sys/libkern/quad.h

   1 /*-
   2  * Copyright (c) 1992, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * This software was developed by the Computer Systems Engineering group
   6  * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
   7  * contributed to Berkeley.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  * 3. All advertising materials mentioning features or use of this software
  18  *    must display the following acknowledgement:
  19  *      This product includes software developed by the University of
  20  *      California, Berkeley and its contributors.
  21  * 4. Neither the name of the University nor the names of its contributors
  22  *    may be used to endorse or promote products derived from this software
  23  *    without specific prior written permission.
  24  *
  25  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  26  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  27  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  28  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  29  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  30  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  31  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  32  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  33  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  34  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  35  * SUCH DAMAGE.
  36  *
  37  *      @(#)quad.h      8.1 (Berkeley) 6/4/93
  38  * $FreeBSD: src/sys/libkern/quad.h,v 1.9 1999/08/28 00:46:36 peter Exp $
  39  * $DragonFly: src/sys/libkern/quad.h,v 1.5 2003/11/09 05:15:32 dillon Exp $
  40  */
  41
  42 /*
  43  * Quad arithmetic.
  44  *
  45  * This library makes the following assumptions:
  46  *
  47  *  - The type long long (aka quad_t) exists.
  48  *
  49  *  - A quad variable is exactly twice as long as `long'.
  50  *
  51  *  - The machine's arithmetic is two's complement.
  52  *
  53  * This library can provide 128-bit arithmetic on a machine with 128-bit
  54  * quads and 64-bit longs, for instance, or 96-bit arithmetic on machines
  55  * with 48-bit longs.
  56  */
  57
  58 #include <sys/cdefs.h>
  59 #include <sys/types.h>
  60 #include <machine/endian.h>
  61 #include <machine/limits.h>
  62
  63 /*
  64  * Depending on the desired operation, we view a `long long' (aka quad_t) in
  65  * one or more of the following formats.
  66  */
  67 union uu {
  68         quad_t  q;              /* as a (signed) quad */
  69         quad_t  uq;             /* as an unsigned quad */
  70         long    sl[2];          /* as two signed longs */
  71         u_long  ul[2];          /* as two unsigned longs */
  72 };
  73
  74 /*
  75  * Define high and low longwords.
  76  */
  77 #define H               _QUAD_HIGHWORD
  78 #define L               _QUAD_LOWWORD
  79
  80 /*
  81  * Total number of bits in a quad_t and in the pieces that make it up.
  82  * These are used for shifting, and also below for halfword extraction
  83  * and assembly.
  84  */
  85 #define QUAD_BITS       (sizeof(quad_t) * CHAR_BIT)
  86 #define LONG_BITS       (sizeof(long) * CHAR_BIT)
  87 #define HALF_BITS       (sizeof(long) * CHAR_BIT / 2)
  88
  89 /*
  90  * Extract high and low shortwords from longword, and move low shortword of
  91  * longword to upper half of long, i.e., produce the upper longword of
  92  * ((quad_t)(x) << (number_of_bits_in_long/2)).  (`x' must actually be u_long.)
  93  *
  94  * These are used in the multiply code, to split a longword into upper
  95  * and lower halves, and to reassemble a product as a quad_t, shifted left
  96  * (sizeof(long)*CHAR_BIT/2).
  97  */
  98 #define HHALF(x)        ((x) >> HALF_BITS)
  99 #define LHALF(x)        ((x) & ((1 << HALF_BITS) - 1))
 100 #define LHUP(x)         ((x) << HALF_BITS)
 101
 102 quad_t          __divdi3 (quad_t a, quad_t b);
 103 quad_t          __moddi3 (quad_t a, quad_t b);
 104 u_quad_t        __qdivrem (u_quad_t u, u_quad_t v, u_quad_t *rem);
 105 u_quad_t        __udivdi3 (u_quad_t a, u_quad_t b);
 106 u_quad_t        __umoddi3 (u_quad_t a, u_quad_t b);
 107 int             __ucmpdi2(u_quad_t a, u_quad_t b);
 108 int             __cmpdi2(quad_t a, quad_t b);
 109
 110
 111 /*
 112  * XXX
 113  * Compensate for gcc 1 vs gcc 2.  Gcc 1 defines ?sh?di3's second argument
 114  * as u_quad_t, while gcc 2 correctly uses int.  Unfortunately, we still use
 115  * both compilers.
 116  */
 117 #if __GNUC__ >= 2
 118 typedef unsigned int    qshift_t;
 119 #else
 120 typedef u_quad_t        qshift_t;
 121 #endif