github.com/aergoio/aergo@v1.3.1/libtool/src/gmp-6.1.2/mpn/x86/k7/mmx/copyd.asm (about)

     1  dnl  AMD K7 mpn_copyd -- copy limb vector, decrementing.
     2  
     3  dnl  Copyright 1999, 2000, 2002 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  
    34  C    alignment dst/src, A=0mod8 N=4mod8
    35  C       A/A   A/N   N/A   N/N
    36  C K7    0.75  1.0   1.0   0.75
    37  
    38  
    39  C void mpn_copyd (mp_ptr dst, mp_srcptr src, mp_size_t size);
    40  C
    41  C The various comments in mpn/x86/k7/copyi.asm apply here too.
    42  
    43  defframe(PARAM_SIZE,12)
    44  defframe(PARAM_SRC, 8)
    45  defframe(PARAM_DST, 4)
    46  deflit(`FRAME',0)
    47  
    48  dnl  parameter space reused
    49  define(SAVE_EBX,`PARAM_SIZE')
    50  define(SAVE_ESI,`PARAM_SRC')
    51  
    52  dnl  minimum 5 since the unrolled code can't handle less than 5
    53  deflit(UNROLL_THRESHOLD, 5)
    54  
    55  	TEXT
    56  	ALIGN(32)
    57  PROLOGUE(mpn_copyd)
    58  
    59  	movl	PARAM_SIZE, %ecx
    60  	movl	%ebx, SAVE_EBX
    61  
    62  	movl	PARAM_SRC, %eax
    63  	movl	PARAM_DST, %edx
    64  
    65  	cmpl	$UNROLL_THRESHOLD, %ecx
    66  	jae	L(unroll)
    67  
    68  	orl	%ecx, %ecx
    69  	jz	L(simple_done)
    70  
    71  L(simple):
    72  	C eax	src
    73  	C ebx	scratch
    74  	C ecx	counter
    75  	C edx	dst
    76  	C
    77  	C this loop is 2 cycles/limb
    78  
    79  	movl	-4(%eax,%ecx,4), %ebx
    80  	movl	%ebx, -4(%edx,%ecx,4)
    81  	decl	%ecx
    82  	jnz	L(simple)
    83  
    84  L(simple_done):
    85  	movl	SAVE_EBX, %ebx
    86  	ret
    87  
    88  
    89  L(unroll):
    90  	movl	%esi, SAVE_ESI
    91  	leal	(%eax,%ecx,4), %ebx
    92  	leal	(%edx,%ecx,4), %esi
    93  
    94  	andl	%esi, %ebx
    95  	movl	SAVE_ESI, %esi
    96  	subl	$4, %ecx		C size-4
    97  
    98  	testl	$4, %ebx   C testl to pad code closer to 16 bytes for L(top)
    99  	jz	L(aligned)
   100  
   101  	C both src and dst unaligned, process one limb to align them
   102  	movl	12(%eax,%ecx,4), %ebx
   103  	movl	%ebx, 12(%edx,%ecx,4)
   104  	decl	%ecx
   105  L(aligned):
   106  
   107  
   108  	ALIGN(16)
   109  L(top):
   110  	C eax	src
   111  	C ebx
   112  	C ecx	counter, limbs
   113  	C edx	dst
   114  
   115  	movq	8(%eax,%ecx,4), %mm0
   116  	movq	(%eax,%ecx,4), %mm1
   117  	subl	$4, %ecx
   118  	movq	%mm0, 16+8(%edx,%ecx,4)
   119  	movq	%mm1, 16(%edx,%ecx,4)
   120  	jns	L(top)
   121  
   122  
   123  	C now %ecx is -4 to -1 representing respectively 0 to 3 limbs remaining
   124  
   125  	testb	$2, %cl
   126  	jz	L(finish_not_two)
   127  
   128  	movq	8(%eax,%ecx,4), %mm0
   129  	movq	%mm0, 8(%edx,%ecx,4)
   130  L(finish_not_two):
   131  
   132  	testb	$1, %cl
   133  	jz	L(done)
   134  
   135  	movl	(%eax), %ebx
   136  	movl	%ebx, (%edx)
   137  
   138  L(done):
   139  	movl	SAVE_EBX, %ebx
   140  	emms
   141  	ret
   142  
   143  
   144  EPILOGUE()