usr/src/lib/libbc/libc/gen/common/_base_il.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License, Version 1.0 only
   6  * (the "License").  You may not use this file except in compliance
   7  * with the License.
   8  *
   9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
  10  * or http://www.opensolaris.org/os/licensing.
  11  * See the License for the specific language governing permissions
  12  * and limitations under the License.
  13  *
  14  * When distributing Covered Code, include this CDDL HEADER in each
  15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  16  * If applicable, add the following below this CDDL HEADER, with the
  17  * fields enclosed by brackets "[]" replaced with your own identifying
  18  * information: Portions Copyright [yyyy] [name of copyright owner]
  19  *
  20  * CDDL HEADER END
  21  */
  22 /*
  23  * Copyright 1988 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26
  27 #pragma ident   "%Z%%M% %I%     %E% SMI"
  28
  29 #include "base_conversion.h"
  30
  31 /*      The following should be coded as inline expansion templates.    */
  32
  33 /*
  34  * Fundamental utilities that multiply two shorts into a unsigned long, add
  35  * carry, compute quotient and remainder in underlying base, and return
  36  * quo<<16 | rem as  a unsigned long.
  37  */
  38
  39 /*
  40  * C compilers tend to generate bad code - forcing full unsigned long by
  41  * unsigned long multiplies when what is really wanted is the unsigned long
  42  * product of half-long operands. Similarly the quotient and remainder are
  43  * all half-long. So these functions should really be implemented by inline
  44  * expansion templates.
  45  */
  46
  47 /* p = x * y + c ; return p */
  48 unsigned long
  49 _umac(_BIG_FLOAT_DIGIT x, _BIG_FLOAT_DIGIT y, unsigned long c)
  50 {
  51         return (x * (unsigned long) y + c);
  52 }
  53
  54 /* p = x + c ; return (p/10000 << 16 | p%10000) */
  55 unsigned long
  56 _carry_in_b10000(_BIG_FLOAT_DIGIT x, long unsigned c)
  57 {
  58         unsigned long   p = x + c ;
  59
  60         return ((p / 10000) << 16) | (p % 10000);
  61 }
  62
  63 void
  64 _carry_propagate_two(unsigned long carry, _BIG_FLOAT_DIGIT *psignificand)
  65 {
  66         /*
  67          * Propagate carries in a base-2**16 significand.
  68          */
  69
  70         long unsigned   p;
  71         int             j;
  72
  73         j = 0;
  74         while (carry != 0) {
  75         p = _carry_in_b65536(psignificand[j],carry);
  76                 psignificand[j++] = (_BIG_FLOAT_DIGIT) (p & 0xffff);
  77                 carry = p >> 16;
  78         }
  79 }
  80
  81 void
  82 _carry_propagate_ten(unsigned long carry, _BIG_FLOAT_DIGIT *psignificand)
  83 {
  84         /*
  85          * Propagate carries in a base-10**4 significand.
  86          */
  87
  88         int             j;
  89         unsigned long p;
  90
  91         j = 0;
  92         while (carry != 0) {
  93         p = _carry_in_b10000(psignificand[j],carry);
  94                 psignificand[j++] = (_BIG_FLOAT_DIGIT) (p & 0xffff);
  95                 carry = p >> 16;
  96         }
  97 }