diff options
Diffstat (limited to 'arch/mips/math-emu/dp_mul.c')
| -rw-r--r-- | arch/mips/math-emu/dp_mul.c | 159 |
1 files changed, 159 insertions, 0 deletions
diff --git a/arch/mips/math-emu/dp_mul.c b/arch/mips/math-emu/dp_mul.c new file mode 100644 index 0000000000..8a671bb7af --- /dev/null +++ b/arch/mips/math-emu/dp_mul.c @@ -0,0 +1,159 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* IEEE754 floating point arithmetic + * double precision: common utilities + */ +/* + * MIPS floating point support + * Copyright (C) 1994-2000 Algorithmics Ltd. + */ + +#include "ieee754dp.h" + +union ieee754dp ieee754dp_mul(union ieee754dp x, union ieee754dp y) +{ + int re; + int rs; + u64 rm; + unsigned int lxm; + unsigned int hxm; + unsigned int lym; + unsigned int hym; + u64 lrm; + u64 hrm; + u64 t; + u64 at; + + COMPXDP; + COMPYDP; + + EXPLODEXDP; + EXPLODEYDP; + + ieee754_clearcx(); + + FLUSHXDP; + FLUSHYDP; + + switch (CLPAIR(xc, yc)) { + case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_SNAN): + case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_SNAN): + case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_SNAN): + case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_SNAN): + case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_SNAN): + return ieee754dp_nanxcpt(y); + + case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_SNAN): + case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_QNAN): + case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_ZERO): + case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_NORM): + case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_DNORM): + case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_INF): + return ieee754dp_nanxcpt(x); + + case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_QNAN): + case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_QNAN): + case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_QNAN): + case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_QNAN): + return y; + + case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_QNAN): + case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_ZERO): + case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_NORM): + case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_DNORM): + case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_INF): + return x; + + + /* + * Infinity handling + */ + case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_ZERO): + case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF): + ieee754_setcx(IEEE754_INVALID_OPERATION); + return ieee754dp_indef(); + + case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_INF): + case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_INF): + case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_NORM): + case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_DNORM): + case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_INF): + return ieee754dp_inf(xs ^ ys); + + case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO): + case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_NORM): + case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_DNORM): + case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO): + case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO): + return ieee754dp_zero(xs ^ ys); + + + case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM): + DPDNORMX; + fallthrough; + case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM): + DPDNORMY; + break; + + case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM): + DPDNORMX; + break; + + case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_NORM): + break; + } + /* rm = xm * ym, re = xe+ye basically */ + assert(xm & DP_HIDDEN_BIT); + assert(ym & DP_HIDDEN_BIT); + + re = xe + ye; + rs = xs ^ ys; + + /* shunt to top of word */ + xm <<= 64 - (DP_FBITS + 1); + ym <<= 64 - (DP_FBITS + 1); + + /* + * Multiply 64 bits xm, ym to give high 64 bits rm with stickness. + */ + + lxm = xm; + hxm = xm >> 32; + lym = ym; + hym = ym >> 32; + + lrm = DPXMULT(lxm, lym); + hrm = DPXMULT(hxm, hym); + + t = DPXMULT(lxm, hym); + + at = lrm + (t << 32); + hrm += at < lrm; + lrm = at; + + hrm = hrm + (t >> 32); + + t = DPXMULT(hxm, lym); + + at = lrm + (t << 32); + hrm += at < lrm; + lrm = at; + + hrm = hrm + (t >> 32); + + rm = hrm | (lrm != 0); + + /* + * Sticky shift down to normal rounding precision. + */ + if ((s64) rm < 0) { + rm = (rm >> (64 - (DP_FBITS + 1 + 3))) | + ((rm << (DP_FBITS + 1 + 3)) != 0); + re++; + } else { + rm = (rm >> (64 - (DP_FBITS + 1 + 3 + 1))) | + ((rm << (DP_FBITS + 1 + 3 + 1)) != 0); + } + assert(rm & (DP_HIDDEN_BIT << 3)); + + return ieee754dp_format(rs, re, rm); +} |