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Diffstat (limited to 'rts/gmp/mpn/alpha/rshift.asm')
| -rw-r--r-- | rts/gmp/mpn/alpha/rshift.asm | 102 |
1 files changed, 102 insertions, 0 deletions
diff --git a/rts/gmp/mpn/alpha/rshift.asm b/rts/gmp/mpn/alpha/rshift.asm new file mode 100644 index 0000000000..aa25eda54e --- /dev/null +++ b/rts/gmp/mpn/alpha/rshift.asm @@ -0,0 +1,102 @@ +dnl Alpha mpn_rshift -- Shift a number right. + +dnl Copyright (C) 1994, 1995, 2000 Free Software Foundation, Inc. + +dnl This file is part of the GNU MP Library. + +dnl The GNU MP Library is free software; you can redistribute it and/or modify +dnl it under the terms of the GNU Lesser General Public License as published by +dnl the Free Software Foundation; either version 2.1 of the License, or (at your +dnl option) any later version. + +dnl The GNU MP Library is distributed in the hope that it will be useful, but +dnl WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY +dnl or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public +dnl License for more details. + +dnl You should have received a copy of the GNU Lesser General Public License +dnl along with the GNU MP Library; see the file COPYING.LIB. If not, write to +dnl the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, +dnl MA 02111-1307, USA. + +include(`../config.m4') + +dnl INPUT PARAMETERS +dnl res_ptr r16 +dnl s1_ptr r17 +dnl size r18 +dnl cnt r19 + +dnl This code runs at 4.8 cycles/limb on the 21064. With infinite unrolling, +dnl it would take 4 cycles/limb. It should be possible to get down to 3 +dnl cycles/limb since both ldq and stq can be paired with the other used +dnl instructions. But there are many restrictions in the 21064 pipeline that +dnl makes it hard, if not impossible, to get down to 3 cycles/limb: + +dnl 1. ldq has a 3 cycle delay, srl and sll have a 2 cycle delay. +dnl 2. Only aligned instruction pairs can be paired. +dnl 3. The store buffer or silo might not be able to deal with the bandwidth. + +ASM_START() +PROLOGUE(mpn_rshift) + ldq r4,0(r17) C load first limb + addq r17,8,r17 + subq r31,r19,r7 + subq r18,1,r18 + and r18,4-1,r20 C number of limbs in first loop + sll r4,r7,r0 C compute function result + + beq r20,$L0 + subq r18,r20,r18 + + ALIGN(8) +$Loop0: + ldq r3,0(r17) + addq r16,8,r16 + addq r17,8,r17 + subq r20,1,r20 + srl r4,r19,r5 + sll r3,r7,r6 + bis r3,r3,r4 + bis r5,r6,r8 + stq r8,-8(r16) + bne r20,$Loop0 + +$L0: beq r18,$Lend + + ALIGN(8) +$Loop: ldq r3,0(r17) + addq r16,32,r16 + subq r18,4,r18 + srl r4,r19,r5 + sll r3,r7,r6 + + ldq r4,8(r17) + srl r3,r19,r1 + bis r5,r6,r8 + stq r8,-32(r16) + sll r4,r7,r2 + + ldq r3,16(r17) + srl r4,r19,r5 + bis r1,r2,r8 + stq r8,-24(r16) + sll r3,r7,r6 + + ldq r4,24(r17) + srl r3,r19,r1 + bis r5,r6,r8 + stq r8,-16(r16) + sll r4,r7,r2 + + addq r17,32,r17 + bis r1,r2,r8 + stq r8,-8(r16) + + bgt r18,$Loop + +$Lend: srl r4,r19,r8 + stq r8,0(r16) + ret r31,(r26),1 +EPILOGUE(mpn_rshift) +ASM_END() |