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author | Zack Weinberg <zackw@panix.com> | 2017-06-08 15:39:03 -0400 |
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committer | Zack Weinberg <zackw@panix.com> | 2017-06-08 15:39:03 -0400 |
commit | 5046dbb4a7eba5eccfd258f92f4735c9ffc8d069 (patch) | |
tree | 4470480d904b65cf14ca524f96f79eca818c3eaf /REORG.TODO/sysdeps/alpha/rshift.S | |
parent | 199fc19d3aaaf57944ef036e15904febe877fc93 (diff) | |
download | glibc-5046dbb4a7eba5eccfd258f92f4735c9ffc8d069.tar.gz glibc-5046dbb4a7eba5eccfd258f92f4735c9ffc8d069.tar.xz glibc-5046dbb4a7eba5eccfd258f92f4735c9ffc8d069.zip |
Prepare for radical source tree reorganization. zack/build-layout-experiment
All top-level files and directories are moved into a temporary storage directory, REORG.TODO, except for files that will certainly still exist in their current form at top level when we're done (COPYING, COPYING.LIB, LICENSES, NEWS, README), all old ChangeLog files (which are moved to the new directory OldChangeLogs, instead), and the generated file INSTALL (which is just deleted; in the new order, there will be no generated files checked into version control).
Diffstat (limited to 'REORG.TODO/sysdeps/alpha/rshift.S')
-rw-r--r-- | REORG.TODO/sysdeps/alpha/rshift.S | 105 |
1 files changed, 105 insertions, 0 deletions
diff --git a/REORG.TODO/sysdeps/alpha/rshift.S b/REORG.TODO/sysdeps/alpha/rshift.S new file mode 100644 index 0000000000..65db71c2c9 --- /dev/null +++ b/REORG.TODO/sysdeps/alpha/rshift.S @@ -0,0 +1,105 @@ + # Alpha 21064 __mpn_rshift -- + + # Copyright (C) 1994-2017 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 Lesser General Public License as published by + # the Free Software Foundation; either version 2.1 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 Lesser General Public + # License for more details. + + # You should have received a copy of the GNU Lesser General Public License + # along with the GNU MP Library. If not, see <http://www.gnu.org/licenses/>. + + + # INPUT PARAMETERS + # res_ptr r16 + # s1_ptr r17 + # size r18 + # cnt r19 + + # This code runs at 4.8 cycles/limb on the 21064. With infinite unrolling, + # it would take 4 cycles/limb. It should be possible to get down to 3 + # cycles/limb since both ldq and stq can be paired with the other used + # instructions. But there are many restrictions in the 21064 pipeline that + # makes it hard, if not impossible, to get down to 3 cycles/limb: + + # 1. ldq has a 3 cycle delay, srl and sll have a 2 cycle delay. + # 2. Only aligned instruction pairs can be paired. + # 3. The store buffer or silo might not be able to deal with the bandwidth. + + .set noreorder + .set noat +.text + .align 3 + .globl __mpn_rshift + .ent __mpn_rshift +__mpn_rshift: + .frame $30,0,$26,0 + + ldq $4,0($17) # load first limb + addq $17,8,$17 + subq $31,$19,$7 + subq $18,1,$18 + and $18,4-1,$20 # number of limbs in first loop + sll $4,$7,$0 # compute function result + + beq $20,.L0 + subq $18,$20,$18 + + .align 3 +.Loop0: + ldq $3,0($17) + addq $16,8,$16 + addq $17,8,$17 + subq $20,1,$20 + srl $4,$19,$5 + sll $3,$7,$6 + bis $3,$3,$4 + bis $5,$6,$8 + stq $8,-8($16) + bne $20,.Loop0 + +.L0: beq $18,.Lend + + .align 3 +.Loop: ldq $3,0($17) + addq $16,32,$16 + subq $18,4,$18 + srl $4,$19,$5 + sll $3,$7,$6 + + ldq $4,8($17) + srl $3,$19,$1 + bis $5,$6,$8 + stq $8,-32($16) + sll $4,$7,$2 + + ldq $3,16($17) + srl $4,$19,$5 + bis $1,$2,$8 + stq $8,-24($16) + sll $3,$7,$6 + + ldq $4,24($17) + srl $3,$19,$1 + bis $5,$6,$8 + stq $8,-16($16) + sll $4,$7,$2 + + addq $17,32,$17 + bis $1,$2,$8 + stq $8,-8($16) + + bgt $18,.Loop + +.Lend: srl $4,$19,$8 + stq $8,0($16) + ret $31,($26),1 + .end __mpn_rshift |