lib/libstand/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  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  *
  33  *      @(#)quad.h      8.1 (Berkeley) 6/4/93
  34  * $FreeBSD$
  35  */
  36
  37 /*
  38  * Quad arithmetic.
  39  *
  40  * This library makes the following assumptions:
  41  *
  42  *  - The type long long (aka quad_t) exists.
  43  *
  44  *  - A quad variable is exactly twice as long as `long'.
  45  *
  46  *  - The machine's arithmetic is two's complement.
  47  *
  48  * This library can provide 128-bit arithmetic on a machine with 128-bit
  49  * quads and 64-bit longs, for instance, or 96-bit arithmetic on machines
  50  * with 48-bit longs.
  51  */
  52
  53 #include <sys/cdefs.h>
  54 #include <sys/types.h>
  55 #include <limits.h>
  56
  57 _Static_assert(sizeof(quad_t) == sizeof(int) * 2,
  58         "Bitwise function in libstand are broken on this architecture\n");
  59
  60 /*
  61  * Depending on the desired operation, we view a `long long' (aka quad_t) in
  62  * one or more of the following formats.
  63  */
  64 union uu {
  65         quad_t  q;              /* as a (signed) quad */
  66         quad_t  uq;             /* as an unsigned quad */
  67         int     sl[2];          /* as two signed ints */
  68         u_int   ul[2];          /* as two unsigned ints */
  69 };
  70
  71 /*
  72  * Define high and low longwords.
  73  */
  74 #define H               _QUAD_HIGHWORD
  75 #define L               _QUAD_LOWWORD
  76
  77 /*
  78  * Total number of bits in a quad_t and in the pieces that make it up.
  79  * These are used for shifting, and also below for halfword extraction
  80  * and assembly.
  81  */
  82 #define QUAD_BITS       (sizeof(quad_t) * CHAR_BIT)
  83 #define HALF_BITS       (sizeof(int) * CHAR_BIT / 2)
  84
  85 /*
  86  * Extract high and low shortwords from longword, and move low shortword of
  87  * longword to upper half of long, i.e., produce the upper longword of
  88  * ((quad_t)(x) << (number_of_bits_in_long/2)).  (`x' must actually be u_long.)
  89  *
  90  * These are used in the multiply code, to split a longword into upper
  91  * and lower halves, and to reassemble a product as a quad_t, shifted left
  92  * (sizeof(long)*CHAR_BIT/2).
  93  */
  94 #define HHALF(x)        ((x) >> HALF_BITS)
  95 #define LHALF(x)        ((x) & ((1 << HALF_BITS) - 1))
  96 #define LHUP(x)         ((x) << HALF_BITS)
  97
  98 quad_t          __divdi3(quad_t a, quad_t b);
  99 quad_t          __moddi3(quad_t a, quad_t b);
 100 u_quad_t        __qdivrem(u_quad_t u, u_quad_t v, u_quad_t *rem);
 101 u_quad_t        __udivdi3(u_quad_t a, u_quad_t b);
 102 u_quad_t        __umoddi3(u_quad_t a, u_quad_t b);
 103
 104 /*
 105  * XXX
 106  * Compensate for gcc 1 vs gcc 2.  Gcc 1 defines ?sh?di3's second argument
 107  * as u_quad_t, while gcc 2 correctly uses int.  Unfortunately, we still use
 108  * both compilers.
 109  */
 110 #if __GNUC__ >= 2
 111 typedef unsigned int    qshift_t;
 112 #else
 113 typedef u_quad_t        qshift_t;
 114 #endif