diff options
author | Yunhong Jiang <yunhong.jiang@intel.com> | 2015-08-04 12:17:53 -0700 |
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committer | Yunhong Jiang <yunhong.jiang@intel.com> | 2015-08-04 15:44:42 -0700 |
commit | 9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (patch) | |
tree | 1c9cafbcd35f783a87880a10f85d1a060db1a563 /kernel/arch/mips/math-emu/sp_sqrt.c | |
parent | 98260f3884f4a202f9ca5eabed40b1354c489b29 (diff) |
Add the rt linux 4.1.3-rt3 as base
Import the rt linux 4.1.3-rt3 as OPNFV kvm base.
It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and
the base is:
commit 0917f823c59692d751951bf5ea699a2d1e2f26a2
Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Sat Jul 25 12:13:34 2015 +0200
Prepare v4.1.3-rt3
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
We lose all the git history this way and it's not good. We
should apply another opnfv project repo in future.
Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423
Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
Diffstat (limited to 'kernel/arch/mips/math-emu/sp_sqrt.c')
-rw-r--r-- | kernel/arch/mips/math-emu/sp_sqrt.c | 114 |
1 files changed, 114 insertions, 0 deletions
diff --git a/kernel/arch/mips/math-emu/sp_sqrt.c b/kernel/arch/mips/math-emu/sp_sqrt.c new file mode 100644 index 000000000..67059c33a --- /dev/null +++ b/kernel/arch/mips/math-emu/sp_sqrt.c @@ -0,0 +1,114 @@ +/* IEEE754 floating point arithmetic + * single precision square root + */ +/* + * MIPS floating point support + * Copyright (C) 1994-2000 Algorithmics Ltd. + * + * This program is free software; you can distribute it and/or modify it + * under the terms of the GNU General Public License (Version 2) as + * published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License + * for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +#include "ieee754sp.h" + +union ieee754sp ieee754sp_sqrt(union ieee754sp x) +{ + int ix, s, q, m, t, i; + unsigned int r; + COMPXSP; + + /* take care of Inf and NaN */ + + EXPLODEXSP; + ieee754_clearcx(); + FLUSHXSP; + + /* x == INF or NAN? */ + switch (xc) { + case IEEE754_CLASS_SNAN: + return ieee754sp_nanxcpt(x); + + case IEEE754_CLASS_QNAN: + /* sqrt(Nan) = Nan */ + return x; + + case IEEE754_CLASS_ZERO: + /* sqrt(0) = 0 */ + return x; + + case IEEE754_CLASS_INF: + if (xs) { + /* sqrt(-Inf) = Nan */ + ieee754_setcx(IEEE754_INVALID_OPERATION); + return ieee754sp_indef(); + } + /* sqrt(+Inf) = Inf */ + return x; + + case IEEE754_CLASS_DNORM: + case IEEE754_CLASS_NORM: + if (xs) { + /* sqrt(-x) = Nan */ + ieee754_setcx(IEEE754_INVALID_OPERATION); + return ieee754sp_indef(); + } + break; + } + + ix = x.bits; + + /* normalize x */ + m = (ix >> 23); + if (m == 0) { /* subnormal x */ + for (i = 0; (ix & 0x00800000) == 0; i++) + ix <<= 1; + m -= i - 1; + } + m -= 127; /* unbias exponent */ + ix = (ix & 0x007fffff) | 0x00800000; + if (m & 1) /* odd m, double x to make it even */ + ix += ix; + m >>= 1; /* m = [m/2] */ + + /* generate sqrt(x) bit by bit */ + ix += ix; + q = s = 0; /* q = sqrt(x) */ + r = 0x01000000; /* r = moving bit from right to left */ + + while (r != 0) { + t = s + r; + if (t <= ix) { + s = t + r; + ix -= t; + q += r; + } + ix += ix; + r >>= 1; + } + + if (ix != 0) { + ieee754_setcx(IEEE754_INEXACT); + switch (ieee754_csr.rm) { + case FPU_CSR_RU: + q += 2; + break; + case FPU_CSR_RN: + q += (q & 1); + break; + } + } + ix = (q >> 1) + 0x3f000000; + ix += (m << 23); + x.bits = ix; + return x; +} |