7b74e4a759
to mistakes from day 1, it has always had semantics inconsistent with
SVR4 and its successors. In particular, given argument M:
- On Solaris and FreeBSD/{alpha,sparc64}, it clobbers the old flags
and *sets* the new flag word to M. (NetBSD, too?)
- On FreeBSD/{amd64,i386}, it *clears* the flags that are specified in M
and leaves the remaining flags unchanged (modulo a small bug on amd64.)
- On FreeBSD/ia64, it is not implemented.
There is no way to fix fpsetsticky() to DTRT for both old FreeBSD apps
and apps ported from other operating systems, so the best approach
seems to be to kill the function and fix any apps that break. I
couldn't find any ports that use it, and any such ports would already
be broken on FreeBSD/ia64 and Linux anyway.
By the way, the routine has always been undocumented in FreeBSD,
except for an MLINK to a manpage that doesn't describe it. This
manpage has stated since 5.3-RELEASE that the functions it describes
are deprecated, so that must mean that functions that it is *supposed*
to describe but doesn't are even *more* deprecated. ;-)
Note that fpresetsticky() has been retained on FreeBSD/i386. As far
as I can tell, no other operating systems or ports of FreeBSD
implement it, so there's nothing for it to be inconsistent with.
PR: 75862
Suggested by: bde
281 lines
8.0 KiB
C
281 lines
8.0 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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/*
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* IEEE floating point type and constant definitions.
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*/
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#ifndef _MACHINE_IEEEFP_H_
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#define _MACHINE_IEEEFP_H_
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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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* FP 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 to minus infinity */
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FP_RP, /* round up to plus infinity */
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FP_RZ /* truncate */
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} fp_rnd_t;
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/*
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* FP 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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* FP exception 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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* FP registers
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*/
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#define FP_MSKS_REG 0 /* exception masks */
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#define FP_PRC_REG 0 /* precision */
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#define FP_RND_REG 0 /* direction */
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#define FP_STKY_REG 1 /* sticky flags */
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/*
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* FP register 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 /* round control field */
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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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* FP register bit field offsets
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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 /* round control offset */
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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
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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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#if defined(__GNUCLIKE_ASM) && defined(__CC_SUPPORTS___INLINE__) \
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&& !defined(__cplusplus)
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#define __fldenv(addr) __asm __volatile("fldenv %0" : : "m" (*(addr)))
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#define __fnstenv(addr) __asm __volatile("fnstenv %0" : "=m" (*(addr)))
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#define __fldcw(addr) __asm __volatile("fldcw %0" : "=m" (*(addr)))
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#define __fnstcw(addr) __asm __volatile("fnstcw %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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* 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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/* Set rounding control */
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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 ((_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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unsigned short _cw;
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unsigned int _mxcsr;
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fp_rnd_t _p;
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__fnstcw(&_cw);
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_p = (_cw & FP_RND_FLD) >> FP_RND_OFF;
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_cw &= ~FP_RND_FLD;
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_cw |= (_m << FP_RND_OFF) & FP_RND_FLD;
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__fldcw(&_cw);
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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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* Set precision for fadd/fsub/fsqrt etc x87 instructions
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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 ((_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_rnd_t _m)
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{
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unsigned short _cw;
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fp_prec_t _p;
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__fnstcw(&_cw);
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_p = (_cw & FP_PRC_FLD) >> FP_PRC_OFF;
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_cw &= ~FP_PRC_FLD;
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_cw |= (_m << FP_PRC_OFF) & FP_PRC_FLD;
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__fldcw(&_cw);
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return (_p);
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}
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/*
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* Look at the exception masks
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* Note that x87 masks are inverse of the fp*() functions
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* API. ie: mask = 1 means disable for x87 and SSE, but
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* for the fp*() api, mask = 1 means enabled.
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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);
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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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unsigned short _cw;
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unsigned int _mxcsr;
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fp_except_t _p;
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__fnstcw(&_cw);
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_p = (~_cw) & FP_MSKS_FLD;
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_cw &= ~FP_MSKS_FLD;
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_cw |= (~_m) & FP_MSKS_FLD;
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__fldcw(&_cw);
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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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/* See which sticky exceptions are pending, and reset them */
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static __inline__ fp_except_t
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__fpgetsticky(void)
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{
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unsigned short _sw;
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unsigned int _mxcsr;
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fp_except_t _ex;
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__fnstsw(&_sw);
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_ex = _sw & FP_STKY_FLD;
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__stmxcsr(&_mxcsr);
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_ex |= _mxcsr & SSE_STKY_FLD;
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return (_ex);
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}
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#endif /* __GNUCLIKE_ASM && __CC_SUPPORTS___INLINE__ && !__cplusplus */
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#if !defined(__IEEEFP_NOINLINES__) && !defined(__cplusplus) \
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&& defined(__GNUCLIKE_ASM) && defined(__CC_SUPPORTS___INLINE__)
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#define fpgetround() __fpgetround()
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#define fpsetround(_m) __fpsetround(_m)
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#define fpgetprec() __fpgetprec()
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#define fpsetprec(_m) __fpsetprec(_m)
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#define fpgetmask() __fpgetmask()
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#define fpsetmask(_m) __fpsetmask(_m)
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#define fpgetsticky() __fpgetsticky()
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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__ && !__cplusplus && __GNUCLIKE_ASM
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&& __CC_SUPPORTS___INLINE__ */
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/* Augment the userland declarations */
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__BEGIN_DECLS
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extern fp_prec_t fpgetprec(void);
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extern fp_prec_t fpsetprec(fp_prec_t);
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__END_DECLS
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#endif /* !__IEEEFP_NOINLINES__ && !__cplusplus && __GNUCLIKE_ASM
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&& __CC_SUPPORTS___INLINE__ */
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#endif /* !_MACHINE_IEEEFP_H_ */
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