^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1) // SPDX-License-Identifier: GPL-2.0-only
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2) /* IEEE754 floating point arithmetic
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3) * single precision
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6) * MIPS floating point support
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7) * Copyright (C) 1994-2000 Algorithmics Ltd.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 8) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 9)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) #include "ieee754sp.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) union ieee754sp ieee754sp_mul(union ieee754sp x, union ieee754sp y)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) int re;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) int rs;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) unsigned int rm;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) unsigned short lxm;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) unsigned short hxm;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) unsigned short lym;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) unsigned short hym;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) unsigned int lrm;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) unsigned int hrm;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) unsigned int t;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) unsigned int at;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) COMPXSP;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) COMPYSP;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) EXPLODEXSP;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) EXPLODEYSP;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) ieee754_clearcx();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) FLUSHXSP;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) FLUSHYSP;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) switch (CLPAIR(xc, yc)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_SNAN):
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_SNAN):
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_SNAN):
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_SNAN):
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_SNAN):
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) return ieee754sp_nanxcpt(y);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_SNAN):
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_QNAN):
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_ZERO):
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_NORM):
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_DNORM):
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_INF):
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) return ieee754sp_nanxcpt(x);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_QNAN):
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_QNAN):
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_QNAN):
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_QNAN):
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) return y;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_QNAN):
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_ZERO):
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_NORM):
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_DNORM):
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_INF):
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64) return x;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68) * Infinity handling
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_ZERO):
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71) case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF):
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) ieee754_setcx(IEEE754_INVALID_OPERATION);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73) return ieee754sp_indef();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75) case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_INF):
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76) case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_INF):
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77) case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_NORM):
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78) case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_DNORM):
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79) case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_INF):
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80) return ieee754sp_inf(xs ^ ys);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82) case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO):
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83) case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_NORM):
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84) case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_DNORM):
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85) case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO):
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86) case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO):
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 87) return ieee754sp_zero(xs ^ ys);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 88)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 89)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 90) case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM):
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 91) SPDNORMX;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 92) fallthrough;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 93) case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM):
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 94) SPDNORMY;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 95) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 96)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 97) case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM):
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 98) SPDNORMX;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 99) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_NORM):
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) /* rm = xm * ym, re = xe+ye basically */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) assert(xm & SP_HIDDEN_BIT);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) assert(ym & SP_HIDDEN_BIT);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) re = xe + ye;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) rs = xs ^ ys;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) /* shunt to top of word */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) xm <<= 32 - (SP_FBITS + 1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) ym <<= 32 - (SP_FBITS + 1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) * Multiply 32 bits xm, ym to give high 32 bits rm with stickness.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) lxm = xm & 0xffff;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) hxm = xm >> 16;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) lym = ym & 0xffff;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) hym = ym >> 16;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) lrm = lxm * lym; /* 16 * 16 => 32 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) hrm = hxm * hym; /* 16 * 16 => 32 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) t = lxm * hym; /* 16 * 16 => 32 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) at = lrm + (t << 16);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) hrm += at < lrm;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) lrm = at;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) hrm = hrm + (t >> 16);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) t = hxm * lym; /* 16 * 16 => 32 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) at = lrm + (t << 16);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) hrm += at < lrm;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) lrm = at;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) hrm = hrm + (t >> 16);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) rm = hrm | (lrm != 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) * Sticky shift down to normal rounding precision.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) if ((int) rm < 0) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) rm = (rm >> (32 - (SP_FBITS + 1 + 3))) |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) ((rm << (SP_FBITS + 1 + 3)) != 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) re++;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) } else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) rm = (rm >> (32 - (SP_FBITS + 1 + 3 + 1))) |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) ((rm << (SP_FBITS + 1 + 3 + 1)) != 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) assert(rm & (SP_HIDDEN_BIT << 3));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) return ieee754sp_format(rs, re, rm);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) }