1;! HP-PA-1.1 __mpn_mul_1 -- Multiply a limb vector with a limb and store
2;! the result in a second limb vector.
3
4;! Copyright (C) 1992-2021 Free Software Foundation, Inc.
5
6;! This file is part of the GNU MP Library.
7
8;! The GNU MP Library is free software; you can redistribute it and/or modify
9;! it under the terms of the GNU Lesser General Public License as published by
10;! the Free Software Foundation; either version 2.1 of the License, or (at your
11;! option) any later version.
12
13;! The GNU MP Library is distributed in the hope that it will be useful, but
14;! WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
15;! or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
16;! License for more details.
17
18;! You should have received a copy of the GNU Lesser General Public License
19;! along with the GNU MP Library.  If not, see
20;! <https://www.gnu.org/licenses/>.
21
22
23;! INPUT PARAMETERS
24;! res_ptr	r26
25;! s1_ptr	r25
26;! size		r24
27;! s2_limb	r23
28
29;! This runs at 9 cycles/limb on a PA7000.  With the used instructions, it can
30;! not become faster due to data cache contention after a store.  On the
31;! PA7100 it runs at 7 cycles/limb, and that can not be improved either, since
32;! only the xmpyu does not need the integer pipeline, so the only dual-issue
33;! we will get are addc+xmpyu.  Unrolling would not help either CPU.
34
35;! We could use fldds to read two limbs at a time from the S1 array, and that
36;! could bring down the times to 8.5 and 6.5 cycles/limb for the PA7000 and
37;! PA7100, respectively.  We don't do that since it does not seem worth the
38;! (alignment) troubles...
39
40;! At least the PA7100 is rumored to be able to deal with cache-misses
41;! without stalling instruction issue.  If this is true, and the cache is
42;! actually also lockup-free, we should use a deeper software pipeline, and
43;! load from S1 very early;  (The loads and stores to -12(sp) will surely be
44;! in the cache.)
45
46	.text
47	.export		__mpn_mul_1
48__mpn_mul_1:
49	.proc
50	.callinfo	frame=64,no_calls
51	.entry
52
53	ldo		64(%r30),%r30
54	fldws,ma	4(%r25),%fr5
55	stw		%r23,-16(%r30)		;! move s2_limb ...
56	addib,=		-1,%r24,L$just_one_limb
57	 fldws		-16(%r30),%fr4		;! ... into fr4
58	add		%r0,%r0,%r0		;! clear carry
59	xmpyu		%fr4,%fr5,%fr6
60	fldws,ma	4(%r25),%fr7
61	fstds	 	%fr6,-16(%r30)
62	xmpyu		%fr4,%fr7,%fr8
63	ldw		-12(%r30),%r20		;! least significant limb in product
64	ldw		-16(%r30),%r28
65
66	fstds		%fr8,-16(%r30)
67	addib,=		-1,%r24,L$end
68	 ldw		-12(%r30),%r1
69
70;! Main loop
71L$loop:
72	fldws,ma	4(%r25),%fr5
73	stws,ma		%r20,4(%r26)
74	addc		%r28,%r1,%r20
75	xmpyu		%fr4,%fr5,%fr6
76	ldw		-16(%r30),%r28
77	fstds		%fr6,-16(%r30)
78	addib,<>	-1,%r24,L$loop
79	 ldw		-12(%r30),%r1
80
81L$end:
82	stws,ma		%r20,4(%r26)
83	addc		%r28,%r1,%r20
84	ldw		-16(%r30),%r28
85	stws,ma		%r20,4(%r26)
86	addc		%r0,%r28,%r28
87	bv		0(%r2)
88	 ldo		-64(%r30),%r30
89
90L$just_one_limb:
91	xmpyu		%fr4,%fr5,%fr6
92	fstds		%fr6,-16(%r30)
93	ldw		-16(%r30),%r28
94	ldo		-64(%r30),%r30
95	bv		0(%r2)
96	 fstws		%fr6R,0(%r26)
97
98	.exit
99	.procend
100