| 1 | /* $Id: softfloat.c,v 1.4 2009/07/29 12:32:34 ragge Exp $ */
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| 2 |
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| 3 | /*
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| 4 | * Copyright (c) 2008 Anders Magnusson. All rights reserved.
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| 5 | *
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| 6 | * Redistribution and use in source and binary forms, with or without
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| 7 | * modification, are permitted provided that the following conditions
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| 8 | * are met:
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| 9 | * 1. Redistributions of source code must retain the above copyright
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| 10 | * notice, this list of conditions and the following disclaimer.
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| 11 | * 2. Redistributions in binary form must reproduce the above copyright
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| 12 | * notice, this list of conditions and the following disclaimer in the
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| 13 | * documentation and/or other materials provided with the distribution.
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| 14 | * 3. The name of the author may not be used to endorse or promote products
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| 15 | * derived from this software without specific prior written permission
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| 16 | *
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| 17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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| 18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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| 19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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| 20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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| 21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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| 22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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| 23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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| 24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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| 25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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| 26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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| 27 | */
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| 28 |
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| 29 | #ifdef SOFTFLOAT
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| 30 |
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| 31 | #include "pass1.h"
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| 32 |
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| 33 |
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| 34 | /*
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| 35 | * Floating point emulation to be used when cross-compiling.
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| 36 | * Currently only supports F- and D-float, used in DEC machines.
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| 37 | * Should be trivial to add other emulations.
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| 38 | *
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| 39 | * XXX - assumes that:
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| 40 | * - long long is (at least) 64 bits
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| 41 | * - int is at least 32 bits.
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| 42 | * - short is 16 bits.
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| 43 | */
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| 44 |
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| 45 | #ifdef FDFLOAT
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| 46 |
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| 47 | /*
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| 48 | * Useful macros to manipulate the float.
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| 49 | */
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| 50 | #define DSIGN(w) (((w).fd1 >> 15) & 1)
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| 51 | #define DSIGNSET(w,s) ((w).fd1 = (s << 15) | ((w).fd1 & 077777))
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| 52 | #define DEXP(w) (((w).fd1 >> 7) & 0377)
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| 53 | #define DEXPSET(w,e) ((w).fd1 = (((e) & 0377) << 7) | ((w).fd1 & 0100177))
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| 54 | #define DMANTH(w) ((w).fd1 & 0177)
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| 55 | #define DMANTHSET(w,m) ((w).fd1 = ((m) & 0177) | ((w).fd1 & 0177600))
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| 56 |
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| 57 | typedef unsigned int lword;
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| 58 | typedef unsigned long long dword;
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| 59 |
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| 60 | #define MAXMANT 0x100000000000000LL
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| 61 |
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| 62 | /*
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| 63 | * Returns a zero dfloat.
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| 64 | */
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| 65 | static SF
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| 66 | nulldf(void)
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| 67 | {
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| 68 | SF rv;
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| 69 |
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| 70 | rv.fd1 = rv.fd2 = rv.fd3 = rv.fd4 = 0;
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| 71 | return rv;
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| 72 | }
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| 73 |
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| 74 | /*
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| 75 | * Convert a (u)longlong to dfloat.
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| 76 | * XXX - fails on too large (> 55 bits) numbers.
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| 77 | */
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| 78 | SF
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| 79 | soft_cast(CONSZ ll, TWORD t)
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| 80 | {
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| 81 | int i;
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| 82 | SF rv;
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| 83 |
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| 84 | rv = nulldf();
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| 85 | if (ll == 0)
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| 86 | return rv; /* fp is zero */
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| 87 | if (ll < 0)
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| 88 | DSIGNSET(rv,1), ll = -ll;
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| 89 | for (i = 0; ll > 0; i++, ll <<= 1)
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| 90 | ;
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| 91 | DEXPSET(rv, 192-i);
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| 92 | DMANTHSET(rv, ll >> 56);
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| 93 | rv.fd2 = ll >> 40;
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| 94 | rv.fd3 = ll >> 24;
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| 95 | rv.fd4 = ll >> 8;
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| 96 | return rv;
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| 97 | }
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| 98 |
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| 99 | /*
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| 100 | * multiply two dfloat. Use chop, not round.
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| 101 | */
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| 102 | SF
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| 103 | soft_mul(SF p1, SF p2)
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| 104 | {
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| 105 | SF rv;
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| 106 | lword a1[2], a2[2], res[4];
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| 107 | dword sum;
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| 108 |
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| 109 | res[0] = res[1] = res[2] = res[3] = 0;
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| 110 |
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| 111 | /* move mantissa into lwords */
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| 112 | a1[0] = p1.fd4 | (p1.fd3 << 16);
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| 113 | a1[1] = p1.fd2 | DMANTH(p1) << 16 | 0x800000;
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| 114 |
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| 115 | a2[0] = p2.fd4 | (p2.fd3 << 16);
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| 116 | a2[1] = p2.fd2 | DMANTH(p2) << 16 | 0x800000;
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| 117 |
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| 118 | #define MULONE(x,y,r) sum += (dword)a1[x] * (dword)a2[y]; sum += res[r]; \
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| 119 | res[r] = sum; sum >>= 32;
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| 120 |
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| 121 | sum = 0;
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| 122 | MULONE(0, 0, 0);
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| 123 | MULONE(1, 0, 1);
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| 124 | res[2] = sum;
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| 125 | sum = 0;
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| 126 | MULONE(0, 1, 1);
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| 127 | MULONE(1, 1, 2);
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| 128 | res[3] = sum;
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| 129 |
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| 130 | rv.fd1 = 0;
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| 131 | DSIGNSET(rv, DSIGN(p1) ^ DSIGN(p2));
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| 132 | DEXPSET(rv, DEXP(p1) + DEXP(p2) - 128);
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| 133 | if (res[3] & 0x8000) {
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| 134 | res[3] = (res[3] << 8) | (res[2] >> 24);
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| 135 | res[2] = (res[2] << 8) | (res[1] >> 24);
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| 136 | } else {
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| 137 | DEXPSET(rv, DEXP(rv) - 1);
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| 138 | res[3] = (res[3] << 9) | (res[2] >> 23);
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| 139 | res[2] = (res[2] << 9) | (res[1] >> 23);
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| 140 | }
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| 141 | DMANTHSET(rv, res[3] >> 16);
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| 142 | rv.fd2 = res[3];
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| 143 | rv.fd3 = res[2] >> 16;
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| 144 | rv.fd4 = res[2];
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| 145 | return rv;
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| 146 | }
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| 147 |
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| 148 | SF
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| 149 | soft_div(SF t, SF n)
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| 150 | {
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| 151 | SF rv;
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| 152 | dword T, N, K;
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| 153 | int c;
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| 154 |
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| 155 | #define SHL(x,b) ((dword)(x) << b)
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| 156 | T = SHL(1,55) | SHL(DMANTH(t), 48) |
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| 157 | SHL(t.fd2, 32) | SHL(t.fd3, 16) | t.fd4;
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| 158 | N = SHL(1,55) | SHL(DMANTH(n), 48) |
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| 159 | SHL(n.fd2, 32) | SHL(n.fd3, 16) | n.fd4;
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| 160 |
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| 161 | c = T > N;
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| 162 | for (K = 0; (K & 0x80000000000000ULL) == 0; ) {
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| 163 | if (T >= N) {
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| 164 | T -= N;
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| 165 | K |= 1;
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| 166 | }
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| 167 | T <<= 1;
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| 168 | K <<= 1;
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| 169 | }
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| 170 | rv.fd1 = 0;
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| 171 | DSIGNSET(rv, DSIGN(t) ^ DSIGN(n));
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| 172 | DEXPSET(rv, DEXP(t) - DEXP(n) + 128 + c);
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| 173 | DMANTHSET(rv, K >> 48);
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| 174 | rv.fd2 = K >> 32;
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| 175 | rv.fd3 = K >> 16;
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| 176 | rv.fd4 = K;
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| 177 | return rv;
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| 178 | }
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| 179 |
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| 180 | /*
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| 181 | * Negate a float number. Easy.
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| 182 | */
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| 183 | SF
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| 184 | soft_neg(SF sf)
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| 185 | {
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| 186 | int sign = DSIGN(sf) == 0;
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| 187 | DSIGNSET(sf, sign);
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| 188 | return sf;
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| 189 | }
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| 190 |
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| 191 | /*
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| 192 | * Return true if fp number is zero.
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| 193 | */
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| 194 | int
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| 195 | soft_isz(SF sf)
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| 196 | {
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| 197 | return (DEXP(sf) == 0);
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| 198 | }
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| 199 |
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| 200 | int
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| 201 | soft_cmp_eq(SF x1, SF x2)
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| 202 | {
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| 203 | cerror("soft_cmp_eq");
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| 204 | return 0;
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| 205 | }
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| 206 |
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| 207 | int
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| 208 | soft_cmp_ne(SF x1, SF x2)
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| 209 | {
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| 210 | cerror("soft_cmp_ne");
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| 211 | return 0;
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| 212 | }
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| 213 |
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| 214 | int
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| 215 | soft_cmp_le(SF x1, SF x2)
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| 216 | {
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| 217 | cerror("soft_cmp_le");
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| 218 | return 0;
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| 219 | }
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| 220 |
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| 221 | int
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| 222 | soft_cmp_lt(SF x1, SF x2)
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| 223 | {
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| 224 | cerror("soft_cmp_lt");
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| 225 | return 0;
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| 226 | }
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| 227 |
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| 228 | int
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| 229 | soft_cmp_ge(SF x1, SF x2)
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| 230 | {
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| 231 | cerror("soft_cmp_ge");
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| 232 | return 0;
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| 233 | }
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| 234 |
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| 235 | int
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| 236 | soft_cmp_gt(SF x1, SF x2)
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| 237 | {
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| 238 | cerror("soft_cmp_gt");
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| 239 | return 0;
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| 240 | }
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| 241 |
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| 242 | /*
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| 243 | * Convert a fp number to a CONSZ.
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| 244 | */
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| 245 | CONSZ
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| 246 | soft_val(SF sf)
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| 247 | {
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| 248 | CONSZ mant;
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| 249 | int exp = DEXP(sf) - 128;
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| 250 |
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| 251 | mant = SHL(1,55) | SHL(DMANTH(sf), 48) |
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| 252 | SHL(sf.fd2, 32) | SHL(sf.fd3, 16) | sf.fd4;
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| 253 |
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| 254 | while (exp < 0)
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| 255 | mant >>= 1, exp++;
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| 256 | while (exp > 0)
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| 257 | mant <<= 1, exp--;
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| 258 | return mant;
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| 259 | }
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| 260 |
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| 261 | SF
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| 262 | soft_plus(SF x1, SF x2)
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| 263 | {
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| 264 | cerror("soft_plus");
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| 265 | return x1;
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| 266 | }
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| 267 |
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| 268 | SF
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| 269 | soft_minus(SF x1, SF x2)
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| 270 | {
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| 271 | cerror("soft_minus");
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| 272 | return x1;
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| 273 | }
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| 274 |
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| 275 | /*
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| 276 | * Convert a hex constant to floating point number.
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| 277 | */
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| 278 | NODE *
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| 279 | fhexcon(char *s)
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| 280 | {
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| 281 | cerror("fhexcon");
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| 282 | return NULL;
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| 283 | }
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| 284 |
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| 285 | /*
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| 286 | * Convert a floating-point constant to D-float and store it in a NODE.
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| 287 | */
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| 288 | NODE *
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| 289 | floatcon(char *s)
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| 290 | {
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| 291 | NODE *p;
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| 292 | dword mant;
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| 293 | SF fl, flexp, exp5;
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| 294 | int exp, negexp, bexp;
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| 295 |
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| 296 | exp = 0;
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| 297 | mant = 0;
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| 298 | #define ADDTO(sum, val) sum = sum * 10 + val - '0'
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| 299 | for (; *s >= '0' && *s <= '9'; s++) {
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| 300 | if (mant<MAXMANT)
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| 301 | ADDTO(mant, *s);
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| 302 | else
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| 303 | exp++;
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| 304 | }
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| 305 | if (*s == '.') {
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| 306 | for (s++; *s >= '0' && *s <= '9'; s++) {
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| 307 | if (mant<MAXMANT) {
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| 308 | ADDTO(mant, *s);
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| 309 | exp--;
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| 310 | }
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| 311 | }
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| 312 | }
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| 313 |
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| 314 | if ((*s == 'E') || (*s == 'e')) {
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| 315 | int eexp = 0, sign = 0;
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| 316 | s++;
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| 317 | if (*s == '+')
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| 318 | s++;
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| 319 | else if (*s=='-')
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| 320 | sign = 1, s++;
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| 321 |
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| 322 | for (; *s >= '0' && *s <= '9'; s++)
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| 323 | ADDTO(eexp, *s);
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| 324 | if (sign)
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| 325 | eexp = -eexp;
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| 326 | exp = exp + eexp;
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| 327 | }
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| 328 |
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| 329 | negexp = 1;
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| 330 | if (exp<0) {
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| 331 | negexp = -1;
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| 332 | exp = -exp;
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| 333 | }
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| 334 |
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| 335 |
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| 336 | flexp = soft_cast(1, INT);
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| 337 | exp5 = soft_cast(5, INT);
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| 338 | bexp = exp;
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| 339 | fl = soft_cast(mant, INT);
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| 340 |
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| 341 | for (; exp; exp >>= 1) {
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| 342 | if (exp&01)
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| 343 | flexp = soft_mul(flexp, exp5);
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| 344 | exp5 = soft_mul(exp5, exp5);
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| 345 | }
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| 346 | if (negexp<0)
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| 347 | fl = soft_div(fl, flexp);
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| 348 | else
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| 349 | fl = soft_mul(fl, flexp);
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| 350 |
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| 351 | DEXPSET(fl, DEXP(fl) + negexp*bexp);
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| 352 | p = block(FCON, NIL, NIL, DOUBLE, 0, MKSUE(DOUBLE)); /* XXX type */
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| 353 | p->n_dcon = fl;
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| 354 | return p;
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| 355 | }
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| 356 | #else
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| 357 | #error missing softfloat definition
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| 358 | #endif
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| 359 | #endif
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