5182dcbec2
(on an i486, 10 cycles (+ cache misses) instead of 15). The change should be a no-op if the compiler is any good. The best possible i*86 code for the same algorithm is only 1 more cycle faster on i486's so I don't want to bother implementing an assembler version. scanc() is a bottleneck for OPOST processing. It is naturally about 4 times as slow as bcopy() on 32-bit systems.
61 lines
2.3 KiB
C
61 lines
2.3 KiB
C
/*-
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* Copyright (c) 1992, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)scanc.c 8.1 (Berkeley) 6/10/93
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*
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* $Id: scanc.c,v 1.3 1995/03/17 06:15:39 phk Exp $
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*/
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#include <sys/libkern.h>
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int
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scanc(size, cp, table, mask0)
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u_int size;
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register u_char *cp, table[];
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int mask0;
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{
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register u_char *end;
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register u_char mask;
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mask = mask0;
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for (end = &cp[size]; cp < end; ++cp) {
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/*
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* gcc-2.6.3 generates poor (un)sign extension code on i386's.
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* The cast to volatile should have no effect, but in fact it
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* improves the code on i386's.
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*/
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if (table[*(volatile u_char *)cp] & mask)
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break;
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}
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return (end - cp);
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}
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