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jeremybenn |
/*
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* (c) Copyright 1986 HEWLETT-PACKARD COMPANY
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*
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* To anyone who acknowledges that this file is provided "AS IS"
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* without any express or implied warranty:
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* permission to use, copy, modify, and distribute this file
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* for any purpose is hereby granted without fee, provided that
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* the above copyright notice and this notice appears in all
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* copies, and that the name of Hewlett-Packard Company not be
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* used in advertising or publicity pertaining to distribution
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* of the software without specific, written prior permission.
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* Hewlett-Packard Company makes no representations about the
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* suitability of this software for any purpose.
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*/
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/* SPECTRUM_ID: @(#)memset.s 37.4 86/08/25 */
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/*
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* memset(s, c, n)
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*
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* Sets first n chars in memory area s to value of character c.
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* Returns s.
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*/
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#ifndef _NAMESPACE_CLEAN
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#define NOSECDEF /* prevent _memset from being defined as entry */
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#endif
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#include "DEFS.h"
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#define TO arg0
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#define FILLCHAR arg1
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#define COUNT arg2
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#define TMP r31
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ENTRY(memset)
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comb,<= COUNT,r0,msexit /* return if count not positive */
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copy TO,ret0 /* return value is start of copy */
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comibf,<,n 5,COUNT,msbyteloop /* be straightforward */
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dep FILLCHAR,23,8,FILLCHAR /* dup low byte */
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dep FILLCHAR,15,16,FILLCHAR /* into high bytes */
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add TO,COUNT,TMP /* TMP points just past fill area */
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stbys,m FILLCHAR,0(TO) /* fill out first word */
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/*
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* If we're pointing to high-order byte, no fill will happen,
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* but permissions will be checked. We don't want this (we
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* might be pointing at the beginning of a protected region),
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* so we branch around stbys if neither low bits are set.
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*/
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bb,<,n TMP,31,filend /* if low bit is set, stbys */
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bb,>=,n TMP,30,endfil /* if next lowest bit isn't set */
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/* (and lowest isn't, either) */
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/* do not stbys */
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filend:
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stbys,m,e FILLCHAR,0(TMP) /* fill out the last */
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endfil:
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addi 4, TO, TO
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sub TMP,TO,COUNT /* will now divide by 4 */
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comb,=,n COUNT,r0,msexit /* If count is zero ret. */
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extru,<> COUNT,31,4,r1
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b msquadloop
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depi 0,31,4,COUNT /* will now divide by 16 */
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mswordloop:
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addib,<> -4,r1,mswordloop
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stws,ma FILLCHAR,4(TO)
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comb,=,n COUNT,r0,msexit /* If count is zero ret. */
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msquadloop:
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stws,ma FILLCHAR,4(TO)
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stws,ma FILLCHAR,4(TO)
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stws,ma FILLCHAR,4(TO)
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addib,<> -16,COUNT,msquadloop
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stws,ma FILLCHAR,4(TO)
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b,n msexit
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msbyteloop:
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addib,<> -1,COUNT,msbyteloop
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stbs,ma FILLCHAR,1(TO)
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msexit:
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EXIT(memset)
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