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a50079b7ff
implement a deprecated FPU control interface in addition to the standard one. To make this clearer, further deprecate ieeefp.h by not declaring the function prototypes except on architectures that implement them already. Currently i386 and amd64 implement the ieeefp.h interface for compatibility, and for fp[gs]etprec(), which doesn't exist on most other hardware. Powerpc, sparc64, and ia64 partially implement it and probably shouldn't, and other architectures don't implement it at all.
259 lines
6.6 KiB
C
259 lines
6.6 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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* Deprecated historical FPU control interface
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*
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* IEEE floating point type, constant and function definitions.
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* XXX: FP*FLD and FP*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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* 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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#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 __fnclex() __asm __volatile("fnclex")
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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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/*
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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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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 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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return (_p);
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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 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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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;
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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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return ((fp_except_t)_ex);
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}
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static __inline fp_except_t
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fpresetsticky(fp_except_t _m)
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{
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struct {
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unsigned _cw;
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unsigned _sw;
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unsigned _other[5];
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} _env;
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fp_except_t _p;
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_m &= FP_STKY_FLD >> FP_STKY_OFF;
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_p = fpgetsticky();
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if ((_p & ~_m) == _p)
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return (_p);
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if ((_p & ~_m) == 0) {
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__fnclex();
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return (_p);
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}
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__fnstenv(&_env);
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_env._sw &= ~_m;
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__fldenv(&_env);
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return (_p);
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}
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#endif /* __GNUCLIKE_ASM */
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#endif /* !_MACHINE_IEEEFP_H_ */
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