19b6af98ec
performance in Xen's HVM mode.
304 lines
8.6 KiB
C
304 lines
8.6 KiB
C
/*-
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* Copyright (c) 2003 Peter Wemm.
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* Copyright (c) 1990 Andrew Moore, Talke Studio
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* from: @(#) ieeefp.h 1.0 (Berkeley) 9/23/93
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* $FreeBSD$
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*/
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#ifndef _MACHINE_IEEEFP_H_
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#define _MACHINE_IEEEFP_H_
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/*
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* IEEE floating point type, constant and function definitions.
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* XXX: {FP,SSE}*FLD and {FP,SSE}*OFF are undocumented pollution.
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*/
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#ifndef _SYS_CDEFS_H_
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#error this file needs sys/cdefs.h as a prerequisite
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#endif
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/*
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* Rounding modes.
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*/
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typedef enum {
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FP_RN=0, /* round to nearest */
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FP_RM, /* round down towards minus infinity */
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FP_RP, /* round up towards plus infinity */
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FP_RZ /* truncate */
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} fp_rnd_t;
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/*
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* Precision (i.e., rounding precision) modes.
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*/
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typedef enum {
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FP_PS=0, /* 24 bit (single-precision) */
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FP_PRS, /* reserved */
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FP_PD, /* 53 bit (double-precision) */
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FP_PE /* 64 bit (extended-precision) */
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} fp_prec_t;
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#define fp_except_t int
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/*
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* Exception bit masks.
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*/
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#define FP_X_INV 0x01 /* invalid operation */
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#define FP_X_DNML 0x02 /* denormal */
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#define FP_X_DZ 0x04 /* zero divide */
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#define FP_X_OFL 0x08 /* overflow */
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#define FP_X_UFL 0x10 /* underflow */
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#define FP_X_IMP 0x20 /* (im)precision */
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#define FP_X_STK 0x40 /* stack fault */
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/*
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* FPU control word bit-field masks.
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*/
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#define FP_MSKS_FLD 0x3f /* exception masks field */
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#define FP_PRC_FLD 0x300 /* precision control field */
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#define FP_RND_FLD 0xc00 /* rounding control field */
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/*
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* FPU status word bit-field masks.
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*/
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#define FP_STKY_FLD 0x3f /* sticky flags field */
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/*
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* SSE mxcsr register bit-field masks.
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*/
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#define SSE_STKY_FLD 0x3f /* exception flags */
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#define SSE_DAZ_FLD 0x40 /* Denormals are zero */
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#define SSE_MSKS_FLD 0x1f80 /* exception masks field */
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#define SSE_RND_FLD 0x6000 /* rounding control */
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#define SSE_FZ_FLD 0x8000 /* flush to zero on underflow */
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/*
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* FPU control word bit-field offsets (shift counts).
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*/
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#define FP_MSKS_OFF 0 /* exception masks offset */
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#define FP_PRC_OFF 8 /* precision control offset */
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#define FP_RND_OFF 10 /* rounding control offset */
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/*
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* FPU status word bit-field offsets (shift counts).
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*/
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#define FP_STKY_OFF 0 /* sticky flags offset */
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/*
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* SSE mxcsr register bit-field offsets (shift counts).
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*/
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#define SSE_STKY_OFF 0 /* exception flags offset */
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#define SSE_DAZ_OFF 6 /* DAZ exception mask offset */
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#define SSE_MSKS_OFF 7 /* other exception masks offset */
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#define SSE_RND_OFF 13 /* rounding control offset */
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#define SSE_FZ_OFF 15 /* flush to zero offset */
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#ifdef __GNUCLIKE_ASM
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#define __fldcw(addr) __asm __volatile("fldcw %0" : : "m" (*(addr)))
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#define __fldenv(addr) __asm __volatile("fldenv %0" : : "m" (*(addr)))
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#define __fnstcw(addr) __asm __volatile("fnstcw %0" : "=m" (*(addr)))
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#define __fnstenv(addr) __asm __volatile("fnstenv %0" : "=m" (*(addr)))
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#define __fnstsw(addr) __asm __volatile("fnstsw %0" : "=m" (*(addr)))
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#define __ldmxcsr(addr) __asm __volatile("ldmxcsr %0" : : "m" (*(addr)))
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#define __stmxcsr(addr) __asm __volatile("stmxcsr %0" : "=m" (*(addr)))
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/*
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* Load the control word. Be careful not to trap if there is a currently
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* unmasked exception (ones that will become freshly unmasked are not a
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* problem). This case must be handled by a save/restore of the
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* environment or even of the full x87 state. Accessing the environment
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* is very inefficient, so only do it when necessary.
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*/
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static __inline void
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__fnldcw(unsigned short _cw, unsigned short _newcw)
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{
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struct {
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unsigned _cw;
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unsigned _other[6];
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} _env;
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unsigned short _sw;
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if ((_cw & FP_MSKS_FLD) != FP_MSKS_FLD) {
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__fnstsw(&_sw);
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if (((_sw & ~_cw) & FP_STKY_FLD) != 0) {
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__fnstenv(&_env);
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_env._cw = _newcw;
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__fldenv(&_env);
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return;
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}
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}
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__fldcw(&_newcw);
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}
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/*
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* General notes about conflicting SSE vs FP status bits.
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* This code assumes that software will not fiddle with the control
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* bits of the SSE and x87 in such a way to get them out of sync and
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* still expect this to work. Break this at your peril.
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* Because I based this on the i386 port, the x87 state is used for
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* the fpget*() functions, and is shadowed into the SSE state for
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* the fpset*() functions. For dual source fpget*() functions, I
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* merge the two together. I think.
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*/
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static __inline fp_rnd_t
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__fpgetround(void)
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{
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unsigned short _cw;
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__fnstcw(&_cw);
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return ((fp_rnd_t)((_cw & FP_RND_FLD) >> FP_RND_OFF));
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}
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static __inline fp_rnd_t
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__fpsetround(fp_rnd_t _m)
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{
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fp_rnd_t _p;
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unsigned _mxcsr;
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unsigned short _cw, _newcw;
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__fnstcw(&_cw);
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_p = (fp_rnd_t)((_cw & FP_RND_FLD) >> FP_RND_OFF);
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_newcw = _cw & ~FP_RND_FLD;
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_newcw |= (_m << FP_RND_OFF) & FP_RND_FLD;
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__fnldcw(_cw, _newcw);
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__stmxcsr(&_mxcsr);
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_mxcsr &= ~SSE_RND_FLD;
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_mxcsr |= (_m << SSE_RND_OFF) & SSE_RND_FLD;
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__ldmxcsr(&_mxcsr);
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return (_p);
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}
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/*
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* Get or set the rounding precision for x87 arithmetic operations.
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* There is no equivalent SSE mode or control.
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*/
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static __inline fp_prec_t
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__fpgetprec(void)
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{
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unsigned short _cw;
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__fnstcw(&_cw);
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return ((fp_prec_t)((_cw & FP_PRC_FLD) >> FP_PRC_OFF));
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}
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static __inline fp_prec_t
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__fpsetprec(fp_prec_t _m)
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{
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fp_prec_t _p;
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unsigned short _cw, _newcw;
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__fnstcw(&_cw);
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_p = (fp_prec_t)((_cw & FP_PRC_FLD) >> FP_PRC_OFF);
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_newcw = _cw & ~FP_PRC_FLD;
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_newcw |= (_m << FP_PRC_OFF) & FP_PRC_FLD;
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__fnldcw(_cw, _newcw);
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return (_p);
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}
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/*
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* Get or set the exception mask.
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* Note that the x87 mask bits are inverted by the API -- a mask bit of 1
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* means disable for x87 and SSE, but for fp*mask() it means enable.
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*/
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static __inline fp_except_t
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__fpgetmask(void)
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{
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unsigned short _cw;
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__fnstcw(&_cw);
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return ((~_cw & FP_MSKS_FLD) >> FP_MSKS_OFF);
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}
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static __inline fp_except_t
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__fpsetmask(fp_except_t _m)
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{
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fp_except_t _p;
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unsigned _mxcsr;
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unsigned short _cw, _newcw;
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__fnstcw(&_cw);
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_p = (~_cw & FP_MSKS_FLD) >> FP_MSKS_OFF;
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_newcw = _cw & ~FP_MSKS_FLD;
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_newcw |= (~_m << FP_MSKS_OFF) & FP_MSKS_FLD;
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__fnldcw(_cw, _newcw);
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__stmxcsr(&_mxcsr);
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/* XXX should we clear non-ieee SSE_DAZ_FLD and SSE_FZ_FLD ? */
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_mxcsr &= ~SSE_MSKS_FLD;
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_mxcsr |= (~_m << SSE_MSKS_OFF) & SSE_MSKS_FLD;
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__ldmxcsr(&_mxcsr);
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return (_p);
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}
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static __inline fp_except_t
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__fpgetsticky(void)
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{
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unsigned _ex, _mxcsr;
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unsigned short _sw;
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__fnstsw(&_sw);
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_ex = (_sw & FP_STKY_FLD) >> FP_STKY_OFF;
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__stmxcsr(&_mxcsr);
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_ex |= (_mxcsr & SSE_STKY_FLD) >> SSE_STKY_OFF;
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return ((fp_except_t)_ex);
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}
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#endif /* __GNUCLIKE_ASM */
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#if !defined(__IEEEFP_NOINLINES__) && defined(__GNUCLIKE_ASM)
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#define fpgetmask() __fpgetmask()
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#define fpgetprec() __fpgetprec()
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#define fpgetround() __fpgetround()
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#define fpgetsticky() __fpgetsticky()
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#define fpsetmask(m) __fpsetmask(m)
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#define fpsetprec(m) __fpsetprec(m)
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#define fpsetround(m) __fpsetround(m)
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/* Suppress prototypes in the MI header. */
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#define _IEEEFP_INLINED_ 1
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#else /* !(!__IEEEFP_NOINLINES__ && __GNUCLIKE_ASM) */
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/* Augment the userland declarations. */
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__BEGIN_DECLS
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fp_prec_t fpgetprec(void);
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fp_prec_t fpsetprec(fp_prec_t);
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__END_DECLS
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#endif /* !__IEEEFP_NOINLINES__ && __GNUCLIKE_ASM */
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#endif /* !_MACHINE_IEEEFP_H_ */
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