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path: root/sysdeps/x86_64/fpu/multiarch/svml_s_expm1f16_core_avx512.S
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/* Function expm1f 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:
 *   After computing exp(x) in high-low parts, an accurate computation is performed to obtain exp(x)-1
 *   Typical exp() implementation, except that:
 *    - tables are small (32 elements), allowing for fast gathers
 *    - all arguments processed in the main path
 *        - final VSCALEF assists branch-free design (correct overflow/underflow and special case responses)
 *        - a VAND is used to ensure the reduced argument |R|<2, even for large inputs
 *        - RZ mode used to avoid oveflow to +/-Inf for x*log2(e); helps with special case handling
 *
 *
 */

/* Offsets for data table __svml_sexpm1_data_internal_avx512
 */
#define Exp_tbl_H                     	0
#define Exp_tbl_L                     	128
#define L2E                           	256
#define Shifter                       	320
#define Threshold                     	384
#define SgnMask                       	448
#define L2H                           	512
#define L2L                           	576
#define EMask                         	640
#define poly_coeff3                   	704
#define poly_coeff2                   	768
#define One                           	832

#include <sysdep.h>

        .text
	.section .text.exex512,"ax",@progbits
ENTRY(_ZGVeN16v_expm1f_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
        vmovups   L2E+__svml_sexpm1_data_internal_avx512(%rip), %zmm5
        vmovups   Shifter+__svml_sexpm1_data_internal_avx512(%rip), %zmm3
        vmovups   L2H+__svml_sexpm1_data_internal_avx512(%rip), %zmm8
        vmovups   L2L+__svml_sexpm1_data_internal_avx512(%rip), %zmm4
        vmovups   __svml_sexpm1_data_internal_avx512(%rip), %zmm6

/* polynomial */
        vmovups   poly_coeff3+__svml_sexpm1_data_internal_avx512(%rip), %zmm9
        vmovups   poly_coeff2+__svml_sexpm1_data_internal_avx512(%rip), %zmm12
        vmovups   Exp_tbl_L+__svml_sexpm1_data_internal_avx512(%rip), %zmm11
        vmovups   Threshold+__svml_sexpm1_data_internal_avx512(%rip), %zmm2

/* Th - 1 */
        vmovups   One+__svml_sexpm1_data_internal_avx512(%rip), %zmm14
        vmovaps   %zmm0, %zmm1

/* 2^(52-5)*1.5 + x * log2(e) */
        vfmadd213ps {rn-sae}, %zmm3, %zmm1, %zmm5
        vcmpps    $29, {sae}, %zmm2, %zmm1, %k0

/* Z0 ~ x*log2(e), rounded to 5 fractional bits */
        vsubps    {rn-sae}, %zmm3, %zmm5, %zmm7
        vpermt2ps Exp_tbl_H+64+__svml_sexpm1_data_internal_avx512(%rip), %zmm5, %zmm6
        vpermt2ps Exp_tbl_L+64+__svml_sexpm1_data_internal_avx512(%rip), %zmm5, %zmm11
        vandps    SgnMask+__svml_sexpm1_data_internal_avx512(%rip), %zmm1, %zmm0

/* R = x - Z0*log(2) */
        vfnmadd213ps {rn-sae}, %zmm1, %zmm7, %zmm8

/* scale Th */
        vscalefps {rn-sae}, %zmm7, %zmm6, %zmm2
        vfnmadd231ps {rn-sae}, %zmm7, %zmm4, %zmm8
        kmovw     %k0, %edx

/* ensure |R|<2 even for special cases */
        vandps    EMask+__svml_sexpm1_data_internal_avx512(%rip), %zmm8, %zmm13
        vsubps    {rn-sae}, %zmm14, %zmm2, %zmm8
        vmulps    {rn-sae}, %zmm13, %zmm13, %zmm10
        vfmadd231ps {rn-sae}, %zmm13, %zmm9, %zmm12

/* Tlr + R+ R2*Poly */
        vfmadd213ps {rn-sae}, %zmm11, %zmm10, %zmm12
        vaddps    {rn-sae}, %zmm13, %zmm12, %zmm15

/* (Th-1)+Th*(Tlr + R+ R*Poly) */
        vfmadd213ps {rn-sae}, %zmm8, %zmm15, %zmm2
        vorps     %zmm0, %zmm2, %zmm0
        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):
        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   %zmm1, 64(%rsp)
        vmovups   %zmm0, 128(%rsp)
                                # LOE rbx r12 r13 r14 r15 edx zmm0

        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), %zmm0

/* 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 zmm0

/* Scalar math fucntion call
 * to process special input
 */

L(SCALAR_MATH_CALL):
        movl      %r12d, %r14d
        movss     64(%rsp,%r14,4), %xmm0
        call      expm1f@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_expm1f_skx)

        .section .rodata, "a"
        .align 64

#ifdef __svml_sexpm1_data_internal_avx512_typedef
typedef unsigned int VUINT32;
typedef struct {
        __declspec(align(64)) VUINT32 Exp_tbl_H[32][1];
        __declspec(align(64)) VUINT32 Exp_tbl_L[32][1];
        __declspec(align(64)) VUINT32 L2E[16][1];
        __declspec(align(64)) VUINT32 Shifter[16][1];
        __declspec(align(64)) VUINT32 Threshold[16][1];
        __declspec(align(64)) VUINT32 SgnMask[16][1];
        __declspec(align(64)) VUINT32 L2H[16][1];
        __declspec(align(64)) VUINT32 L2L[16][1];
        __declspec(align(64)) VUINT32 EMask[16][1];
        __declspec(align(64)) VUINT32 poly_coeff3[16][1];
        __declspec(align(64)) VUINT32 poly_coeff2[16][1];
        __declspec(align(64)) VUINT32 One[16][1];
    } __svml_sexpm1_data_internal_avx512;
#endif
__svml_sexpm1_data_internal_avx512:
        /*== Exp_tbl_H ==*/
        .long 0x3f800000, 0x3f82cd87, 0x3f85aac3, 0x3f88980f
        .long 0x3f8b95c2, 0x3f8ea43a, 0x3f91c3d3, 0x3f94f4f0
        .long 0x3f9837f0, 0x3f9b8d3a, 0x3f9ef532, 0x3fa27043
        .long 0x3fa5fed7, 0x3fa9a15b, 0x3fad583f, 0x3fb123f6
        .long 0x3fb504f3, 0x3fb8fbaf, 0x3fbd08a4, 0x3fc12c4d
        .long 0x3fc5672a, 0x3fc9b9be, 0x3fce248c, 0x3fd2a81e
        .long 0x3fd744fd, 0x3fdbfbb8, 0x3fe0ccdf, 0x3fe5b907
        .long 0x3feac0c7, 0x3fefe4ba, 0x3ff5257d, 0x3ffa83b3
        /*== Exp_tbl_L ==*/
        .align 64
        .long 0x00000000, 0xb34a3a0a, 0x3346cb6a, 0xb36ed17e
        .long 0xb24e0611, 0xb3517dd9, 0x334b2482, 0xb31586de
        .long 0x33092801, 0xb2e6f467, 0x331b85f2, 0x3099b6f1
        .long 0xb3051aa8, 0xb2e2a0da, 0xb2006c56, 0xb3365942
        .long 0x329302ae, 0x32c595dc, 0xb302e5a2, 0xb28e10a1
        .long 0x31b3d0e5, 0xb31a472b, 0x31d1daf2, 0xb305bf64
        .long 0xb27ce182, 0xb2f26443, 0xb1b4b0da, 0xb1da8a8f
        .long 0xb1d290be, 0xb2d5b899, 0x31b0a147, 0xb2156afc
        /*== log2(e) ==*/
        .align 64
        .long 0x3fB8AA3B, 0x3fB8AA3B, 0x3fB8AA3B, 0x3fB8AA3B, 0x3fB8AA3B, 0x3fB8AA3B, 0x3fB8AA3B, 0x3fB8AA3B, 0x3fB8AA3B, 0x3fB8AA3B, 0x3fB8AA3B, 0x3fB8AA3B, 0x3fB8AA3B, 0x3fB8AA3B, 0x3fB8AA3B, 0x3fB8AA3B
        /*== Shifter=2^(23-5)*1.5 ==*/
        .align 64
        .long 0x48c00000, 0x48c00000, 0x48c00000, 0x48c00000, 0x48c00000, 0x48c00000, 0x48c00000, 0x48c00000, 0x48c00000, 0x48c00000, 0x48c00000, 0x48c00000, 0x48c00000, 0x48c00000, 0x48c00000, 0x48c00000
        /*== Threshold ==*/
        .align 64
        .long 0x42AD496B, 0x42AD496B, 0x42AD496B, 0x42AD496B, 0x42AD496B, 0x42AD496B, 0x42AD496B, 0x42AD496B, 0x42AD496B, 0x42AD496B, 0x42AD496B, 0x42AD496B, 0x42AD496B, 0x42AD496B, 0x42AD496B, 0x42AD496B
        /*== Sgn ==*/
        .align 64
        .long 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000
        /*== L2H = log(2)_high ==*/
        .align 64
        .long 0x3f317218, 0x3f317218, 0x3f317218, 0x3f317218, 0x3f317218, 0x3f317218, 0x3f317218, 0x3f317218, 0x3f317218, 0x3f317218, 0x3f317218, 0x3f317218, 0x3f317218, 0x3f317218, 0x3f317218, 0x3f317218
        /*== L2L = log(2)_low ==*/
        .align 64
        .long 0xb102e308, 0xb102e308, 0xb102e308, 0xb102e308, 0xb102e308, 0xb102e308, 0xb102e308, 0xb102e308, 0xb102e308, 0xb102e308, 0xb102e308, 0xb102e308, 0xb102e308, 0xb102e308, 0xb102e308, 0xb102e308
        /*== EMask ==*/
        .align 64
        .long 0xbfffffff, 0xbfffffff, 0xbfffffff, 0xbfffffff, 0xbfffffff, 0xbfffffff, 0xbfffffff, 0xbfffffff, 0xbfffffff, 0xbfffffff, 0xbfffffff, 0xbfffffff, 0xbfffffff, 0xbfffffff, 0xbfffffff, 0xbfffffff
        /*== poly_coeff3 ==*/
        .align 64
        .long 0x3e2AABF3, 0x3e2AABF3, 0x3e2AABF3, 0x3e2AABF3, 0x3e2AABF3, 0x3e2AABF3, 0x3e2AABF3, 0x3e2AABF3, 0x3e2AABF3, 0x3e2AABF3, 0x3e2AABF3, 0x3e2AABF3, 0x3e2AABF3, 0x3e2AABF3, 0x3e2AABF3, 0x3e2AABF3
        /*== poly_coeff2 ==*/
        .align 64
        .long 0x3f0000F6, 0x3f0000F6, 0x3f0000F6, 0x3f0000F6, 0x3f0000F6, 0x3f0000F6, 0x3f0000F6, 0x3f0000F6, 0x3f0000F6, 0x3f0000F6, 0x3f0000F6, 0x3f0000F6, 0x3f0000F6, 0x3f0000F6, 0x3f0000F6, 0x3f0000F6
        /*== One ==*/
        .align 64
        .long 0x3f800000, 0x3f800000, 0x3f800000, 0x3f800000, 0x3f800000, 0x3f800000, 0x3f800000, 0x3f800000, 0x3f800000, 0x3f800000, 0x3f800000, 0x3f800000, 0x3f800000, 0x3f800000, 0x3f800000, 0x3f800000
        .align 64
        .type	__svml_sexpm1_data_internal_avx512,@object
        .size	__svml_sexpm1_data_internal_avx512,.-__svml_sexpm1_data_internal_avx512