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Remove sparc64 specific parts of libm and fix comments

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Once upon a time, sparc64 was the only ld128 architecture. However,
both aarch64 and riscv are now such architectures. Many of the
comments about how slow multiplication was on old sparc64 processors
are now no longer true. However, since no evaluation has been done for
aarch64 yet, it's unclear if they are still relevant or not. If not,
the code should be changed. If so, the comments should remove the
uncertainty.

Reviewed by: emaste@
Differential Revision: https://reviews.freebsd.org/D23658
This commit is contained in:
Warner Losh 2020-02-26 18:55:03 +00:00
parent 8e0ff10d4b
commit a8197ad3aa
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=358347
9 changed files with 17 additions and 413 deletions
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3
lib/msun/ld128/k_expl.h
View File

@ -265,7 +265,8 @@ __k_expl(long double x, long double *hip, long double *lop, int *kp)
/*
* XXX: the rest of the functions are identical for ld80 and ld128.
* However, we should use scalbnl() for ld128, since long double
* multiplication is very slow on the only supported ld128 arch (sparc64).
* multiplication was very slow on sparc64 and no new evaluation has
* been made for aarch64 and/or riscv.
*/
static inline void

5
lib/msun/ld128/s_expl.c
View File

@ -92,7 +92,10 @@ expl(long double x)
t = SUM2P(hi, lo);
/* Scale by 2**k. */
/* XXX sparc64 multiplication is so slow that scalbnl() is faster. */
/*
* XXX sparc64 multiplication was so slow that scalbnl() is faster,
* but performance on aarch64 and riscv hasn't yet been quantified.
*/
if (k >= LDBL_MIN_EXP) {
if (k == LDBL_MAX_EXP)
RETURNI(t * 2 * 0x1p16383L);

21
lib/msun/ld128/s_logl.c
View File

@ -535,16 +535,17 @@ logl(long double x)
* efficiency than is gained.
*/
/*
* Use double precision operations wherever possible, since long
* double operations are emulated and are very slow on the only
* known machines that support ld128 (sparc64). Also, don't try
* to improve parallelism by increasing the number of operations,
* since any parallelism on such machines is needed for the
* emulation. Horner's method is good for this, and is also good
* for accuracy. Horner's method doesn't handle the `lo' term
* well, either for efficiency or accuracy. However, for accuracy
* we evaluate d * d * P2 separately to take advantage of
* by P2 being exact, and this gives a good place to sum the 'lo'
* Use double precision operations wherever possible, since
* long double operations are emulated and were very slow on
* the old sparc64 and unknown on the newer aarch64 and riscv
* machines. Also, don't try to improve parallelism by
* increasing the number of operations, since any parallelism
* on such machines is needed for the emulation. Horner's
* method is good for this, and is also good for accuracy.
* Horner's method doesn't handle the `lo' term well, either
* for efficiency or accuracy. However, for accuracy we
* evaluate d * d * P2 separately to take advantage of by P2
* being exact, and this gives a good place to sum the 'lo'
* term too.
*/
dd = (double)d;

5
lib/msun/sparc64/Makefile.inc
View File

@ -1,5 +0,0 @@
# $FreeBSD$
ARCH_SRCS= e_sqrt.S e_sqrtf.S
LDBL_PREC= 113
SYM_MAPS+= ${.CURDIR}/sparc64/Symbol.map

13
lib/msun/sparc64/Symbol.map
View File

@ -1,13 +0,0 @@
/*
* $FreeBSD$
*/
FBSD_1.0 {
};
FBSD_1.3 {
fesetexceptflag;
feraiseexcept;
fegetenv;
feholdexcept;
feupdateenv;
};

33
lib/msun/sparc64/e_sqrt.S
View File

@ -1,33 +0,0 @@
/*-
* Copyright (c) 2005 David Schultz <das@FreeBSD.ORG>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <machine/asm.h>
__FBSDID("$FreeBSD$")
ENTRY(sqrt)
retl
fsqrtd %f0, %f0
END(sqrt)

33
lib/msun/sparc64/e_sqrtf.S
View File

@ -1,33 +0,0 @@
/*-
* Copyright (c) 2005 David Schultz <das@FreeBSD.ORG>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <machine/asm.h>
__FBSDID("$FreeBSD$")
ENTRY(sqrtf)
retl
fsqrts %f1, %f0
END(sqrtf)

55
lib/msun/sparc64/fenv.c
View File

@ -1,55 +0,0 @@
/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2004 David Schultz <das@FreeBSD.ORG>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#define __fenv_static
#include "fenv.h"
#ifdef __GNUC_GNU_INLINE__
#error "This file must be compiled with C99 'inline' semantics"
#endif
/*
* The FSR_version field may be different on different
* implementations, but it is immutable and opaque to the
* application. Thus, 0 is valid as the default environment.
*/
const fenv_t __fe_dfl_env = 0;
extern inline int feclearexcept(int __excepts);
extern inline int fegetexceptflag(fexcept_t *__flagp, int __excepts);
extern inline int fesetexceptflag(const fexcept_t *__flagp, int __excepts);
extern inline int feraiseexcept(int __excepts);
extern inline int fetestexcept(int __excepts);
extern inline int fegetround(void);
extern inline int fesetround(int __round);
extern inline int fegetenv(fenv_t *__envp);
extern inline int feholdexcept(fenv_t *__envp);
extern inline int fesetenv(const fenv_t *__envp);
extern inline int feupdateenv(const fenv_t *__envp);

262
lib/msun/sparc64/fenv.h
View File

@ -1,262 +0,0 @@
/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2004-2005 David Schultz <das@FreeBSD.ORG>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#ifndef _FENV_H_
#define _FENV_H_
#include <sys/_types.h>
#ifndef __fenv_static
#define __fenv_static static
#endif
typedef __uint64_t fenv_t;
typedef __uint64_t fexcept_t;
/* Exception flags */
#define FE_INVALID 0x00000200
#define FE_DIVBYZERO 0x00000040
#define FE_OVERFLOW 0x00000100
#define FE_UNDERFLOW 0x00000080
#define FE_INEXACT 0x00000020
#define FE_ALL_EXCEPT (FE_DIVBYZERO | FE_INEXACT | \
FE_INVALID | FE_OVERFLOW | FE_UNDERFLOW)
/*
* Rounding modes
*
* We can't just use the hardware bit values here, because that would
* make FE_UPWARD and FE_DOWNWARD negative, which is not allowed.
*/
#define FE_TONEAREST 0x0
#define FE_TOWARDZERO 0x1
#define FE_UPWARD 0x2
#define FE_DOWNWARD 0x3
#define _ROUND_MASK (FE_TONEAREST | FE_DOWNWARD | \
FE_UPWARD | FE_TOWARDZERO)
#define _ROUND_SHIFT 30
__BEGIN_DECLS
/* Default floating-point environment */
extern const fenv_t __fe_dfl_env;
#define FE_DFL_ENV (&__fe_dfl_env)
/* We need to be able to map status flag positions to mask flag positions */
#define _FPUSW_SHIFT 18
#define _ENABLE_MASK (FE_ALL_EXCEPT << _FPUSW_SHIFT)
#define __ldxfsr(__r) __asm __volatile("ldx %0, %%fsr" : : "m" (__r))
#define __stxfsr(__r) __asm __volatile("stx %%fsr, %0" : "=m" (*(__r)))
__fenv_static __inline int
feclearexcept(int __excepts)
{
fexcept_t __r;
__stxfsr(&__r);
__r &= ~__excepts;
__ldxfsr(__r);
return (0);
}
__fenv_static inline int
fegetexceptflag(fexcept_t *__flagp, int __excepts)
{
fexcept_t __r;
__stxfsr(&__r);
*__flagp = __r & __excepts;
return (0);
}
__fenv_static inline int
fesetexceptflag(const fexcept_t *__flagp, int __excepts)
{
fexcept_t __r;
__stxfsr(&__r);
__r &= ~__excepts;
__r |= *__flagp & __excepts;
__ldxfsr(__r);
return (0);
}
/*
* It seems to be worthwhile to inline this function even when the
* arguments are not compile-time constants. Perhaps this depends
* on the register window.
*/
__fenv_static inline int
feraiseexcept(int __excepts)
{
volatile double d;
/*
* With a compiler that supports the FENV_ACCESS pragma
* properly, simple expressions like '0.0 / 0.0' should
* be sufficient to generate traps. Unfortunately, we
* need to bring a volatile variable into the equation
* to prevent incorrect optimizations.
*/
if (__excepts & FE_INVALID) {
d = 0.0;
d = 0.0 / d;
}
if (__excepts & FE_DIVBYZERO) {
d = 0.0;
d = 1.0 / d;
}
if (__excepts & FE_OVERFLOW) {
d = 0x1.ffp1023;
d *= 2.0;
}
if (__excepts & FE_UNDERFLOW) {
d = 0x1p-1022;
d /= 0x1p1023;
}
if (__excepts & FE_INEXACT) {
d = 0x1p-1022;
d += 1.0;
}
return (0);
}
__fenv_static inline int
fetestexcept(int __excepts)
{
fexcept_t __r;
__stxfsr(&__r);
return (__r & __excepts);
}
__fenv_static inline int
fegetround(void)
{
fenv_t __r;
__stxfsr(&__r);
return ((__r >> _ROUND_SHIFT) & _ROUND_MASK);
}
__fenv_static inline int
fesetround(int __round)
{
fenv_t __r;
if (__round & ~_ROUND_MASK)
return (-1);
__stxfsr(&__r);
__r &= ~(_ROUND_MASK << _ROUND_SHIFT);
__r |= __round << _ROUND_SHIFT;
__ldxfsr(__r);
return (0);
}
__fenv_static inline int
fegetenv(fenv_t *__envp)
{
__stxfsr(__envp);
return (0);
}
__fenv_static inline int
feholdexcept(fenv_t *__envp)
{
fenv_t __r;
__stxfsr(&__r);
*__envp = __r;
__r &= ~(FE_ALL_EXCEPT | _ENABLE_MASK);
__ldxfsr(__r);
return (0);
}
__fenv_static inline int
fesetenv(const fenv_t *__envp)
{
__ldxfsr(*__envp);
return (0);
}
__fenv_static inline int
feupdateenv(const fenv_t *__envp)
{
fexcept_t __r;
__stxfsr(&__r);
__ldxfsr(*__envp);
feraiseexcept(__r & FE_ALL_EXCEPT);
return (0);
}
#if __BSD_VISIBLE
/* We currently provide no external definitions of the functions below. */
static inline int
feenableexcept(int __mask)
{
fenv_t __old_r, __new_r;
__stxfsr(&__old_r);
__new_r = __old_r | ((__mask & FE_ALL_EXCEPT) << _FPUSW_SHIFT);
__ldxfsr(__new_r);
return ((__old_r >> _FPUSW_SHIFT) & FE_ALL_EXCEPT);
}
static inline int
fedisableexcept(int __mask)
{
fenv_t __old_r, __new_r;
__stxfsr(&__old_r);
__new_r = __old_r & ~((__mask & FE_ALL_EXCEPT) << _FPUSW_SHIFT);
__ldxfsr(__new_r);
return ((__old_r >> _FPUSW_SHIFT) & FE_ALL_EXCEPT);
}
static inline int
fegetexcept(void)
{
fenv_t __r;
__stxfsr(&__r);
return ((__r & _ENABLE_MASK) >> _FPUSW_SHIFT);
}
#endif /* __BSD_VISIBLE */
__END_DECLS
#endif /* !_FENV_H_ */