github.com/aergoio/aergo@v1.3.1/libtool/src/gmp-6.1.2/mpn/pa32/hppa1_1/submul_1.asm (about)

     1  dnl  HP-PA 1.1 mpn_submul_1 -- Multiply a limb vector with a limb and subtract
     2  dnl  the result from a second limb vector.
     3  
     4  dnl  Copyright 1992-1994, 2000-2002 Free Software Foundation, Inc.
     5  
     6  dnl  This file is part of the GNU MP Library.
     7  dnl
     8  dnl  The GNU MP Library is free software; you can redistribute it and/or modify
     9  dnl  it under the terms of either:
    10  dnl
    11  dnl    * the GNU Lesser General Public License as published by the Free
    12  dnl      Software Foundation; either version 3 of the License, or (at your
    13  dnl      option) any later version.
    14  dnl
    15  dnl  or
    16  dnl
    17  dnl    * the GNU General Public License as published by the Free Software
    18  dnl      Foundation; either version 2 of the License, or (at your option) any
    19  dnl      later version.
    20  dnl
    21  dnl  or both in parallel, as here.
    22  dnl
    23  dnl  The GNU MP Library is distributed in the hope that it will be useful, but
    24  dnl  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
    25  dnl  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
    26  dnl  for more details.
    27  dnl
    28  dnl  You should have received copies of the GNU General Public License and the
    29  dnl  GNU Lesser General Public License along with the GNU MP Library.  If not,
    30  dnl  see https://www.gnu.org/licenses/.
    31  
    32  include(`../config.m4')
    33  
    34  C INPUT PARAMETERS
    35  C res_ptr	r26
    36  C s1_ptr	r25
    37  C size		r24
    38  C s2_limb	r23
    39  
    40  C This runs at 12 cycles/limb on a PA7000.  With the used instructions, it can
    41  C not become faster due to data cache contention after a store.  On the PA7100
    42  C it runs at 11 cycles/limb.
    43  
    44  C There are some ideas described in mul_1.asm that applies to this code too.
    45  
    46  C It seems possible to make this run as fast as mpn_addmul_1, if we use
    47  C	sub,>>=	%r29,%r19,%r22
    48  C	addi	1,%r28,%r28
    49  C but that requires reworking the hairy software pipeline...
    50  
    51  ASM_START()
    52  PROLOGUE(mpn_submul_1)
    53  C	.callinfo	frame=64,no_calls
    54  
    55  	ldo		64(%r30),%r30
    56  	fldws,ma	4(%r25),%fr5
    57  	stw		%r23,-16(%r30)		C move s2_limb ...
    58  	addib,=		-1,%r24,L(just_one_limb)
    59  	 fldws		-16(%r30),%fr4		C ... into fr4
    60  	add		%r0,%r0,%r0		C clear carry
    61  	xmpyu		%fr4,%fr5,%fr6
    62  	fldws,ma	4(%r25),%fr7
    63  	fstds		%fr6,-16(%r30)
    64  	xmpyu		%fr4,%fr7,%fr8
    65  	ldw		-12(%r30),%r19		C least significant limb in product
    66  	ldw		-16(%r30),%r28
    67  
    68  	fstds		%fr8,-16(%r30)
    69  	addib,=		-1,%r24,L(end)
    70  	 ldw		-12(%r30),%r1
    71  
    72  C Main loop
    73  LDEF(loop)
    74  	ldws		0(%r26),%r29
    75  	fldws,ma	4(%r25),%fr5
    76  	sub		%r29,%r19,%r22
    77  	add		%r22,%r19,%r0
    78  	stws,ma		%r22,4(%r26)
    79  	addc		%r28,%r1,%r19
    80  	xmpyu		%fr4,%fr5,%fr6
    81  	ldw		-16(%r30),%r28
    82  	fstds		%fr6,-16(%r30)
    83  	addc		%r0,%r28,%r28
    84  	addib,<>	-1,%r24,L(loop)
    85  	 ldw		-12(%r30),%r1
    86  
    87  LDEF(end)
    88  	ldw		0(%r26),%r29
    89  	sub		%r29,%r19,%r22
    90  	add		%r22,%r19,%r0
    91  	stws,ma		%r22,4(%r26)
    92  	addc		%r28,%r1,%r19
    93  	ldw		-16(%r30),%r28
    94  	ldws		0(%r26),%r29
    95  	addc		%r0,%r28,%r28
    96  	sub		%r29,%r19,%r22
    97  	add		%r22,%r19,%r0
    98  	stws,ma		%r22,4(%r26)
    99  	addc		%r0,%r28,%r28
   100  	bv		0(%r2)
   101  	 ldo		-64(%r30),%r30
   102  
   103  LDEF(just_one_limb)
   104  	xmpyu		%fr4,%fr5,%fr6
   105  	ldw		0(%r26),%r29
   106  	fstds		%fr6,-16(%r30)
   107  	ldw		-12(%r30),%r1
   108  	ldw		-16(%r30),%r28
   109  	sub		%r29,%r1,%r22
   110  	add		%r22,%r1,%r0
   111  	stw		%r22,0(%r26)
   112  	addc		%r0,%r28,%r28
   113  	bv		0(%r2)
   114  	 ldo		-64(%r30),%r30
   115  EPILOGUE()