math: Use log10f from CORE-MATH

The CORE-MATH implementation is correctly rounded (for any rounding mode)
and shows better performance compared to the generic log10f.

The code was adapted to glibc style and to use the definition of
math_config.h (to handle errno, overflow, and underflow).

Benchtest on x64_64 (Ryzen 9 5900X, gcc 14.2.1), aarch64 (Neoverse-N1,
gcc 13.3.1), and powerpc (POWER10, gcc 13.2.1):

Latency                      master        patched   improvement
x86_64                      49.9017        33.5143        32.84%
x86_64v2                    50.4878        33.5623        33.52%
x86_64v3                    50.0991        27.6078        44.89%
i686                        140.874        106.086        24.69%
aarch64                     19.2846        11.3573        41.11%
power10                     14.0994        7.7739        44.86%
powerpc                     14.2898        7.92497        44.54%

reciprocal-throughput        master        patched   improvement
x86_64                      17.8336        12.9074        27.62%
x86_64v2                    16.4418        11.3220        31.14%
x86_64v3                    15.6002        10.5158        32.59%
i686                        66.0678        80.2287        -21.43%
aarch64                      9.4906        6.8393        27.94%
power10                      7.5255        5.5084        26.80%
powerpc                      9.5204        6.98055        26.68%

The performance decrease for i686 is mostly due the use of x87 fpu,
when building with '-msse2 -mfpmath=sse':

                             master        patched   improvement
latency                     140.874        77.1137        45.26%
reciprocal-throughput        64.481        56.4397        12.47%

Signed-off-by: Alexei Sibidanov <sibid@uvic.ca>
Signed-off-by: Paul Zimmermann <Paul.Zimmermann@inria.fr>
Signed-off-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Reviewed-by: DJ Delorie <dj@redhat.com>
This commit is contained in:
Adhemerval Zanella 2024-10-21 15:51:27 -03:00
parent bbd578b38d
commit 9247f53219
3 changed files with 154 additions and 108 deletions

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@ -252,3 +252,7 @@ sysdeps/ieee754/flt-32/s_expm1f.c
(file src/binary32/expm1/expm1f.c in CORE-MATH) (file src/binary32/expm1/expm1f.c in CORE-MATH)
- The code was adapted to use glibc code style and internal - The code was adapted to use glibc code style and internal
functions to handle errno, overflow, and underflow. functions to handle errno, overflow, and underflow.
sysdeps/ieee754/flt-32/e_log10f.c
(file src/binary32/log10/log10f.c in CORE-MATH)
- The code was adapted to use glibc code style and internal
functions to handle errno, overflow, and underflow.

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@ -1,66 +0,0 @@
/*
* Public domain.
*/
#include <machine/asm.h>
#include <libm-alias-finite.h>
.section .rodata.cst8,"aM",@progbits,8
.p2align 3
.type one,@object
one: .double 1.0
ASM_SIZE_DIRECTIVE(one)
/* It is not important that this constant is precise. It is only
a value which is known to be on the safe side for using the
fyl2xp1 instruction. */
.type limit,@object
limit: .double 0.29
ASM_SIZE_DIRECTIVE(limit)
#ifdef PIC
# define MO(op) op##@GOTOFF(%edx)
#else
# define MO(op) op
#endif
.text
ENTRY(__ieee754_log10f)
fldlg2 // log10(2)
flds 4(%esp) // x : log10(2)
#ifdef PIC
LOAD_PIC_REG (dx)
#endif
fxam
fnstsw
fld %st // x : x : log10(2)
sahf
jc 3f // in case x is NaN or ±Inf
4: fsubl MO(one) // x-1 : x : log10(2)
fld %st // x-1 : x-1 : x : log10(2)
fabs // |x-1| : x-1 : x : log10(2)
fcompl MO(limit) // x-1 : x : log10(2)
fnstsw // x-1 : x : log10(2)
andb $0x45, %ah
jz 2f
fxam
fnstsw
andb $0x45, %ah
cmpb $0x40, %ah
jne 5f
fabs // log10(1) is +0 in all rounding modes.
5: fstp %st(1) // x-1 : log10(2)
fyl2xp1 // log10(x)
ret
2: fstp %st(0) // x : log10(2)
fyl2x // log10(x)
ret
3: jp 4b // in case x is ±Inf
fstp %st(1)
fstp %st(1)
ret
END (__ieee754_log10f)
libm_alias_finite (__ieee754_log10f, __log10f)

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@ -1,54 +1,162 @@
/* e_log10f.c -- float version of e_log10.c. /* Correctly-rounded radix-10 logarithm function for binary32 value.
*/
/* Copyright (c) 2022-2023 Alexei Sibidanov.
* ====================================================
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. This file is part of the CORE-MATH project
* project (file src/binary32/log10/log10f.c, revision bc385c2).
* Developed at SunPro, a Sun Microsystems, Inc. business.
* Permission to use, copy, modify, and distribute this Permission is hereby granted, free of charge, to any person obtaining a copy
* software is freely granted, provided that this notice of this software and associated documentation files (the "Software"), to deal
* is preserved. in the Software without restriction, including without limitation the rights
* ==================================================== to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
*/ */
#include <math.h> #include <math.h>
#include <math_private.h> #include <stdint.h>
#include <fix-int-fp-convert-zero.h>
#include <libm-alias-finite.h> #include <libm-alias-finite.h>
#include "math_config.h"
static const float static __attribute__ ((noinline)) float
two25 = 3.3554432000e+07, /* 0x4c000000 */ as_special (float x)
ivln10 = 4.3429449201e-01, /* 0x3ede5bd9 */ {
log10_2hi = 3.0102920532e-01, /* 0x3e9a2080 */ uint32_t ux = asuint (x);
log10_2lo = 7.9034151668e-07; /* 0x355427db */ if (ux == 0x7f800000u)
return x; /* +inf */
uint32_t ax = ux << 1;
if (ax == 0u)
{ /* -0.0 */
__math_divzerof (1);
}
if (ax > 0xff000000u)
return x + x; /* nan */
return __math_invalidf (x);
}
float float
__ieee754_log10f (float x) __ieee754_log10f (float x)
{ {
float y,z; static const double tr[] =
int32_t i,k,hx; {
0x1p+0, 0x1.f81f82p-1, 0x1.f07c1fp-1, 0x1.e9131acp-1,
GET_FLOAT_WORD(hx,x); 0x1.e1e1e1ep-1, 0x1.dae6077p-1, 0x1.d41d41dp-1, 0x1.cd85689p-1,
0x1.c71c71cp-1, 0x1.c0e0704p-1, 0x1.bacf915p-1, 0x1.b4e81b5p-1,
k=0; 0x1.af286bdp-1, 0x1.a98ef6p-1, 0x1.a41a41ap-1, 0x1.9ec8e95p-1,
if (hx < 0x00800000) { /* x < 2**-126 */ 0x1.999999ap-1, 0x1.948b0fdp-1, 0x1.8f9c19p-1, 0x1.8acb90fp-1,
if (__builtin_expect((hx&0x7fffffff)==0, 0)) 0x1.8618618p-1, 0x1.8181818p-1, 0x1.7d05f41p-1, 0x1.78a4c81p-1,
return -two25/fabsf (x); /* log(+-0)=-inf */ 0x1.745d174p-1, 0x1.702e05cp-1, 0x1.6c16c17p-1, 0x1.6816817p-1,
if (__builtin_expect(hx<0, 0)) 0x1.642c859p-1, 0x1.605816p-1, 0x1.5c9882cp-1, 0x1.58ed231p-1,
return (x-x)/(x-x); /* log(-#) = NaN */ 0x1.5555555p-1, 0x1.51d07ebp-1, 0x1.4e5e0a7p-1, 0x1.4afd6ap-1,
k -= 25; x *= two25; /* subnormal number, scale up x */ 0x1.47ae148p-1, 0x1.446f865p-1, 0x1.4141414p-1, 0x1.3e22cbdp-1,
GET_FLOAT_WORD(hx,x); 0x1.3b13b14p-1, 0x1.3813814p-1, 0x1.3521cfbp-1, 0x1.323e34ap-1,
0x1.2f684bep-1, 0x1.2c9fb4ep-1, 0x1.29e412ap-1, 0x1.27350b9p-1,
0x1.2492492p-1, 0x1.21fb781p-1, 0x1.1f7047ep-1, 0x1.1cf06aep-1,
0x1.1a7b961p-1, 0x1.1811812p-1, 0x1.15b1e5fp-1, 0x1.135c811p-1,
0x1.1111111p-1, 0x1.0ecf56cp-1, 0x1.0c9715p-1, 0x1.0a6810ap-1,
0x1.0842108p-1, 0x1.0624dd3p-1, 0x1.041041p-1, 0x1.0204081p-1,
0.5
};
static const double tl[] =
{
-0x1.d45fd6237ebe3p-47, 0x1.b947689311b6ep-8, 0x1.b5e909c96d7d5p-7,
0x1.45f4f59ed2165p-6, 0x1.af5f92cbd8f1ep-6, 0x1.0ba01a606de8cp-5,
0x1.3ed119b9a2b7bp-5, 0x1.714834298eec2p-5, 0x1.a30a9d98357fbp-5,
0x1.d41d512670813p-5, 0x1.02428c0f65519p-4, 0x1.1a23444eecc3ep-4,
0x1.31b30543f4cb4p-4, 0x1.48f3ed39bfd04p-4, 0x1.5fe8049a0e423p-4,
0x1.769140a6aa008p-4, 0x1.8cf1836c98cb3p-4, 0x1.a30a9d55541a1p-4,
0x1.b8de4d1ee823ep-4, 0x1.ce6e4202ca2e6p-4, 0x1.e3bc1accace07p-4,
0x1.f8c9683b5abd4p-4, 0x1.06cbd68ca9a6ep-3, 0x1.11142f19df73p-3,
0x1.1b3e71fa7a97fp-3, 0x1.254b4d37a46e3p-3, 0x1.2f3b6912cbf07p-3,
0x1.390f683115886p-3, 0x1.42c7e7fffc5a8p-3, 0x1.4c65808c78d3cp-3,
0x1.55e8c50751c55p-3, 0x1.5f52445dec3d8p-3, 0x1.68a288c3f12p-3,
0x1.71da17bdf0d19p-3, 0x1.7af973608afd9p-3, 0x1.84011952a2579p-3,
0x1.8cf1837a7ea6p-3, 0x1.95cb2891e43d6p-3, 0x1.9e8e7b0f869ep-3,
0x1.a73beaa5db18dp-3, 0x1.afd3e394558d3p-3, 0x1.b856cf060d9f1p-3,
0x1.c0c5134de1ffcp-3, 0x1.c91f1371bc99fp-3, 0x1.d1652ffcd3f53p-3,
0x1.d997c6f635e75p-3, 0x1.e1b733ab90f3bp-3, 0x1.e9c3ceadac856p-3,
0x1.f1bdeec43a305p-3, 0x1.f9a5e7a5fa3fep-3, 0x1.00be05ac02f2bp-2,
0x1.04a054d81a2d4p-2, 0x1.087a0835957fbp-2, 0x1.0c4b457099517p-2,
0x1.101431aa1fe51p-2, 0x1.13d4f08b98dd8p-2, 0x1.178da53edb892p-2,
0x1.1b3e71e9f9d58p-2, 0x1.1ee777defdeedp-2, 0x1.2288d7b48e23bp-2,
0x1.2622b0f52e49fp-2, 0x1.29b522a4c6314p-2, 0x1.2d404b0e30f8p-2,
0x1.30c4478f3fbe5p-2, 0x1.34413509f7915p-2
};
static const union
{
float f;
uint32_t u;
} st[] =
{
{ 0x1p+0 }, { 0x1.4p+3 }, { 0x1.9p+6 }, { 0x1.f4p+9 },
{ 0x1.388p+13 }, { 0x1.86ap+16 }, { 0x1.e848p+19 }, { 0x1.312dp+23 },
{ 0x1.7d784p+26 }, { 0x1.dcd65p+29 }, { 0x1.2a05f2p+33 }, { 0 },
{ 0 }, { 0 }, { 0 }, { 0 }
};
static const double b[] =
{
0x1.bcb7b15c5a2f8p-2, -0x1.bcbb1dbb88ebap-3, 0x1.2871c39d521c6p-3
};
static const double c[] =
{
0x1.bcb7b1526e50ep-2, -0x1.bcb7b1526e53dp-3, 0x1.287a7636f3fa2p-3,
-0x1.bcb7b146a14b3p-4, 0x1.63c627d5219cbp-4, -0x1.2880736c8762dp-4,
0x1.fc1ecf913961ap-5
};
uint32_t ux = asuint (x);
if (__glibc_unlikely (ux < (1 << 23) || ux >= 0x7f800000u))
{
if (ux == 0 || ux >= 0x7f800000u)
return as_special (x);
/* subnormal */
int n = __builtin_clz (ux) - 8;
ux <<= n;
ux -= n << 23;
} }
if (__builtin_expect(hx >= 0x7f800000, 0)) return x+x; unsigned m = ux & ((1 << 23) - 1), j = (m + (1 << (23 - 7))) >> (23 - 6);
k += (hx>>23)-127; double ix = tr[j], l = tl[j];
i = ((uint32_t)k&0x80000000)>>31; int e = ((int) ux >> 23) - 127;
hx = (hx&0x007fffff)|((0x7f-i)<<23); unsigned je = e + 1;
y = (float)(k+i); je = (je * 0x4d104d4) >> 28;
if (FIX_INT_FP_CONVERT_ZERO && y == 0.0f) if (__glibc_unlikely (ux == st[je].u))
y = 0.0f; return je;
SET_FLOAT_WORD(x,hx);
z = y*log10_2lo + ivln10*__ieee754_logf(x); double tz = asdouble (((int64_t) m | ((int64_t) 1023 << 23)) << (52 - 23));
return z+y*log10_2hi; double z = tz * ix - 1, z2 = z * z;
double r
= ((e * 0x1.34413509f79ffp-2 + l) + z * b[0]) + z2 * (b[1] + z * b[2]);
float ub = r, lb = r + 0x1.b008p-34;
if (__glibc_unlikely (ub != lb))
{
double f = z
* ((c[0] + z * c[1])
+ z2
* ((c[2] + z * c[3])
+ z2 * (c[4] + z * c[5] + z2 * c[6])));
f -= 0x1.0cee0ed4ca7e9p-54 * e;
f += l - tl[0];
double el = e * 0x1.34413509f7ap-2;
r = el + f;
ub = r;
tz = r;
if (__glibc_unlikely (!((asuint64 (tz) & ((1 << 28) - 1)))))
{
double dr = (el - r) + f;
r += dr * 32;
ub = r;
}
}
return ub;
} }
libm_alias_finite (__ieee754_log10f, __log10f) libm_alias_finite (__ieee754_log10f, __log10f)