Markos Chandras | a79f5f9 | 2015-08-13 09:56:36 +0200 | [diff] [blame^] | 1 | /* |
| 2 | * IEEE754 floating point arithmetic |
| 3 | * double precision: MIN{,A}.f |
| 4 | * MIN : Scalar Floating-Point Minimum |
| 5 | * MINA: Scalar Floating-Point argument with Minimum Absolute Value |
| 6 | * |
| 7 | * MIN.D : FPR[fd] = minNum(FPR[fs],FPR[ft]) |
| 8 | * MINA.D: FPR[fd] = maxNumMag(FPR[fs],FPR[ft]) |
| 9 | * |
| 10 | * MIPS floating point support |
| 11 | * Copyright (C) 2015 Imagination Technologies, Ltd. |
| 12 | * Author: Markos Chandras <markos.chandras@imgtec.com> |
| 13 | * |
| 14 | * This program is free software; you can distribute it and/or modify it |
| 15 | * under the terms of the GNU General Public License as published by the |
| 16 | * Free Software Foundation; version 2 of the License. |
| 17 | */ |
| 18 | |
| 19 | #include "ieee754dp.h" |
| 20 | |
| 21 | union ieee754dp ieee754dp_fmax(union ieee754dp x, union ieee754dp y) |
| 22 | { |
| 23 | COMPXDP; |
| 24 | COMPYDP; |
| 25 | |
| 26 | EXPLODEXDP; |
| 27 | EXPLODEYDP; |
| 28 | |
| 29 | FLUSHXDP; |
| 30 | FLUSHYDP; |
| 31 | |
| 32 | ieee754_clearcx(); |
| 33 | |
| 34 | switch (CLPAIR(xc, yc)) { |
| 35 | case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_SNAN): |
| 36 | case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_SNAN): |
| 37 | case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_SNAN): |
| 38 | case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_SNAN): |
| 39 | case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_SNAN): |
| 40 | return ieee754dp_nanxcpt(y); |
| 41 | |
| 42 | case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_SNAN): |
| 43 | case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_QNAN): |
| 44 | case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_ZERO): |
| 45 | case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_NORM): |
| 46 | case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_DNORM): |
| 47 | case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_INF): |
| 48 | return ieee754dp_nanxcpt(x); |
| 49 | |
| 50 | /* numbers are preferred to NaNs */ |
| 51 | case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_QNAN): |
| 52 | case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_QNAN): |
| 53 | case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_QNAN): |
| 54 | case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_QNAN): |
| 55 | return x; |
| 56 | |
| 57 | case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_QNAN): |
| 58 | case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_ZERO): |
| 59 | case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_NORM): |
| 60 | case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_DNORM): |
| 61 | case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_INF): |
| 62 | return y; |
| 63 | |
| 64 | /* |
| 65 | * Infinity and zero handling |
| 66 | */ |
| 67 | case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_ZERO): |
| 68 | case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_NORM): |
| 69 | case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_DNORM): |
| 70 | case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO): |
| 71 | case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO): |
| 72 | return xs ? y : x; |
| 73 | |
| 74 | case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_INF): |
| 75 | case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_INF): |
| 76 | case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_INF): |
| 77 | case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF): |
| 78 | case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_NORM): |
| 79 | case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_DNORM): |
| 80 | return ys ? x : y; |
| 81 | |
| 82 | case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO): |
| 83 | if (xs == ys) |
| 84 | return x; |
| 85 | return ieee754dp_zero(1); |
| 86 | |
| 87 | case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM): |
| 88 | DPDNORMX; |
| 89 | |
| 90 | case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM): |
| 91 | DPDNORMY; |
| 92 | break; |
| 93 | |
| 94 | case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM): |
| 95 | DPDNORMX; |
| 96 | } |
| 97 | |
| 98 | /* Finally get to do some computation */ |
| 99 | |
| 100 | assert(xm & DP_HIDDEN_BIT); |
| 101 | assert(ym & DP_HIDDEN_BIT); |
| 102 | |
| 103 | /* Compare signs */ |
| 104 | if (xs > ys) |
| 105 | return y; |
| 106 | else if (xs < ys) |
| 107 | return x; |
| 108 | |
| 109 | /* Compare exponent */ |
| 110 | if (xe > ye) |
| 111 | return x; |
| 112 | else if (xe < ye) |
| 113 | return y; |
| 114 | |
| 115 | /* Compare mantissa */ |
| 116 | if (xm <= ym) |
| 117 | return y; |
| 118 | return x; |
| 119 | } |
| 120 | |
| 121 | union ieee754dp ieee754dp_fmaxa(union ieee754dp x, union ieee754dp y) |
| 122 | { |
| 123 | COMPXDP; |
| 124 | COMPYDP; |
| 125 | |
| 126 | EXPLODEXDP; |
| 127 | EXPLODEYDP; |
| 128 | |
| 129 | FLUSHXDP; |
| 130 | FLUSHYDP; |
| 131 | |
| 132 | ieee754_clearcx(); |
| 133 | |
| 134 | switch (CLPAIR(xc, yc)) { |
| 135 | case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_SNAN): |
| 136 | case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_SNAN): |
| 137 | case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_SNAN): |
| 138 | case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_SNAN): |
| 139 | case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_SNAN): |
| 140 | return ieee754dp_nanxcpt(y); |
| 141 | |
| 142 | case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_SNAN): |
| 143 | case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_QNAN): |
| 144 | case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_ZERO): |
| 145 | case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_NORM): |
| 146 | case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_DNORM): |
| 147 | case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_INF): |
| 148 | return ieee754dp_nanxcpt(x); |
| 149 | |
| 150 | /* numbers are preferred to NaNs */ |
| 151 | case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_QNAN): |
| 152 | case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_QNAN): |
| 153 | case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_QNAN): |
| 154 | case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_QNAN): |
| 155 | return x; |
| 156 | |
| 157 | case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_QNAN): |
| 158 | case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_ZERO): |
| 159 | case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_NORM): |
| 160 | case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_DNORM): |
| 161 | case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_INF): |
| 162 | return y; |
| 163 | |
| 164 | /* |
| 165 | * Infinity and zero handling |
| 166 | */ |
| 167 | case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_ZERO): |
| 168 | case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_NORM): |
| 169 | case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_DNORM): |
| 170 | case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO): |
| 171 | case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO): |
| 172 | return x; |
| 173 | |
| 174 | case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_INF): |
| 175 | case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_INF): |
| 176 | case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_INF): |
| 177 | case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF): |
| 178 | case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_NORM): |
| 179 | case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_DNORM): |
| 180 | return y; |
| 181 | |
| 182 | case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO): |
| 183 | if (xs == ys) |
| 184 | return x; |
| 185 | return ieee754dp_zero(1); |
| 186 | |
| 187 | case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM): |
| 188 | DPDNORMX; |
| 189 | |
| 190 | case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM): |
| 191 | DPDNORMY; |
| 192 | break; |
| 193 | |
| 194 | case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM): |
| 195 | DPDNORMX; |
| 196 | } |
| 197 | |
| 198 | /* Finally get to do some computation */ |
| 199 | |
| 200 | assert(xm & DP_HIDDEN_BIT); |
| 201 | assert(ym & DP_HIDDEN_BIT); |
| 202 | |
| 203 | /* Compare exponent */ |
| 204 | if (xe > ye) |
| 205 | return x; |
| 206 | else if (xe < ye) |
| 207 | return y; |
| 208 | |
| 209 | /* Compare mantissa */ |
| 210 | if (xm <= ym) |
| 211 | return y; |
| 212 | return x; |
| 213 | } |