1 ; HP-PA-1.1 __gmpn_submul_1 -- Multiply a limb vector with a limb and
2 ; subtract the result from a second limb vector.
4 ; Copyright (C) 1992, 1993, 1994, 2000 Free Software Foundation, Inc.
6 ; This file is part of the GNU MP Library.
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15 ; or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
16 ; License for more details.
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30 ; This runs at 12 cycles/limb on a PA7000. With the used instructions, it
31 ; can not become faster due to data cache contention after a store. On the
32 ; PA7100 it runs at 11 cycles/limb, and that can not be improved either,
33 ; since only the xmpyu does not need the integer pipeline, so the only
34 ; dual-issue we will get are addc+xmpyu. Unrolling could gain a cycle/limb
37 ; There are some ideas described in mul_1.s that applies to this code too.
39 ; It seems possible to make this run as fast as __gmpn_addmul_1, if we use
40 ; sub,>>= %r29,%r19,%r22
42 ; but that requires reworking the hairy software pipeline...
45 .export __gmpn_submul_1
48 .callinfo frame=64,no_calls
53 stw %r23,-16(%r30) ; move s2_limb ...
54 addib,= -1,%r24,L$just_one_limb
55 fldws -16(%r30),%fr4 ; ... into fr4
56 add %r0,%r0,%r0 ; clear carry
61 ldw -12(%r30),%r19 ; least significant limb in product
69 L$loop ldws 0(%r26),%r29
79 addib,<> -1,%r24,L$loop
82 L$end ldw 0(%r26),%r29