lib/libc/quad/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: src/lib/libc/quad/quad.h,v 1.8 2007/01/09 00:28:03 imp Exp $
  35  * $DragonFly: src/lib/libc/quad/quad.h,v 1.3 2003/11/12 20:21:25 eirikn Exp $
  36  */
  37
  38 /*
  39  * Quad arithmetic.
  40  *
  41  * This library makes the following assumptions:
  42  *
  43  *  - The type long long (aka quad_t) exists.
  44  *
  45  *  - A quad variable is exactly twice as long as `long'.
  46  *
  47  *  - The machine's arithmetic is two's complement.
  48  *
  49  * This library can provide 128-bit arithmetic on a machine with 128-bit
  50  * quads and 64-bit longs, for instance, or 96-bit arithmetic on machines
  51  * with 48-bit longs.
  52  */
  53
  54 #include <sys/types.h>
  55 #include <limits.h>
  56
  57 /*
  58  * Depending on the desired operation, we view a `long long' (aka quad_t) in
  59  * one or more of the following formats.
  60  */
  61 union uu {
  62         quad_t  q;              /* as a (signed) quad */
  63         quad_t  uq;             /* as an unsigned quad */
  64         long    sl[2];          /* as two signed longs */
  65         u_long  ul[2];          /* as two unsigned longs */
  66 };
  67
  68 /*
  69  * Define high and low longwords.
  70  */
  71 #define H               _QUAD_HIGHWORD
  72 #define L               _QUAD_LOWWORD
  73
  74 /*
  75  * Total number of bits in a quad_t and in the pieces that make it up.
  76  * These are used for shifting, and also below for halfword extraction
  77  * and assembly.
  78  */
  79 #define QUAD_BITS       (sizeof(quad_t) * CHAR_BIT)
  80 #define LONG_BITS       (sizeof(long) * CHAR_BIT)
  81 #define HALF_BITS       (sizeof(long) * CHAR_BIT / 2)
  82
  83 /*
  84  * Extract high and low shortwords from longword, and move low shortword of
  85  * longword to upper half of long, i.e., produce the upper longword of
  86  * ((quad_t)(x) << (number_of_bits_in_long/2)).  (`x' must actually be u_long.)
  87  *
  88  * These are used in the multiply code, to split a longword into upper
  89  * and lower halves, and to reassemble a product as a quad_t, shifted left
  90  * (sizeof(long)*CHAR_BIT/2).
  91  */
  92 #define HHALF(x)        ((x) >> HALF_BITS)
  93 #define LHALF(x)        ((x) & ((1 << HALF_BITS) - 1))
  94 #define LHUP(x)         ((x) << HALF_BITS)
  95
  96 int             __cmpdi2(quad_t a, quad_t b);
  97 quad_t          __divdi3(quad_t a, quad_t b);
  98 quad_t          __moddi3(quad_t a, quad_t b);
  99 u_quad_t        __qdivrem(u_quad_t u, u_quad_t v, u_quad_t *rem);
 100 int             __ucmpdi2(u_quad_t a, u_quad_t b);
 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 typedef unsigned int    qshift_t;