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/* floor function, sparc64 version.
Copyright (C) 2012 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by David S. Miller <davem@davemloft.net>, 2012.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <sysdep.h>
/* Since changing the rounding mode is extremely expensive, we
try to round up using a method that is rounding mode
agnostic.
We add then subtract (or subtract than add if the initial
value was negative) 2**23 to the value, then subtract it
back out.
This will clear out the fractional portion of the value.
One of two things will happen for non-whole initial values.
Either the rounding mode will round it up, or it will be
rounded down. If the value started out whole, it will be
equal after the addition and subtraction. This means we
can accurately detect with one test whether we need to add
another 1.0 to round it up properly.
We pop constants into the FPU registers using the incoming
argument stack slots, since this avoid having to use any
PIC references. We also thus avoid having to allocate a
register window.
VIS instructions are used to facilitate the formation of
easier constants, and the propagation of the sign bit. */
#define TWO_FIFTYTWO 0x43300000 /* 2**52 */
#define ONE_DOT_ZERO 0x3ff00000 /* 1.0 */
#define ZERO %f10 /* 0.0 */
#define SIGN_BIT %f12 /* -0.0 */
ENTRY (__floor)
sethi %hi(TWO_FIFTYTWO), %o2
sethi %hi(ONE_DOT_ZERO), %o3
fzero ZERO
sllx %o2, 32, %o2
fnegd ZERO, SIGN_BIT
sllx %o3, 32, %o3
stx %o2, [%sp + STACK_BIAS + 128]
fabsd %f0, %f14
ldd [%sp + STACK_BIAS + 128], %f16
fcmpd %fcc3, %f14, %f16
fmovduge %fcc3, ZERO, %f16
fand %f0, SIGN_BIT, SIGN_BIT
for %f16, SIGN_BIT, %f16
faddd %f0, %f16, %f18
fsubd %f18, %f16, %f18
fcmpd %fcc2, %f18, %f0
stx %o3, [%sp + STACK_BIAS + 128]
ldd [%sp + STACK_BIAS + 128], %f20
fmovdule %fcc2, ZERO, %f20
fsubd %f18, %f20, %f0
fabsd %f0, %f0
retl
for %f0, SIGN_BIT, %f0
END (__floor)
weak_alias (__floor, floor)
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