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
185 lines
5.5 KiB
C
185 lines
5.5 KiB
C
/*-
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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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* 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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#ifdef __GNUCLIKE_ASM
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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 __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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/*
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* return the contents of a FP register
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*/
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static __inline__ int
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__fpgetreg(int _reg)
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{
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unsigned short _mem;
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/*-
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* This is more efficient than it looks. The switch gets optimized
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* away if _reg is constant.
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*
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* The default case only supports _reg == 0. We could handle more
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* registers (e.g., tags) using fnstenv, but the interface doesn't
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* support more.
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*/
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switch(_reg) {
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default:
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__fnstcw(&_mem);
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break;
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case FP_STKY_REG:
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__fnstsw(&_mem);
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break;
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}
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return _mem;
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}
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/*
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* set a FP mode; return previous mode
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*/
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static __inline__ int
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__fpsetreg(int _m, int _reg, int _fld, int _off)
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{
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unsigned _env[7];
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unsigned _p;
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/*
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* _reg == 0 could be handled better using fnstcw/fldcw.
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*/
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__fnstenv(_env);
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_p = (_env[_reg] & _fld) >> _off;
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_env[_reg] = (_env[_reg] & ~_fld) | (_m << _off & _fld);
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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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/*
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* SysV/386 FP control interface
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*/
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#define fpgetround() ((fp_rnd_t) \
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((__fpgetreg(FP_RND_REG) & FP_RND_FLD) >> FP_RND_OFF))
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#define fpsetround(m) ((fp_rnd_t) \
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__fpsetreg((m), FP_RND_REG, FP_RND_FLD, FP_RND_OFF))
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#define fpgetprec() ((fp_prec_t) \
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((__fpgetreg(FP_PRC_REG) & FP_PRC_FLD) >> FP_PRC_OFF))
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#define fpsetprec(m) ((fp_prec_t) \
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__fpsetreg((m), FP_PRC_REG, FP_PRC_FLD, FP_PRC_OFF))
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#define fpgetmask() ((fp_except_t) \
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((~__fpgetreg(FP_MSKS_REG) & FP_MSKS_FLD) >> FP_MSKS_OFF))
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#define fpsetmask(m) ((fp_except_t) \
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(~__fpsetreg(~(m), FP_MSKS_REG, FP_MSKS_FLD, FP_MSKS_OFF)) & \
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(FP_MSKS_FLD >> FP_MSKS_OFF))
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#define fpgetsticky() ((fp_except_t) \
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((__fpgetreg(FP_STKY_REG) & FP_STKY_FLD) >> FP_STKY_OFF))
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#define fpresetsticky(m) ((fp_except_t) \
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__fpsetreg(0, FP_STKY_REG, (m), FP_STKY_OFF))
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/* Suppress prototypes in the MI header. */
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#define _IEEEFP_INLINED_ 1
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#endif /* !_MACHINE_IEEEFP_H_ */
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