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authorWerner Koch <wk@gnupg.org>1998-02-12 19:52:41 +0000
committerWerner Koch <wk@gnupg.org>1998-02-12 19:52:41 +0000
commit5875b2a7be7f563e675738fa7d776fdac0b1dcfe (patch)
tree812d6238ff02c9124a4596f096404fb47633b8fd /mpi/hppa1.1/mpih-mul1.S
parentcef50a1d925b0eb7f5aef31eacdfe943f9f4c835 (diff)
downloadlibgcrypt-5875b2a7be7f563e675738fa7d776fdac0b1dcfe.tar.gz
added assembler stuff for hppa
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+/* hppa1.1 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.
+ * Copyright (c) 1998 by Werner Koch (dd9jn)
+ *
+ * This file is part of G10.
+ *
+ * G10 is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * G10 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
+ *
+ * Note: This code is heavily based on the GNU MP Library.
+ * Actually it's the same code with only minor changes in the
+ * way the data is stored; this is to support the abstraction
+ * of an optional secure memory allocation which may be used
+ * to avoid revealing of sensitive data due to paging etc.
+ * The GNU MP Library itself is published under the LGPL;
+ * however I decided to publish this code under the plain GPL.
+ */
+
+
+/*******************
+ * mpi_limb_t
+ * mpihelp_mul_1( mpi_ptr_t res_ptr, (r26)
+ * mpi_ptr_t s1_ptr, (r25)
+ * mpi_size_t s1_size, (r24)
+ * mpi_limb_t 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 mpihelp_mul_1
+mpihelp_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
+
+