/* Function log2f vectorized with SSE4.
   Copyright (C) 2021-2022 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
 */
#define MinNorm                       	0
#define MaxNorm                       	16
#define iBrkValue                     	32
#define iOffExpoMask                  	48
#define One                           	64
#define sPoly                         	80

#include <sysdep.h>

        .text
	.section .text.sse4,"ax",@progbits
ENTRY(_ZGVbN4v_log2f_sse4)
        subq      $72, %rsp
        cfi_def_cfa_offset(80)
        movaps    %xmm0, %xmm1

/* reduction: compute r,n */
        movdqu    iBrkValue+__svml_slog2_data_internal(%rip), %xmm2
        movaps    %xmm0, %xmm4
        movdqu    iOffExpoMask+__svml_slog2_data_internal(%rip), %xmm10
        psubd     %xmm2, %xmm1
        pand      %xmm1, %xmm10
        movaps    %xmm0, %xmm3
        paddd     %xmm2, %xmm10
        psrad     $23, %xmm1
        movups    sPoly+__svml_slog2_data_internal(%rip), %xmm5
        movups    sPoly+32+__svml_slog2_data_internal(%rip), %xmm6
        movups    sPoly+64+__svml_slog2_data_internal(%rip), %xmm7
        movups    sPoly+96+__svml_slog2_data_internal(%rip), %xmm9
        cmpltps   MinNorm+__svml_slog2_data_internal(%rip), %xmm4
        cmpnleps  MaxNorm+__svml_slog2_data_internal(%rip), %xmm3
        cvtdq2ps  %xmm1, %xmm1
        subps     One+__svml_slog2_data_internal(%rip), %xmm10
        mulps     %xmm10, %xmm5
        movaps    %xmm10, %xmm8
        mulps     %xmm10, %xmm6
        mulps     %xmm10, %xmm8
        addps     sPoly+16+__svml_slog2_data_internal(%rip), %xmm5
        mulps     %xmm10, %xmm7
        addps     sPoly+48+__svml_slog2_data_internal(%rip), %xmm6
        mulps     %xmm10, %xmm9
        mulps     %xmm8, %xmm5
        addps     sPoly+80+__svml_slog2_data_internal(%rip), %xmm7
        addps     sPoly+112+__svml_slog2_data_internal(%rip), %xmm9
        addps     %xmm5, %xmm6
        mulps     %xmm8, %xmm6
        orps      %xmm3, %xmm4

/* combine and get argument value range mask */
        movmskps  %xmm4, %edx
        addps     %xmm6, %xmm7
        mulps     %xmm7, %xmm8
        addps     %xmm8, %xmm9
        mulps     %xmm10, %xmm9
        addps     sPoly+128+__svml_slog2_data_internal(%rip), %xmm9
        mulps     %xmm9, %xmm10
        addps     %xmm10, %xmm1
        testl     %edx, %edx

/* Go to special inputs processing branch */
        jne       L(SPECIAL_VALUES_BRANCH)
                                # LOE rbx rbp r12 r13 r14 r15 edx xmm0 xmm1

/* Restore registers
 * and exit the function
 */

L(EXIT):
        movaps    %xmm1, %xmm0
        addq      $72, %rsp
        cfi_def_cfa_offset(8)
        ret
        cfi_def_cfa_offset(80)

/* Branch to process
 * special inputs
 */

L(SPECIAL_VALUES_BRANCH):
        movups    %xmm0, 32(%rsp)
        movups    %xmm1, 48(%rsp)
                                # LOE rbx rbp r12 r13 r14 r15 edx

        xorl      %eax, %eax
        movq      %r12, 16(%rsp)
        cfi_offset(12, -64)
        movl      %eax, %r12d
        movq      %r13, 8(%rsp)
        cfi_offset(13, -72)
        movl      %edx, %r13d
        movq      %r14, (%rsp)
        cfi_offset(14, -80)
                                # LOE rbx rbp r15 r12d r13d

/* Range mask
 * bits check
 */

L(RANGEMASK_CHECK):
        btl       %r12d, %r13d

/* Call scalar math function */
        jc        L(SCALAR_MATH_CALL)
                                # LOE rbx rbp r15 r12d r13d

/* Special inputs
 * processing loop
 */

L(SPECIAL_VALUES_LOOP):
        incl      %r12d
        cmpl      $4, %r12d

/* Check bits in range mask */
        jl        L(RANGEMASK_CHECK)
                                # LOE rbx rbp r15 r12d r13d

        movq      16(%rsp), %r12
        cfi_restore(12)
        movq      8(%rsp), %r13
        cfi_restore(13)
        movq      (%rsp), %r14
        cfi_restore(14)
        movups    48(%rsp), %xmm1

/* Go to exit */
        jmp       L(EXIT)
        cfi_offset(12, -64)
        cfi_offset(13, -72)
        cfi_offset(14, -80)
                                # LOE rbx rbp r12 r13 r14 r15 xmm1

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

L(SCALAR_MATH_CALL):
        movl      %r12d, %r14d
        movss     32(%rsp,%r14,4), %xmm0
        call      log2f@PLT
                                # LOE rbx rbp r14 r15 r12d r13d xmm0

        movss     %xmm0, 48(%rsp,%r14,4)

/* Process special inputs in loop */
        jmp       L(SPECIAL_VALUES_LOOP)
                                # LOE rbx rbp r15 r12d r13d
END(_ZGVbN4v_log2f_sse4)

        .section .rodata, "a"
        .align 16

#ifdef __svml_slog2_data_internal_typedef
typedef unsigned int VUINT32;
typedef struct {
        __declspec(align(16)) VUINT32 MinNorm[4][1];
        __declspec(align(16)) VUINT32 MaxNorm[4][1];
        __declspec(align(16)) VUINT32 iBrkValue[4][1];
        __declspec(align(16)) VUINT32 iOffExpoMask[4][1];
        __declspec(align(16)) VUINT32 One[4][1];
        __declspec(align(16)) VUINT32 sPoly[9][4][1];
} __svml_slog2_data_internal;
#endif
__svml_slog2_data_internal:
        /*== MinNorm ==*/
        .long 0x00800000, 0x00800000, 0x00800000, 0x00800000
        /*== MaxNorm ==*/
        .align 16
        .long 0x7f7fffff, 0x7f7fffff, 0x7f7fffff, 0x7f7fffff
        /*== iBrkValue = SP 2/3 ==*/
        .align 16
        .long 0x3f2aaaab, 0x3f2aaaab, 0x3f2aaaab, 0x3f2aaaab
        /*== iOffExpoMask = SP significand mask ==*/
        .align 16
        .long 0x007fffff, 0x007fffff, 0x007fffff, 0x007fffff
        /*== sOne = SP 1.0 ==*/
        .align 16
        .long 0x3f800000, 0x3f800000, 0x3f800000, 0x3f800000
        /*== spoly[9] ==*/
        .align 16
        .long 0x3e554012, 0x3e554012, 0x3e554012, 0x3e554012 /* coeff9 */
        .long 0xbe638E14, 0xbe638E14, 0xbe638E14, 0xbe638E14 /* coeff8 */
        .long 0x3e4D660B, 0x3e4D660B, 0x3e4D660B, 0x3e4D660B /* coeff7 */
        .long 0xbe727824, 0xbe727824, 0xbe727824, 0xbe727824 /* coeff6 */
        .long 0x3e93DD07, 0x3e93DD07, 0x3e93DD07, 0x3e93DD07 /* coeff5 */
        .long 0xbeB8B969, 0xbeB8B969, 0xbeB8B969, 0xbeB8B969 /* coeff4 */
        .long 0x3eF637C0, 0x3eF637C0, 0x3eF637C0, 0x3eF637C0 /* coeff3 */
        .long 0xbf38AA2B, 0xbf38AA2B, 0xbf38AA2B, 0xbf38AA2B /* coeff2 */
        .long 0x3fB8AA3B, 0x3fB8AA3B, 0x3fB8AA3B, 0x3fB8AA3B /* coeff1 */
        .align 16
        .type	__svml_slog2_data_internal,@object
        .size	__svml_slog2_data_internal,.-__svml_slog2_data_internal
