/* FPU control word bits. x86 version.
Copyright (C) 1993-2021 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Olaf Flebbe.
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
<https://www.gnu.org/licenses/>. */
#ifndef _FPU_CONTROL_H
#define _FPU_CONTROL_H 1
/* Note that this file sets on x86-64 only the x87 FPU, it does not
touch the SSE unit. */
/* Here is the dirty part. Set up your 387 through the control word
* (cw) register.
*
* 15-13 12 11-10 9-8 7-6 5 4 3 2 1 0
* | reserved | IC | RC | PC | reserved | PM | UM | OM | ZM | DM | IM
*
* IM: Invalid operation mask
* DM: Denormalized operand mask
* ZM: Zero-divide mask
* OM: Overflow mask
* UM: Underflow mask
* PM: Precision (inexact result) mask
*
* Mask bit is 1 means no interrupt.
*
* PC: Precision control
* 11 - round to extended precision
* 10 - round to double precision
* 00 - round to single precision
*
* RC: Rounding control
* 00 - rounding to nearest
* 01 - rounding down (toward - infinity)
* 10 - rounding up (toward + infinity)
* 11 - rounding toward zero
*
* IC: Infinity control
* That is for 8087 and 80287 only.
*
* The hardware default is 0x037f which we use.
*/
#include <features.h>
/* masking of interrupts */
#define _FPU_MASK_IM 0x01
#define _FPU_MASK_DM 0x02
#define _FPU_MASK_ZM 0x04
#define _FPU_MASK_OM 0x08
#define _FPU_MASK_UM 0x10
#define _FPU_MASK_PM 0x20
/* precision control */
#define _FPU_EXTENDED 0x300 /* libm requires double extended precision. */
#define _FPU_DOUBLE 0x200
#define _FPU_SINGLE 0x0
/* rounding control */
#define _FPU_RC_NEAREST 0x0 /* RECOMMENDED */
#define _FPU_RC_DOWN 0x400
#define _FPU_RC_UP 0x800
#define _FPU_RC_ZERO 0xC00
#define _FPU_RESERVED 0xF0C0 /* Reserved bits in cw */
/* The fdlibm code requires strict IEEE double precision arithmetic,
and no interrupts for exceptions, rounding to nearest. */
#define _FPU_DEFAULT 0x037f
/* IEEE: same as above. */
#define _FPU_IEEE 0x037f
/* Type of the control word. */
typedef unsigned int fpu_control_t __attribute__ ((__mode__ (__HI__)));
/* Macros for accessing the hardware control word. "*&" is used to
work around a bug in older versions of GCC. __volatile__ is used
to support combination of writing the control register and reading
it back. Without __volatile__, the old value may be used for reading
back under compiler optimization.
Note that the use of these macros is not sufficient anymore with
recent hardware nor on x86-64. Some floating point operations are
executed in the SSE/SSE2 engines which have their own control and
status register. */
#define _FPU_GETCW(cw) __asm__ __volatile__ ("fnstcw %0" : "=m" (*&cw))
#define _FPU_SETCW(cw) __asm__ __volatile__ ("fldcw %0" : : "m" (*&cw))
/* Default control word set at startup. */
extern fpu_control_t __fpu_control;
#endif /* fpu_control.h */
Directory Contents
Dirs: 54 × Files: 161
!"#$%&'(()*+,-./00123456789 t\
wIDATx ]ys 47Y ƒ - " Rv < f{Ɛ $k l L > L ~h^ 1 [ r G t& h
l F z3O Y ! p A(_g̷ E8 )S 8 c Kb"z ~ 5 J xAL WU < *
5 m;W a pB h ~P J
2 3 6 ҙ .Ƹ P i 4g
F R L P ΪK/D M v (a3
k J
Œ4N5* SH ` SdJ z O J Xՠ V> u ߱ BE&L b2 ?2` tX+ c CB A$ i b C ĀMB E : / # Dx &l =q Ty 0 \p I ( L Ǎ { e
4k ;`u^ｦ eP!( d { )T A 8 O;Ě n >;s6 ! :Nx `[S D HU ~ qJ F}
a g*D 49 / pn k h (t 8NxƐF _!r չ7
ZR R q/5") Ӎ NY 0 x sZ! o
fu , K"$ ? pg 㕣= 1» {h " fh7
y } +7 $ y
" X ą - G P u 4 m >J 5 L =V ' ^@I p ?MS xЌ XV P ! h "C NS9B8̢ ]!K e zA , ӏkbY !< XQ ٿyS| *" f { w 4@[S <
# 0 ! js [m =,~ o
"ݎ DHf Wo $ g ! Vԅ t mB /y Wf V4 c+@x? B ~u " xUN e 0 BĂ)
~J pz!
7 y6]l Ԥ@ P a< O /DHC `≻ N m"$ 0ObB }{ x AO FCG D R ^ "B { WDH UR l@ T
# +"d T ; 0 i D}. 7 ` ' ] w rE &S i ƕiTD EL P _ u h $ Ա FG wVD G L R Zf ' .!] J /ZR oGЍ s Mr Ĥ ʬ 3 Q [3 cL ` ^ p +
( F;# B 5 ' 2Y f [ ϶R0e } E 7
6M aۮ H <& n % L] E}Up x紉, Uw' Q Ǯշo k ވۙ 0N94 VX5 xEDE l D #֤ } C o )W : ^ s 9 bRf iX5u ཱི 4 :[ T 1. | [E 2ؽ Iy\ : o x K G 5
ylP ' uK E
ftb/i[3 .g _ [3M n
G, #NwQ5~
ؚ) | n =Ц"x qg gB ` 듘 ~ x w ?
?
R~ _ u. &V Q K˻ H C ( TN˄+ `C dA n B D 3"Z G ê ^k H_ /- ~ " R_ .8 Z_ 6@ o xg uP ? 3լ @7AM! E7^
- =V L x g-D0 CtmW 7 O G _ WD0 g C w1 r
d w : a | \ *" f nֳ ^ H# f L ` Z ۽hV }S F r0Ù Bć5r] @! NL iQ]{s^=4 d WD " " M;
t" 8 5 e dL| "-*st" ) SWD ?R[S e ooF 20.D ? bo =) A i o d ģ ZҰaO
@E =) i D a &ܟa CϞ y6 ,<%{^x%{f8? `iw^ ?/
M
* IEND B`