This is the mail archive of the
libc-alpha@sourceware.org
mailing list for the glibc project.
[PATCH v3 2/12] PPC64: Add libmvec SIMD single-precision cosine function.
- From: GT <tnggil at protonmail dot com>
- To: "libc-alpha\\@sourceware.org" <libc-alpha at sourceware dot org>
- Date: Wed, 03 Apr 2019 22:32:12 +0000
- Subject: [PATCH v3 2/12] PPC64: Add libmvec SIMD single-precision cosine function.
- Reply-to: GT <tnggil at protonmail dot com>
Differences from patch version v2:
1. Patch subject line prefix now has version id. The previous versions did not include
their version numbers so here are links to them:
v1: https://sourceware.org/ml/libc-alpha/2019-03/msg00053.html
v2: https://sourceware.org/ml/libc-alpha/2019-03/msg00128.html
2. Makefile adds -mabi=altivec and -maltivec flags for all libmvec targets to enable
successful builds in cases where GCC was not specifically configured for POWER8/9.
From bf203338480daf72207bb101dffcdf6f5a95e10e Mon Sep 17 00:00:00 2001
From: Bert Tenjy <bert.tenjy@gmail.com>
Date: Thu, 7 Mar 2019 05:17:47 +0000
Subject: [PATCH v3 2/12] PPC64: Add libmvec SIMD single-precision cosine
function.
[BZ #24205]
Implements single-precision cosine using VSX vector capability. The polynomial
cosine-approximating algorithm is adapted for PPC64 from x86_64 [commit #04f496d602].
The patch has been tested on PPC64/POWER8 Little Endian and Big Endian. It is
tested using the framework created for libmvec on x86_64 which runs tests on
issuing 'make check'. Tests of the new vector cosine function all pass.
Details on the ABI are found at this link:
<https://sourceware.org/glibc/wiki/
libmvec?action=AttachFile&do=view&target=VectorABI.txt>
But for adjusting the width of operands, details described for the
double-precision cosine implemented earlier apply here. See git
commit #7956c29f07 for that information.
---
ChangeLog | 15 +++
NEWS | 10 +-
sysdeps/powerpc/fpu/libm-test-ulps | 3 +
sysdeps/powerpc/powerpc64/fpu/Versions | 2 +-
.../powerpc/powerpc64/fpu/multiarch/Makefile | 10 +-
.../fpu/multiarch/test-float-vlen4-wrappers.c | 24 ++++
.../powerpc64/fpu/multiarch/vec_s_cosf4_vsx.c | 109 ++++++++++++++++++
.../powerpc64/fpu/multiarch/vec_s_trig_data.h | 72 ++++++++++++
.../linux/powerpc/powerpc64/libmvec.abilist | 1 +
9 files changed, 241 insertions(+), 5 deletions(-)
create mode 100644 sysdeps/powerpc/powerpc64/fpu/multiarch/test-float-vlen4-wrappers.c
create mode 100644 sysdeps/powerpc/powerpc64/fpu/multiarch/vec_s_cosf4_vsx.c
create mode 100644 sysdeps/powerpc/powerpc64/fpu/multiarch/vec_s_trig_data.h
diff --git a/ChangeLog b/ChangeLog
index efe4253f6d..1d6636b8fb 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,18 @@
+2019-04-03 Bert Tenjy <bert.tenjy@gmail.com>
+
+ [BZ #24205]
+ * NEWS: Note the addition of PPC64 vector cosf.
+ * sysdeps/powerpc/fpu/libm-test-ulps: Regenerated.
+ * sysdeps/powerpc/powerpc64/fpu/Versions: Added new cosf entry.
+ * sysdeps/powerpc/powerpc64/fpu/multiarch/Makefile: (libmvec-sysdep_routines)
+ (CFLAGS-vec_s_cosf4_vsx.c, libmvec-tests, float-vlen4-funcs)
+ (float-vlen4-arch-ext-cflags): Added build of VSX SIMD cosf function
+ and its tests.
+ * sysdeps/powerpc/powerpc64/fpu/multiarch/test-float-vlen4-wrappers.c: New file.
+ * sysdeps/powerpc/powerpc64/fpu/multiarch/vec_s_cosf4_vsx.c: New file.
+ * sysdeps/powerpc/powerpc64/fpu/multiarch/vec_s_trig_data.h: Likewise.
+ * sysdeps/unix/sysv/linux/powerpc/powerpc64/libmvec.abilist: New SIMD cosf added.
+
2019-04-03 Bert Tenjy <bert.tenjy@gmail.com>
[BZ #24205]
diff --git a/NEWS b/NEWS
index 22735e1d1d..183b306f75 100644
--- a/NEWS
+++ b/NEWS
@@ -10,13 +10,19 @@ Version 2.30
Major new features:
-* Start of implementing vector math library libmvec on PPC64/POWER8.
- The double-precision cosine now has a vector version.
+* Implementation of vector math library libmvec on PPC64/POWER8.
+
+ The following functions now have vector versions.
+ - double-precision cosine: cos
+ - single-precision cosine: cosf
+
GCC support for auto-vectorization of functions on PPC64 is not yet
available. Until that is done, the new vector math functions are
inaccessible to applications.
+
Library libmvec is built by default for PPC64. Disable its creation by
passing flag --disable-mathvec to configure.
+
The library ABI specification is x86_64 Vector Function ABI.
More information on libmvec including a link to the ABI document is at:
<https://sourceware.org/glibc/wiki/libmvec>
diff --git a/sysdeps/powerpc/fpu/libm-test-ulps b/sysdeps/powerpc/fpu/libm-test-ulps
index d392b135a7..3bd9e67096 100644
--- a/sysdeps/powerpc/fpu/libm-test-ulps
+++ b/sysdeps/powerpc/fpu/libm-test-ulps
@@ -1314,6 +1314,9 @@ ldouble: 5
Function: "cos_vlen2":
double: 2
+Function: "cos_vlen4":
+float: 1
+
Function: "cosh":
double: 1
float: 1
diff --git a/sysdeps/powerpc/powerpc64/fpu/Versions b/sysdeps/powerpc/powerpc64/fpu/Versions
index 9a3e1211cc..bdd4b657c4 100644
--- a/sysdeps/powerpc/powerpc64/fpu/Versions
+++ b/sysdeps/powerpc/powerpc64/fpu/Versions
@@ -1,5 +1,5 @@
libmvec {
GLIBC_2.30 {
- _ZGVbN2v_cos;
+ _ZGVbN2v_cos; _ZGVbN4v_cosf;
}
}
diff --git a/sysdeps/powerpc/powerpc64/fpu/multiarch/Makefile b/sysdeps/powerpc/powerpc64/fpu/multiarch/Makefile
index d713b61431..ad9d8f0127 100644
--- a/sysdeps/powerpc/powerpc64/fpu/multiarch/Makefile
+++ b/sysdeps/powerpc/powerpc64/fpu/multiarch/Makefile
@@ -44,18 +44,24 @@ CFLAGS-s_modff-ppc64.c += -fsignaling-nans
endif
ifeq ($(subdir),mathvec)
-libmvec-sysdep_routines += vec_d_cos2_vsx
+libmvec-sysdep_routines += vec_d_cos2_vsx vec_s_cosf4_vsx
CFLAGS-vec_d_cos2_vsx.c += -mabi=altivec -maltivec -mvsx
+CFLAGS-vec_s_cosf4_vsx.c += -mabi=altivec -maltivec -mvsx
endif
# Variables for libmvec tests.
ifeq ($(subdir),math)
ifeq ($(build-mathvec),yes)
-libmvec-tests += double-vlen2
+libmvec-tests += double-vlen2 float-vlen4
double-vlen2-funcs = cos
+float-vlen4-funcs = cos
double-vlen2-arch-ext-cflags = -mabi=altivec -maltivec -mvsx -DREQUIRE_VSX
+float-vlen4-arch-ext-cflags = -mabi=altivec -maltivec -mvsx -DREQUIRE_VSX
+
CFLAGS-test-double-vlen2-wrappers.c += -mabi=altivec -maltivec -mvsx -DREQUIRE_VSX
+CFLAGS-test-float-vlen4-wrappers.c += -mabi=altivec -maltivec -mvsx -DREQUIRE_VSX
+
endif
endif
diff --git a/sysdeps/powerpc/powerpc64/fpu/multiarch/test-float-vlen4-wrappers.c b/sysdeps/powerpc/powerpc64/fpu/multiarch/test-float-vlen4-wrappers.c
new file mode 100644
index 0000000000..f099990d4e
--- /dev/null
+++ b/sysdeps/powerpc/powerpc64/fpu/multiarch/test-float-vlen4-wrappers.c
@@ -0,0 +1,24 @@
+/* Wrapper part of tests for VSX ISA versions of vector math functions.
+ Copyright (C) 2019 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#include "test-float-vlen4.h"
+#include <altivec.h>
+
+#define VEC_TYPE vector float
+
+VECTOR_WRAPPER (WRAPPER_NAME (cosf), _ZGVbN4v_cosf)
diff --git a/sysdeps/powerpc/powerpc64/fpu/multiarch/vec_s_cosf4_vsx.c b/sysdeps/powerpc/powerpc64/fpu/multiarch/vec_s_cosf4_vsx.c
new file mode 100644
index 0000000000..fb9d27b865
--- /dev/null
+++ b/sysdeps/powerpc/powerpc64/fpu/multiarch/vec_s_cosf4_vsx.c
@@ -0,0 +1,109 @@
+/* Function cosf vectorized with VSX.
+ Copyright (C) 2019 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#include <math.h>
+#include "vec_s_trig_data.h"
+
+vector float
+_ZGVbN4v_cosf (vector float x)
+{
+
+ /*
+ ALGORITHM DESCRIPTION:
+
+ 1) Range reduction to [-Pi/2; +Pi/2] interval
+ a) We remove sign using absolute value operation
+ b) Add Pi/2 value to argument X for Cos to Sin transformation
+ c) Getting octant Y by 1/Pi multiplication
+ d) Add "Right Shifter" value
+ e) Treat obtained value as integer for destination sign setting.
+ Shift first bit of this value to the last (sign) position
+ f) Subtract "Right Shifter" value
+ g) Subtract 0.5 from result for octant correction
+ h) Subtract Y*PI from X argument, where PI divided to 4 parts:
+ X = X - Y*PI1 - Y*PI2 - Y*PI3 - Y*PI4;
+ 2) Polynomial (minimax for sin within [-Pi/2; +Pi/2] interval)
+ a) Calculate X^2 = X * X
+ b) Calculate polynomial:
+ R = X + X * X^2 * (A3 + x^2 * (A5 + .....
+ 3) Destination sign setting
+ a) Set shifted destination sign using XOR operation:
+ R = XOR( R, S ). */
+
+ /*
+ ARGUMENT RANGE REDUCTION:
+ Add Pi/2 to argument: X' = X+Pi/2. Transforms cos to sin. */
+ vector float x_prime = __s_half_pi + x;
+
+ /* Y = X'*InvPi + RS : right shifter add. */
+ vector float y = (x_prime * __s_inv_pi) + __s_rshifter;
+
+ /* N = Y - RS : right shifter sub. */
+ vector float n = y - __s_rshifter;
+
+ /* SignRes = Y<<31 : shift LSB to MSB place for result sign. */
+ vector float sign_res = (vector float)
+ vec_sl ((vector signed int) y, (vector unsigned int) vec_splats (31));
+
+ /* N = N - 0.5. */
+ n = n - __s_one_half;
+
+ /* Get absolute argument value: X = |X|. */
+ vector float abs_x = vec_abs (x);
+
+ /* Check for large arguments path. */
+ vector bool int large_in = vec_cmpgt (abs_x, __s_rangeval);
+
+ /* R = X - N*Pi1. */
+ vector float r = x - (n * __s_pi1_fma);
+
+ /* R = R - N*Pi2. */
+ r = r - (n * __s_pi2_fma);
+
+ /* R = R - N*Pi3. */
+ r = r - (n * __s_pi3_fma);
+
+ /* R2 = R*R. */
+ vector float r2 = r * r;
+
+ /* RECONSTRUCTION:
+ Final sign setting: Res = Poly^SignRes. */
+ vector float res = (vector float)
+ ((vector signed int) r ^ (vector signed int) sign_res);
+
+ /* Poly = R + R * R2*(A3+R2*(A5+R2*(A7+R2*A9))). */
+ vector float poly = r2 * __s_a9_fma + __s_a7_fma;
+ poly = poly * r2 + __s_a5_fma;
+ poly = poly * r2 + __s_a3;
+ poly = poly * r2 * res + res;
+
+ if (large_in[0])
+ poly[0] = cosf (x[0]);
+
+ if (large_in[1])
+ poly[1] = cosf (x[1]);
+
+ if (large_in[2])
+ poly[2] = cosf (x[2]);
+
+ if (large_in[3])
+ poly[3] = cosf (x[3]);
+
+ return poly;
+
+} /* Function _ZGVbN4v_cosf. */
diff --git a/sysdeps/powerpc/powerpc64/fpu/multiarch/vec_s_trig_data.h b/sysdeps/powerpc/powerpc64/fpu/multiarch/vec_s_trig_data.h
new file mode 100644
index 0000000000..55c28563e7
--- /dev/null
+++ b/sysdeps/powerpc/powerpc64/fpu/multiarch/vec_s_trig_data.h
@@ -0,0 +1,72 @@
+/* Constants used in polynomial approximations for vectorized sinf, cosf,
+ and sincosf functions.
+ Copyright (C) 2019 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#ifndef S_TRIG_DATA_H
+#define S_TRIG_DATA_H
+
+#include <altivec.h>
+
+/* PI/2. */
+const vector float __s_half_pi =
+{ 0x1.921fb6p+0, 0x1.921fb6p+0, 0x1.921fb6p+0, 0x1.921fb6p+0 };
+
+/* Inverse PI. */
+const vector float __s_inv_pi =
+{ 0x1.45f306p-2, 0x1.45f306p-2, 0x1.45f306p-2, 0x1.45f306p-2 };
+
+/* Right-shifter constant. */
+const vector float __s_rshifter =
+{ 0x1.8p+23, 0x1.8p+23, 0x1.8p+23, 0x1.8p+23 };
+
+/* One-half. */
+const vector float __s_one_half =
+{ 0x1p-1, 0x1p-1, 0x1p-1, 0x1p-1 };
+
+/* Threshold for out-of-range values. */
+const vector float __s_rangeval =
+{ 0x1.388p+13, 0x1.388p+13, 0x1.388p+13, 0x1.388p+13 };
+
+/* PI1, PI2, and PI3 when FMA is available
+ PI high part (when FMA available). */
+const vector float __s_pi1_fma =
+{ 0x1.921fb6p+1, 0x1.921fb6p+1, 0x1.921fb6p+1, 0x1.921fb6p+1 };
+
+/* PI mid part (when FMA available). */
+const vector float __s_pi2_fma =
+{ -0x1.777a5cp-24, -0x1.777a5cp-24, -0x1.777a5cp-24, -0x1.777a5cp-24 };
+
+/* PI low part (when FMA available). */
+const vector float __s_pi3_fma =
+{ -0x1.ee59dap-49, -0x1.ee59dap-49, -0x1.ee59dap-49, -0x1.ee59dap-49 };
+
+/* Polynomial constants for work w/o FMA, relative error ~ 2^(-26.625). */
+const vector float __s_a3 =
+{ -0x1.55554cp-3, -0x1.55554cp-3, -0x1.55554cp-3, -0x1.55554cp-3 };
+
+/* Polynomial constants, work with FMA, relative error ~ 2^(-26.417). */
+const vector float __s_a5_fma =
+{ 0x1.110edp-7, 0x1.110edp-7, 0x1.110edp-7, 0x1.110edp-7 };
+
+const vector float __s_a7_fma =
+{ -0x1.9f6d9ep-13, -0x1.9f6d9ep-13, -0x1.9f6d9ep-13, -0x1.9f6d9ep-13 };
+
+const vector float __s_a9_fma =
+{ 0x1.5d866ap-19, 0x1.5d866ap-19, 0x1.5d866ap-19, 0x1.5d866ap-19 };
+
+#endif /* S_TRIG_DATA_H. */
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libmvec.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libmvec.abilist
index 656ce0541f..8eef5e1e72 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libmvec.abilist
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libmvec.abilist
@@ -1 +1,2 @@
GLIBC_2.30 _ZGVbN2v_cos F
+GLIBC_2.30 _ZGVbN4v_cosf F
--
2.20.1