esi
     89 	ret
     90 
     91 /*
     92  * pvbcopy(const void *src, void *dst, int cnt)
     93  *	Copy from absolute virtual address
     94  */
     95 ENTRY(pvbcopy)
     96 	.code32
     97 	push	%esi
     98 	push	%edi
     99 	push	%ds
    100 	mov	16(%esp),%esi
    101 	mov	20(%esp),%edi
    102 	mov	24(%esp),%ecx
    103 
    104 	mov	$flatdataseg, %ax	/* selector with offset == 0 */
    105 	mov	%ax, %ds
    106 	xor	%eax,%eax
    107 
    108 	cld
    109 	rep
    110 	movsb
    111 
    112 	popl	%ds
    113 	popl	%edi
    114 	popl	%esi
    115 	ret
    116