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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
commit | 2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch) | |
tree | 848558de17fb3008cdf4d861b01ac7781903ce39 /arch/mips/math-emu/dp_maddf.c | |
parent | Initial commit. (diff) | |
download | linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip |
Adding upstream version 6.1.76.upstream/6.1.76upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | arch/mips/math-emu/dp_maddf.c | 358 |
1 files changed, 358 insertions, 0 deletions
diff --git a/arch/mips/math-emu/dp_maddf.c b/arch/mips/math-emu/dp_maddf.c new file mode 100644 index 000000000..931e66f68 --- /dev/null +++ b/arch/mips/math-emu/dp_maddf.c @@ -0,0 +1,358 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * IEEE754 floating point arithmetic + * double precision: MADDF.f (Fused Multiply Add) + * MADDF.fmt: FPR[fd] = FPR[fd] + (FPR[fs] x FPR[ft]) + * + * MIPS floating point support + * Copyright (C) 2015 Imagination Technologies, Ltd. + * Author: Markos Chandras <markos.chandras@imgtec.com> + */ + +#include "ieee754dp.h" + + +/* 128 bits shift right logical with rounding. */ +static void srl128(u64 *hptr, u64 *lptr, int count) +{ + u64 low; + + if (count >= 128) { + *lptr = *hptr != 0 || *lptr != 0; + *hptr = 0; + } else if (count >= 64) { + if (count == 64) { + *lptr = *hptr | (*lptr != 0); + } else { + low = *lptr; + *lptr = *hptr >> (count - 64); + *lptr |= (*hptr << (128 - count)) != 0 || low != 0; + } + *hptr = 0; + } else { + low = *lptr; + *lptr = low >> count | *hptr << (64 - count); + *lptr |= (low << (64 - count)) != 0; + *hptr = *hptr >> count; + } +} + +static union ieee754dp _dp_maddf(union ieee754dp z, union ieee754dp x, + union ieee754dp y, enum maddf_flags flags) +{ + int re; + int rs; + unsigned int lxm; + unsigned int hxm; + unsigned int lym; + unsigned int hym; + u64 lrm; + u64 hrm; + u64 lzm; + u64 hzm; + u64 t; + u64 at; + int s; + + COMPXDP; + COMPYDP; + COMPZDP; + + EXPLODEXDP; + EXPLODEYDP; + EXPLODEZDP; + + FLUSHXDP; + FLUSHYDP; + FLUSHZDP; + + ieee754_clearcx(); + + rs = xs ^ ys; + if (flags & MADDF_NEGATE_PRODUCT) + rs ^= 1; + if (flags & MADDF_NEGATE_ADDITION) + zs ^= 1; + + /* + * Handle the cases when at least one of x, y or z is a NaN. + * Order of precedence is sNaN, qNaN and z, x, y. + */ + if (zc == IEEE754_CLASS_SNAN) + return ieee754dp_nanxcpt(z); + if (xc == IEEE754_CLASS_SNAN) + return ieee754dp_nanxcpt(x); + if (yc == IEEE754_CLASS_SNAN) + return ieee754dp_nanxcpt(y); + if (zc == IEEE754_CLASS_QNAN) + return z; + if (xc == IEEE754_CLASS_QNAN) + return x; + if (yc == IEEE754_CLASS_QNAN) + return y; + + if (zc == IEEE754_CLASS_DNORM) + DPDNORMZ; + /* ZERO z cases are handled separately below */ + + switch (CLPAIR(xc, yc)) { + + /* + * 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): + if ((zc == IEEE754_CLASS_INF) && (zs != rs)) { + /* + * Cases of addition of infinities with opposite signs + * or subtraction of infinities with same signs. + */ + ieee754_setcx(IEEE754_INVALID_OPERATION); + return ieee754dp_indef(); + } + /* + * z is here either not an infinity, or an infinity having the + * same sign as product (x*y). The result must be an infinity, + * and its sign is determined only by the sign of product (x*y). + */ + return ieee754dp_inf(rs); + + 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): + if (zc == IEEE754_CLASS_INF) + return ieee754dp_inf(zs); + if (zc == IEEE754_CLASS_ZERO) { + /* Handle cases +0 + (-0) and similar ones. */ + if (zs == rs) + /* + * Cases of addition of zeros of equal signs + * or subtraction of zeroes of opposite signs. + * The sign of the resulting zero is in any + * such case determined only by the sign of z. + */ + return z; + + return ieee754dp_zero(ieee754_csr.rm == FPU_CSR_RD); + } + /* x*y is here 0, and z is not 0, so just return z */ + return z; + + case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM): + DPDNORMX; + fallthrough; + case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM): + if (zc == IEEE754_CLASS_INF) + return ieee754dp_inf(zs); + DPDNORMY; + break; + + case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM): + if (zc == IEEE754_CLASS_INF) + return ieee754dp_inf(zs); + DPDNORMX; + break; + + case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_NORM): + if (zc == IEEE754_CLASS_INF) + return ieee754dp_inf(zs); + /* continue to real computations */ + } + + /* Finally get to do some computation */ + + /* + * Do the multiplication bit first + * + * rm = xm * ym, re = xe + ye basically + * + * At this point xm and ym should have been normalized. + */ + assert(xm & DP_HIDDEN_BIT); + assert(ym & DP_HIDDEN_BIT); + + re = xe + ye; + + /* shunt to top of word */ + xm <<= 64 - (DP_FBITS + 1); + ym <<= 64 - (DP_FBITS + 1); + + /* + * Multiply 64 bits xm and ym to give 128 bits result in hrm:lrm. + */ + + 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); + + /* Put explicit bit at bit 126 if necessary */ + if ((int64_t)hrm < 0) { + lrm = (hrm << 63) | (lrm >> 1); + hrm = hrm >> 1; + re++; + } + + assert(hrm & (1 << 62)); + + if (zc == IEEE754_CLASS_ZERO) { + /* + * Move explicit bit from bit 126 to bit 55 since the + * ieee754dp_format code expects the mantissa to be + * 56 bits wide (53 + 3 rounding bits). + */ + srl128(&hrm, &lrm, (126 - 55)); + return ieee754dp_format(rs, re, lrm); + } + + /* Move explicit bit from bit 52 to bit 126 */ + lzm = 0; + hzm = zm << 10; + assert(hzm & (1 << 62)); + + /* Make the exponents the same */ + if (ze > re) { + /* + * Have to shift y fraction right to align. + */ + s = ze - re; + srl128(&hrm, &lrm, s); + re += s; + } else if (re > ze) { + /* + * Have to shift x fraction right to align. + */ + s = re - ze; + srl128(&hzm, &lzm, s); + ze += s; + } + assert(ze == re); + assert(ze <= DP_EMAX); + + /* Do the addition */ + if (zs == rs) { + /* + * Generate 128 bit result by adding two 127 bit numbers + * leaving result in hzm:lzm, zs and ze. + */ + hzm = hzm + hrm + (lzm > (lzm + lrm)); + lzm = lzm + lrm; + if ((int64_t)hzm < 0) { /* carry out */ + srl128(&hzm, &lzm, 1); + ze++; + } + } else { + if (hzm > hrm || (hzm == hrm && lzm >= lrm)) { + hzm = hzm - hrm - (lzm < lrm); + lzm = lzm - lrm; + } else { + hzm = hrm - hzm - (lrm < lzm); + lzm = lrm - lzm; + zs = rs; + } + if (lzm == 0 && hzm == 0) + return ieee754dp_zero(ieee754_csr.rm == FPU_CSR_RD); + + /* + * Put explicit bit at bit 126 if necessary. + */ + if (hzm == 0) { + /* left shift by 63 or 64 bits */ + if ((int64_t)lzm < 0) { + /* MSB of lzm is the explicit bit */ + hzm = lzm >> 1; + lzm = lzm << 63; + ze -= 63; + } else { + hzm = lzm; + lzm = 0; + ze -= 64; + } + } + + t = 0; + while ((hzm >> (62 - t)) == 0) + t++; + + assert(t <= 62); + if (t) { + hzm = hzm << t | lzm >> (64 - t); + lzm = lzm << t; + ze -= t; + } + } + + /* + * Move explicit bit from bit 126 to bit 55 since the + * ieee754dp_format code expects the mantissa to be + * 56 bits wide (53 + 3 rounding bits). + */ + srl128(&hzm, &lzm, (126 - 55)); + + return ieee754dp_format(zs, ze, lzm); +} + +union ieee754dp ieee754dp_maddf(union ieee754dp z, union ieee754dp x, + union ieee754dp y) +{ + return _dp_maddf(z, x, y, 0); +} + +union ieee754dp ieee754dp_msubf(union ieee754dp z, union ieee754dp x, + union ieee754dp y) +{ + return _dp_maddf(z, x, y, MADDF_NEGATE_PRODUCT); +} + +union ieee754dp ieee754dp_madd(union ieee754dp z, union ieee754dp x, + union ieee754dp y) +{ + return _dp_maddf(z, x, y, 0); +} + +union ieee754dp ieee754dp_msub(union ieee754dp z, union ieee754dp x, + union ieee754dp y) +{ + return _dp_maddf(z, x, y, MADDF_NEGATE_ADDITION); +} + +union ieee754dp ieee754dp_nmadd(union ieee754dp z, union ieee754dp x, + union ieee754dp y) +{ + return _dp_maddf(z, x, y, MADDF_NEGATE_PRODUCT|MADDF_NEGATE_ADDITION); +} + +union ieee754dp ieee754dp_nmsub(union ieee754dp z, union ieee754dp x, + union ieee754dp y) +{ + return _dp_maddf(z, x, y, MADDF_NEGATE_PRODUCT); +} |