github.com/aergoio/aergo@v1.3.1/libtool/src/gmp-6.1.2/mpn/x86_64/k10/popcount.asm (about)

     1  dnl  AMD64 mpn_popcount -- population count.
     2  
     3  dnl  Copyright 2008, 2010-2012 Free Software Foundation, Inc.
     4  
     5  dnl  This file is part of the GNU MP Library.
     6  dnl
     7  dnl  The GNU MP Library is free software; you can redistribute it and/or modify
     8  dnl  it under the terms of either:
     9  dnl
    10  dnl    * the GNU Lesser General Public License as published by the Free
    11  dnl      Software Foundation; either version 3 of the License, or (at your
    12  dnl      option) any later version.
    13  dnl
    14  dnl  or
    15  dnl
    16  dnl    * the GNU General Public License as published by the Free Software
    17  dnl      Foundation; either version 2 of the License, or (at your option) any
    18  dnl      later version.
    19  dnl
    20  dnl  or both in parallel, as here.
    21  dnl
    22  dnl  The GNU MP Library is distributed in the hope that it will be useful, but
    23  dnl  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
    24  dnl  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
    25  dnl  for more details.
    26  dnl
    27  dnl  You should have received copies of the GNU General Public License and the
    28  dnl  GNU Lesser General Public License along with the GNU MP Library.  If not,
    29  dnl  see https://www.gnu.org/licenses/.
    30  
    31  include(`../config.m4')
    32  
    33  C		    cycles/limb
    34  C AMD K8,K9		 n/a
    35  C AMD K10		 1.125
    36  C Intel P4		 n/a
    37  C Intel core2		 n/a
    38  C Intel corei		 1.25
    39  C Intel atom		 n/a
    40  C VIA nano		 n/a
    41  
    42  C * The zero-offset of popcount is misassembled to the offset-less form, which
    43  C   is one byte shorter and therefore will mess up the switching code.
    44  C * The outdated gas used in FreeBSD and NetBSD cannot handle the POPCNT insn,
    45  C   which is the main reason for our usage of '.byte'.
    46  
    47  C TODO
    48  C  * Improve switching code, the current code sucks.
    49  
    50  define(`up',		`%rdi')
    51  define(`n',		`%rsi')
    52  
    53  ABI_SUPPORT(DOS64)
    54  ABI_SUPPORT(STD64)
    55  
    56  ASM_START()
    57  	TEXT
    58  	ALIGN(32)
    59  PROLOGUE(mpn_popcount)
    60  	FUNC_ENTRY(2)
    61  
    62  ifelse(1,1,`
    63  	lea	(up,n,8), up
    64  
    65  C	mov	R32(n), R32(%rcx)
    66  C	neg	R32(%rcx)
    67  	imul	$-1, R32(n), R32(%rcx)
    68  	and	$8-1, R32(%rcx)
    69  
    70  	neg	n
    71  
    72  	mov	R32(%rcx), R32(%rax)
    73  	neg	%rax
    74  	lea	(up,%rax,8),up
    75  
    76  	xor	R32(%rax), R32(%rax)
    77  
    78  	lea	(%rcx,%rcx,4), %rcx
    79  
    80  	lea	L(top)(%rip), %rdx
    81  	lea	(%rdx,%rcx,2), %rdx
    82  	jmp	*%rdx
    83  ',`
    84  	lea	(up,n,8), up
    85  
    86  	mov	R32(n), R32(%rcx)
    87  	neg	R32(%rcx)
    88  	and	$8-1, R32(%rcx)
    89  
    90  	neg	n
    91  
    92  	mov	R32(%rcx), R32(%rax)
    93  	shl	$3, R32(%rax)
    94  	sub	%rax, up
    95  
    96  	xor	R32(%rax), R32(%rax)
    97  
    98  C	add	R32(%rcx), R32(%rcx)	C 2x
    99  C	lea	(%rcx,%rcx,4), %rcx	C 10x
   100  	imul	$10, R32(%rcx)
   101  
   102  	lea	L(top)(%rip), %rdx
   103  	add	%rcx, %rdx
   104  	jmp	*%rdx
   105  ')
   106  
   107  	ALIGN(32)
   108  L(top):
   109  C 0 = n mod 8
   110  	.byte	0xf3,0x4c,0x0f,0xb8,0x44,0xf7,0x00	C popcnt 0(up,n,8), %r8
   111  	add	%r8, %rax
   112  C 7 = n mod 8
   113  	.byte	0xf3,0x4c,0x0f,0xb8,0x4c,0xf7,0x08	C popcnt 8(up,n,8), %r9
   114  	add	%r9, %rax
   115  C 6 = n mod 8
   116  	.byte	0xf3,0x4c,0x0f,0xb8,0x44,0xf7,0x10	C popcnt 16(up,n,8), %r8
   117  	add	%r8, %rax
   118  C 5 = n mod 8
   119  	.byte	0xf3,0x4c,0x0f,0xb8,0x4c,0xf7,0x18	C popcnt 24(up,n,8), %r9
   120  	add	%r9, %rax
   121  C 4 = n mod 8
   122  	.byte	0xf3,0x4c,0x0f,0xb8,0x44,0xf7,0x20	C popcnt 32(up,n,8), %r8
   123  	add	%r8, %rax
   124  C 3 = n mod 8
   125  	.byte	0xf3,0x4c,0x0f,0xb8,0x4c,0xf7,0x28	C popcnt 40(up,n,8), %r9
   126  	add	%r9, %rax
   127  C 2 = n mod 8
   128  	.byte	0xf3,0x4c,0x0f,0xb8,0x44,0xf7,0x30	C popcnt 48(up,n,8), %r8
   129  	add	%r8, %rax
   130  C 1 = n mod 8
   131  	.byte	0xf3,0x4c,0x0f,0xb8,0x4c,0xf7,0x38	C popcnt 56(up,n,8), %r9
   132  	add	%r9, %rax
   133  
   134  	add	$8, n
   135  	js	L(top)
   136  	FUNC_EXIT()
   137  	ret
   138  EPILOGUE()