74 lines
1.9 KiB
C
74 lines
1.9 KiB
C
/*
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* Mach Operating System
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* Copyright (c) 1991,1990,1989 Carnegie Mellon University
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* All Rights Reserved.
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*
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* Permission to use, copy, modify and distribute this software and its
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* documentation is hereby granted, provided that both the copyright
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* notice and this permission notice appear in all copies of the
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* software, derivative works or modified versions, and any portions
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* thereof, and that both notices appear in supporting documentation.
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*
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* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
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* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
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* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
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*
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* Carnegie Mellon requests users of this software to return to
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*
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* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
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* School of Computer Science
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* Carnegie Mellon University
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* Pittsburgh PA 15213-3890
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*
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* any improvements or extensions that they make and grant Carnegie Mellon
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* the rights to redistribute these changes.
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*/
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/*
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* $Id: bzero.c,v 1.1 1993/10/07 00:20:43 cgd Exp $
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*/
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/*
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* Object:
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* bzero EXPORTED function
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*
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* Clear memory locations
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*
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* Optimize for aligned memory ops, if possible and simple.
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* Might need later recoding in assembly for better efficiency.
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*/
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void
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bzero(addr, bcount)
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register unsigned addr;
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register unsigned bcount;
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{
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register int i;
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if (bcount == 0) /* sanity */
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return;
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switch (addr & 3) {
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case 1:
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*((char *) addr++) = 0;
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if (--bcount == 0)
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return;
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case 2:
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*((char *) addr++) = 0;
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if (--bcount == 0)
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return;
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case 3:
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*((char *) addr++) = 0;
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if (--bcount == 0)
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return;
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default:
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break;
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}
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for (i = bcount >> 2; i; i--, addr += 4)
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*((int *) addr) = 0;
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switch (bcount & 3) {
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case 3: *((char*)addr++) = 0;
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case 2: *((char*)addr++) = 0;
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case 1: *((char*)addr++) = 0;
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default:break;
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}
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}
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