about summary refs log tree commit diff
path: root/sysdeps/hppa/hppa1.1/mul_1.s
diff options
context:
space:
mode:
Diffstat (limited to 'sysdeps/hppa/hppa1.1/mul_1.s')
-rw-r--r--sysdeps/hppa/hppa1.1/mul_1.s97
1 files changed, 97 insertions, 0 deletions
diff --git a/sysdeps/hppa/hppa1.1/mul_1.s b/sysdeps/hppa/hppa1.1/mul_1.s
new file mode 100644
index 0000000000..ebf0778b90
--- /dev/null
+++ b/sysdeps/hppa/hppa1.1/mul_1.s
@@ -0,0 +1,97 @@
+; HP-PA-1.1 __mpn_mul_1 -- Multiply a limb vector with a limb and store
+; the result in a second limb vector.
+
+; Copyright (C) 1992, 1993, 1994 Free Software Foundation, Inc.
+
+; This file is part of the GNU MP Library.
+
+; The GNU MP Library is free software; you can redistribute it and/or modify
+; it under the terms of the GNU Library General Public License as published by
+; the Free Software Foundation; either version 2 of the License, or (at your
+; option) any later version.
+
+; The GNU MP 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 Library General Public
+; License for more details.
+
+; You should have received a copy of the GNU Library General Public License
+; along with the GNU MP Library; see the file COPYING.LIB.  If not, write to
+; the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+
+; INPUT PARAMETERS
+; res_ptr	r26
+; s1_ptr	r25
+; size		r24
+; s2_limb	r23
+
+; This runs at 9 cycles/limb on a PA7000.  With the used instructions, it can
+; not become faster due to data cache contention after a store.  On the
+; PA7100 it runs at 7 cycles/limb, and that can not be improved either, since
+; only the xmpyu does not need the integer pipeline, so the only dual-issue
+; we will get are addc+xmpyu.  Unrolling would not help either CPU.
+
+; We could use fldds to read two limbs at a time from the S1 array, and that
+; could bring down the times to 8.5 and 6.5 cycles/limb for the PA7000 and
+; PA7100, respectively.  We don't do that since it does not seem worth the
+; (alignment) troubles...
+
+; At least the PA7100 is rumored to be able to deal with cache-misses
+; without stalling instruction issue.  If this is true, and the cache is
+; actually also lockup-free, we should use a deeper software pipeline, and
+; load from S1 very early!  (The loads and stores to -12(sp) will surely be
+; in the cache.)
+
+	.code
+	.export		__mpn_mul_1
+__mpn_mul_1
+	.proc
+	.callinfo	frame=64,no_calls
+	.entry
+
+	ldo		64(%r30),%r30
+	fldws,ma	4(%r25),%fr5
+	stw		%r23,-16(%r30)		; move s2_limb ...
+	addib,=		-1,%r24,L$just_one_limb
+	 fldws		-16(%r30),%fr4		; ... into fr4
+	add		%r0,%r0,%r0		; clear carry
+	xmpyu		%fr4,%fr5,%fr6
+	fldws,ma	4(%r25),%fr7
+	fstds	 	%fr6,-16(%r30)
+	xmpyu		%fr4,%fr7,%fr8
+	ldw		-12(%r30),%r19		; least significant limb in product
+	ldw		-16(%r30),%r28
+
+	fstds		%fr8,-16(%r30)
+	addib,=		-1,%r24,L$end
+	 ldw		-12(%r30),%r1
+
+; Main loop
+L$loop	fldws,ma	4(%r25),%fr5
+	stws,ma		%r19,4(%r26)
+	addc		%r28,%r1,%r19
+	xmpyu		%fr4,%fr5,%fr6
+	ldw		-16(%r30),%r28
+	fstds		%fr6,-16(%r30)
+	addib,<>	-1,%r24,L$loop
+	 ldw		-12(%r30),%r1
+
+L$end	stws,ma		%r19,4(%r26)
+	addc		%r28,%r1,%r19
+	ldw		-16(%r30),%r28
+	stws,ma		%r19,4(%r26)
+	addc		%r0,%r28,%r28
+	bv		0(%r2)
+	 ldo		-64(%r30),%r30
+
+L$just_one_limb
+	xmpyu		%fr4,%fr5,%fr6
+	fstds		%fr6,-16(%r30)
+	ldw		-16(%r30),%r28
+	ldo		-64(%r30),%r30
+	bv		0(%r2)
+	 fstws		%fr6R,0(%r26)
+
+	.exit
+	.procend