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Diffstat (limited to '')
| -rw-r--r-- | arch/mips/math-emu/sp_fmax.c | 252 |
1 files changed, 252 insertions, 0 deletions
diff --git a/arch/mips/math-emu/sp_fmax.c b/arch/mips/math-emu/sp_fmax.c new file mode 100644 index 000000000..3fb16a1df --- /dev/null +++ b/arch/mips/math-emu/sp_fmax.c @@ -0,0 +1,252 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * IEEE754 floating point arithmetic + * single precision: MAX{,A}.f + * MAX : Scalar Floating-Point Maximum + * MAXA: Scalar Floating-Point argument with Maximum Absolute Value + * + * MAX.S : FPR[fd] = maxNum(FPR[fs],FPR[ft]) + * MAXA.S: FPR[fd] = maxNumMag(FPR[fs],FPR[ft]) + * + * MIPS floating point support + * Copyright (C) 2015 Imagination Technologies, Ltd. + * Author: Markos Chandras <markos.chandras@imgtec.com> + */ + +#include "ieee754sp.h" + +union ieee754sp ieee754sp_fmax(union ieee754sp x, union ieee754sp y) +{ + COMPXSP; + COMPYSP; + + EXPLODEXSP; + EXPLODEYSP; + + FLUSHXSP; + FLUSHYSP; + + ieee754_clearcx(); + + 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 ieee754sp_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 ieee754sp_nanxcpt(x); + + /* + * Quiet NaN handling + */ + + /* + * The case of both inputs quiet NaNs + */ + case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_QNAN): + return x; + + /* + * The cases of exactly one input quiet NaN (numbers + * are here preferred as returned values to NaNs) + */ + 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 x; + + 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 y; + + /* + * Infinity and zero handling + */ + case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_ZERO): + case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_NORM): + case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_DNORM): + case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO): + case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO): + return xs ? y : x; + + case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_INF): + case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_INF): + case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_INF): + case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF): + case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_NORM): + case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_DNORM): + return ys ? x : y; + + case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO): + return ieee754sp_zero(xs & ys); + + case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM): + SPDNORMX; + fallthrough; + case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM): + SPDNORMY; + break; + + case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM): + SPDNORMX; + } + + /* Finally get to do some computation */ + + assert(xm & SP_HIDDEN_BIT); + assert(ym & SP_HIDDEN_BIT); + + /* Compare signs */ + if (xs > ys) + return y; + else if (xs < ys) + return x; + + /* Signs of inputs are equal, let's compare exponents */ + if (xs == 0) { + /* Inputs are both positive */ + if (xe > ye) + return x; + else if (xe < ye) + return y; + } else { + /* Inputs are both negative */ + if (xe > ye) + return y; + else if (xe < ye) + return x; + } + + /* Signs and exponents of inputs are equal, let's compare mantissas */ + if (xs == 0) { + /* Inputs are both positive, with equal signs and exponents */ + if (xm <= ym) + return y; + return x; + } + /* Inputs are both negative, with equal signs and exponents */ + if (xm <= ym) + return x; + return y; +} + +union ieee754sp ieee754sp_fmaxa(union ieee754sp x, union ieee754sp y) +{ + COMPXSP; + COMPYSP; + + EXPLODEXSP; + EXPLODEYSP; + + FLUSHXSP; + FLUSHYSP; + + ieee754_clearcx(); + + 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 ieee754sp_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 ieee754sp_nanxcpt(x); + + /* + * Quiet NaN handling + */ + + /* + * The case of both inputs quiet NaNs + */ + case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_QNAN): + return x; + + /* + * The cases of exactly one input quiet NaN (numbers + * are here preferred as returned values to NaNs) + */ + 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 x; + + 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 y; + + /* + * Infinity and zero handling + */ + case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_INF): + return ieee754sp_inf(xs & ys); + + case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_ZERO): + case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_NORM): + case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_DNORM): + case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO): + case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO): + return x; + + case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_INF): + case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_INF): + case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF): + case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_NORM): + case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_DNORM): + return y; + + case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO): + return ieee754sp_zero(xs & ys); + + case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM): + SPDNORMX; + fallthrough; + case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM): + SPDNORMY; + break; + + case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM): + SPDNORMX; + } + + /* Finally get to do some computation */ + + assert(xm & SP_HIDDEN_BIT); + assert(ym & SP_HIDDEN_BIT); + + /* Compare exponent */ + if (xe > ye) + return x; + else if (xe < ye) + return y; + + /* Compare mantissa */ + if (xm < ym) + return y; + else if (xm > ym) + return x; + else if (xs == 0) + return x; + return y; +} |