x86-64: Add vector log2/log2f implementation to libmvec

Implement vectorized log2/log2f containing SSE, AVX, AVX2 and
AVX512 versions for libmvec as per vector ABI.  It also contains
accuracy and ABI tests for vector log2/log2f with regenerated ulps.

Reviewed-by: H.J. Lu <hjl.tools@gmail.com>

1 files changed, 231 insertions, 0 deletions

diff --git a/sysdeps/x86_64/fpu/multiarch/svml_s_log2f16_core_avx512.S b/sysdeps/x86_64/fpu/multiarch/svml_s_log2f16_core_avx512.S
new file mode 100644
index 0000000000..c3a5aceef4
--- /dev/null
+++ b/sysdeps/x86_64/fpu/multiarch/svml_s_log2f16_core_avx512.S
@@ -0,0 +1,231 @@
+/* Function log2f vectorized with AVX-512.
+   Copyright (C) 2021 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
+   https://www.gnu.org/licenses/.  */
+
+/*
+ * ALGORITHM DESCRIPTION:
+ *
+ *    Get short reciprocal approximation Rcp ~ 1/mantissa(x)
+ *    R = Rcp*x - 1.0
+ *    log2(x) = k - log2(Rcp) + poly_approximation(R)
+ *       log2(Rcp) is tabulated
+ *
+ *
+ */
+
+/* Offsets for data table __svml_slog2_data_internal_avx512
+ */
+#define One                           	0
+#define coeff4                        	64
+#define coeff3                        	128
+#define coeff2                        	192
+#define coeff1                        	256
+
+#include <sysdep.h>
+
+        .text
+	.section .text.exex512,"ax",@progbits
+ENTRY(_ZGVeN16v_log2f_skx)
+        pushq     %rbp
+        cfi_def_cfa_offset(16)
+        movq      %rsp, %rbp
+        cfi_def_cfa(6, 16)
+        cfi_offset(6, -16)
+        andq      $-64, %rsp
+        subq      $192, %rsp
+        vgetmantps $11, {sae}, %zmm0, %zmm3
+        vmovups   __svml_slog2_data_internal_avx512(%rip), %zmm1
+        vgetexpps {sae}, %zmm0, %zmm5
+
+/* x<=0? */
+        vfpclassps $94, %zmm0, %k0
+        vsubps    {rn-sae}, %zmm1, %zmm3, %zmm9
+        vpsrld    $19, %zmm3, %zmm7
+        vgetexpps {sae}, %zmm3, %zmm6
+        vpermps   coeff4+__svml_slog2_data_internal_avx512(%rip), %zmm7, %zmm1
+        vpermps   coeff3+__svml_slog2_data_internal_avx512(%rip), %zmm7, %zmm2
+        vpermps   coeff2+__svml_slog2_data_internal_avx512(%rip), %zmm7, %zmm4
+        vpermps   coeff1+__svml_slog2_data_internal_avx512(%rip), %zmm7, %zmm8
+        vsubps    {rn-sae}, %zmm6, %zmm5, %zmm10
+        vfmadd213ps {rn-sae}, %zmm2, %zmm9, %zmm1
+        kmovw     %k0, %edx
+        vfmadd213ps {rn-sae}, %zmm4, %zmm9, %zmm1
+        vfmadd213ps {rn-sae}, %zmm8, %zmm9, %zmm1
+        vfmadd213ps {rn-sae}, %zmm10, %zmm9, %zmm1
+        testl     %edx, %edx
+
+/* Go to special inputs processing branch */
+        jne       L(SPECIAL_VALUES_BRANCH)
+                                # LOE rbx r12 r13 r14 r15 edx zmm0 zmm1
+
+/* Restore registers
+ * and exit the function
+ */
+
+L(EXIT):
+        vmovaps   %zmm1, %zmm0
+        movq      %rbp, %rsp
+        popq      %rbp
+        cfi_def_cfa(7, 8)
+        cfi_restore(6)
+        ret
+        cfi_def_cfa(6, 16)
+        cfi_offset(6, -16)
+
+/* Branch to process
+ * special inputs
+ */
+
+L(SPECIAL_VALUES_BRANCH):
+        vmovups   %zmm0, 64(%rsp)
+        vmovups   %zmm1, 128(%rsp)
+                                # LOE rbx r12 r13 r14 r15 edx zmm1
+
+        xorl      %eax, %eax
+                                # LOE rbx r12 r13 r14 r15 eax edx
+
+        vzeroupper
+        movq      %r12, 16(%rsp)
+        /*  DW_CFA_expression: r12 (r12) (DW_OP_lit8; DW_OP_minus; DW_OP_const4s: -64; DW_OP_and; DW_OP_const4s: -176; DW_OP_plus)  */
+        .cfi_escape 0x10, 0x0c, 0x0e, 0x38, 0x1c, 0x0d, 0xc0, 0xff, 0xff, 0xff, 0x1a, 0x0d, 0x50, 0xff, 0xff, 0xff, 0x22
+        movl      %eax, %r12d
+        movq      %r13, 8(%rsp)
+        /*  DW_CFA_expression: r13 (r13) (DW_OP_lit8; DW_OP_minus; DW_OP_const4s: -64; DW_OP_and; DW_OP_const4s: -184; DW_OP_plus)  */
+        .cfi_escape 0x10, 0x0d, 0x0e, 0x38, 0x1c, 0x0d, 0xc0, 0xff, 0xff, 0xff, 0x1a, 0x0d, 0x48, 0xff, 0xff, 0xff, 0x22
+        movl      %edx, %r13d
+        movq      %r14, (%rsp)
+        /*  DW_CFA_expression: r14 (r14) (DW_OP_lit8; DW_OP_minus; DW_OP_const4s: -64; DW_OP_and; DW_OP_const4s: -192; DW_OP_plus)  */
+        .cfi_escape 0x10, 0x0e, 0x0e, 0x38, 0x1c, 0x0d, 0xc0, 0xff, 0xff, 0xff, 0x1a, 0x0d, 0x40, 0xff, 0xff, 0xff, 0x22
+                                # LOE rbx r15 r12d r13d
+
+/* Range mask
+ * bits check
+ */
+
+L(RANGEMASK_CHECK):
+        btl       %r12d, %r13d
+
+/* Call scalar math function */
+        jc        L(SCALAR_MATH_CALL)
+                                # LOE rbx r15 r12d r13d
+
+/* Special inputs
+ * processing loop
+ */
+
+L(SPECIAL_VALUES_LOOP):
+        incl      %r12d
+        cmpl      $16, %r12d
+
+/* Check bits in range mask */
+        jl        L(RANGEMASK_CHECK)
+                                # LOE rbx r15 r12d r13d
+
+        movq      16(%rsp), %r12
+        cfi_restore(12)
+        movq      8(%rsp), %r13
+        cfi_restore(13)
+        movq      (%rsp), %r14
+        cfi_restore(14)
+        vmovups   128(%rsp), %zmm1
+
+/* Go to exit */
+        jmp       L(EXIT)
+        /*  DW_CFA_expression: r12 (r12) (DW_OP_lit8; DW_OP_minus; DW_OP_const4s: -64; DW_OP_and; DW_OP_const4s: -176; DW_OP_plus)  */
+        .cfi_escape 0x10, 0x0c, 0x0e, 0x38, 0x1c, 0x0d, 0xc0, 0xff, 0xff, 0xff, 0x1a, 0x0d, 0x50, 0xff, 0xff, 0xff, 0x22
+        /*  DW_CFA_expression: r13 (r13) (DW_OP_lit8; DW_OP_minus; DW_OP_const4s: -64; DW_OP_and; DW_OP_const4s: -184; DW_OP_plus)  */
+        .cfi_escape 0x10, 0x0d, 0x0e, 0x38, 0x1c, 0x0d, 0xc0, 0xff, 0xff, 0xff, 0x1a, 0x0d, 0x48, 0xff, 0xff, 0xff, 0x22
+        /*  DW_CFA_expression: r14 (r14) (DW_OP_lit8; DW_OP_minus; DW_OP_const4s: -64; DW_OP_and; DW_OP_const4s: -192; DW_OP_plus)  */
+        .cfi_escape 0x10, 0x0e, 0x0e, 0x38, 0x1c, 0x0d, 0xc0, 0xff, 0xff, 0xff, 0x1a, 0x0d, 0x40, 0xff, 0xff, 0xff, 0x22
+                                # LOE rbx r12 r13 r14 r15 zmm1
+
+/* Scalar math fucntion call
+ * to process special input
+ */
+
+L(SCALAR_MATH_CALL):
+        movl      %r12d, %r14d
+        movss     64(%rsp,%r14,4), %xmm0
+        call      log2f@PLT
+                                # LOE rbx r14 r15 r12d r13d xmm0
+
+        movss     %xmm0, 128(%rsp,%r14,4)
+
+/* Process special inputs in loop */
+        jmp       L(SPECIAL_VALUES_LOOP)
+                                # LOE rbx r15 r12d r13d
+END(_ZGVeN16v_log2f_skx)
+
+        .section .rodata, "a"
+        .align 64
+
+#ifdef __svml_slog2_data_internal_avx512_typedef
+typedef unsigned int VUINT32;
+typedef struct {
+        __declspec(align(64)) VUINT32 One[16][1];
+        __declspec(align(64)) VUINT32 coeff4[16][1];
+        __declspec(align(64)) VUINT32 coeff3[16][1];
+        __declspec(align(64)) VUINT32 coeff2[16][1];
+        __declspec(align(64)) VUINT32 coeff1[16][1];
+    } __svml_slog2_data_internal_avx512;
+#endif
+__svml_slog2_data_internal_avx512:
+        /*== One ==*/
+        .long 0x3f800000, 0x3f800000, 0x3f800000, 0x3f800000, 0x3f800000, 0x3f800000, 0x3f800000, 0x3f800000, 0x3f800000, 0x3f800000, 0x3f800000, 0x3f800000, 0x3f800000, 0x3f800000, 0x3f800000, 0x3f800000
+        // c4
+        .align 64
+        .long 0xbea77e4a, 0xbe8aae3d
+        .long 0xbe67fe32, 0xbe43d1b6
+        .long 0xbe26a589, 0xbe0ee09b
+        .long 0xbdf6a8a1, 0xbdd63b49
+        .long 0xbf584e51, 0xbf3e80a1
+        .long 0xbf2892f0, 0xbf15d377
+        .long 0xbf05b525, 0xbeef8e30
+        .long 0xbed75c8f, 0xbec24184
+        // c3
+        .align 64
+        .long 0x3ef5910c, 0x3ef045a1
+        .long 0x3ee7d87e, 0x3eddbb84
+        .long 0x3ed2d6df, 0x3ec7bbd2
+        .long 0x3ebcc42f, 0x3eb22616
+        .long 0x3e8f3399, 0x3eb1223e
+        .long 0x3ec9db4a, 0x3edb7a09
+        .long 0x3ee79a1a, 0x3eef77cb
+        .long 0x3ef407a4, 0x3ef607b4
+        // c2
+        .align 64
+        .long 0xbf38a934, 0xbf387de6
+        .long 0xbf37f6f0, 0xbf37048b
+        .long 0xbf35a88a, 0xbf33ed04
+        .long 0xbf31df56, 0xbf2f8d82
+        .long 0xbf416814, 0xbf3daf58
+        .long 0xbf3b5c08, 0xbf39fa2a
+        .long 0xbf393713, 0xbf38d7e1
+        .long 0xbf38b2cd, 0xbf38aa62
+        // c1
+        .align 64
+        .long 0x3fb8aa3b, 0x3fb8a9c0
+        .long 0x3fb8a6e8, 0x3fb89f4e
+        .long 0x3fb890cb, 0x3fb879b1
+        .long 0x3fb858d8, 0x3fb82d90
+        .long 0x3fb8655e, 0x3fb8883a
+        .long 0x3fb89aea, 0x3fb8a42f
+        .long 0x3fb8a848, 0x3fb8a9c9
+        .long 0x3fb8aa2f, 0x3fb8aa3b
+        .align 64
+        .type	__svml_slog2_data_internal_avx512,@object
+        .size	__svml_slog2_data_internal_avx512,.-__svml_slog2_data_internal_avx512