aboutsummaryrefslogtreecommitdiff
path: root/sysdeps/alpha/mul_1.s
diff options
context:
space:
mode:
authorRoland McGrath <roland@gnu.org>1995-10-16 01:18:40 +0000
committerRoland McGrath <roland@gnu.org>1995-10-16 01:18:40 +0000
commit7def3d92a4edd807d2df2f016e5c1d6b8e748358 (patch)
treecb797a8d8afbc5bbdcfef1defab169a92eaa9b8c /sysdeps/alpha/mul_1.s
parent3a29975f0ad24500841791878ca9906315f7592e (diff)
downloadglibc-7def3d92a4edd807d2df2f016e5c1d6b8e748358.tar
glibc-7def3d92a4edd807d2df2f016e5c1d6b8e748358.tar.gz
glibc-7def3d92a4edd807d2df2f016e5c1d6b8e748358.tar.bz2
glibc-7def3d92a4edd807d2df2f016e5c1d6b8e748358.zip
Updated from ../=mpn/gmp-1.906.7
Diffstat (limited to 'sysdeps/alpha/mul_1.s')
-rw-r--r--sysdeps/alpha/mul_1.s84
1 files changed, 84 insertions, 0 deletions
diff --git a/sysdeps/alpha/mul_1.s b/sysdeps/alpha/mul_1.s
new file mode 100644
index 0000000000..3ef194d7e6
--- /dev/null
+++ b/sysdeps/alpha/mul_1.s
@@ -0,0 +1,84 @@
+ # Alpha 21064 __mpn_mul_1 -- Multiply a limb vector with a limb and store
+ # the result in a second limb vector.
+
+ # Copyright (C) 1992, 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 r16
+ # s1_ptr r17
+ # size r18
+ # s2_limb r19
+
+ # This code runs at 42 cycles/limb on the EV4 and 18 cycles/limb on the EV5.
+
+ # To improve performance for long multiplications, we would use
+ # 'fetch' for S1 and 'fetch_m' for RES. It's not obvious how to use
+ # these instructions without slowing down the general code: 1. We can
+ # only have two prefetches in operation at any time in the Alpha
+ # architecture. 2. There will seldom be any special alignment
+ # between RES_PTR and S1_PTR. Maybe we can simply divide the current
+ # loop into an inner and outer loop, having the inner loop handle
+ # exactly one prefetch block?
+
+ .set noreorder
+ .set noat
+.text
+ .align 3
+ .globl __mpn_mul_1
+ .ent __mpn_mul_1 2
+__mpn_mul_1:
+ .frame $30,0,$26
+
+ ldq $2,0($17) # $2 = s1_limb
+ subq $18,1,$18 # size--
+ mulq $2,$19,$3 # $3 = prod_low
+ bic $31,$31,$4 # clear cy_limb
+ umulh $2,$19,$0 # $0 = prod_high
+ beq $18,Lend1 # jump if size was == 1
+ ldq $2,8($17) # $2 = s1_limb
+ subq $18,1,$18 # size--
+ stq $3,0($16)
+ beq $18,Lend2 # jump if size was == 2
+
+ .align 3
+Loop: mulq $2,$19,$3 # $3 = prod_low
+ addq $4,$0,$0 # cy_limb = cy_limb + 'cy'
+ subq $18,1,$18 # size--
+ umulh $2,$19,$4 # $4 = cy_limb
+ ldq $2,16($17) # $2 = s1_limb
+ addq $17,8,$17 # s1_ptr++
+ addq $3,$0,$3 # $3 = cy_limb + prod_low
+ stq $3,8($16)
+ cmpult $3,$0,$0 # $0 = carry from (cy_limb + prod_low)
+ addq $16,8,$16 # res_ptr++
+ bne $18,Loop
+
+Lend2: mulq $2,$19,$3 # $3 = prod_low
+ addq $4,$0,$0 # cy_limb = cy_limb + 'cy'
+ umulh $2,$19,$4 # $4 = cy_limb
+ addq $3,$0,$3 # $3 = cy_limb + prod_low
+ cmpult $3,$0,$0 # $0 = carry from (cy_limb + prod_low)
+ stq $3,8($16)
+ addq $4,$0,$0 # cy_limb = prod_high + cy
+ ret $31,($26),1
+Lend1: stq $3,0($16)
+ ret $31,($26),1
+
+ .end __mpn_mul_1