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authorTorbjorn Granlund <tg@gmplib.org>2017-02-11 04:12:10 +0100
committerTorbjorn Granlund <tg@gmplib.org>2017-02-11 04:12:10 +0100
commit7e569b64bdb96d70737fc3fda7818c719a00857f (patch)
tree1545ae94af43ef5448577ced935fafa3678711fc /mpn/arm
parent9556cf5c966a8ee8062ff7ac15adb369f7b9c4f6 (diff)
downloadgmp-7e569b64bdb96d70737fc3fda7818c719a00857f.tar.gz
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-rw-r--r--mpn/arm/bdiv_q_1.asm162
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diff --git a/mpn/arm/bdiv_q_1.asm b/mpn/arm/bdiv_q_1.asm
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+dnl ARM v4 mpn_bdiv_q_1, mpn_pi1_bdiv_q_1 -- Hensel division by 1-limb divisor.
+
+dnl Contributed to the GNU project by Torbjörn Granlund.
+
+dnl Copyright 2012, 2017 Free Software Foundation, Inc.
+
+dnl This file is part of the GNU MP Library.
+dnl
+dnl The GNU MP Library is free software; you can redistribute it and/or modify
+dnl it under the terms of either:
+dnl
+dnl * the GNU Lesser General Public License as published by the Free
+dnl Software Foundation; either version 3 of the License, or (at your
+dnl option) any later version.
+dnl
+dnl or
+dnl
+dnl * the GNU General Public License as published by the Free Software
+dnl Foundation; either version 2 of the License, or (at your option) any
+dnl later version.
+dnl
+dnl or both in parallel, as here.
+dnl
+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 General Public License
+dnl for more details.
+dnl
+dnl You should have received copies of the GNU General Public License and the
+dnl GNU Lesser General Public License along with the GNU MP Library. If not,
+dnl see https://www.gnu.org/licenses/.
+
+include(`../config.m4')
+
+C cycles/limb
+C norm unorm
+C 1176 13 18
+C Cortex-A5 8 12
+C Cortex-A7 10.5 18
+C Cortex-A8 14 15
+C Cortex-A9 10 12 not measured since latest edits
+C Cortex-A15 9 9
+C Cortex-A53 14 20
+
+C Architecture requirements:
+C v5 -
+C v5t -
+C v5te -
+C v6 -
+C v6t2 -
+C v7a -
+
+define(`rp', `r0')
+define(`up', `r1')
+define(`n', `r2')
+define(`d', `r3')
+define(`di_arg', `sp[0]') C just mpn_pi1_bdiv_q_1
+define(`cnt_arg', `sp[4]') C just mpn_pi1_bdiv_q_1
+
+define(`cy', `r7')
+define(`cnt', `r6')
+define(`tnc', `r8')
+
+ASM_START()
+PROLOGUE(mpn_bdiv_q_1)
+ tst d, #1
+ push {r6-r11}
+ mov cnt, #0
+ bne L(inv)
+
+C count trailing zeros
+ movs r10, d, lsl #16
+ moveq d, d, lsr #16
+ moveq cnt, #16
+ tst d, #0xff
+ moveq d, d, lsr #8
+ addeq cnt, cnt, #8
+ LEA( r10, ctz_tab)
+ and r11, d, #0xff
+ ldrb r10, [r10, r11]
+ mov d, d, lsr r10
+ adds cnt, cnt, r10
+
+C binvert limb
+L(inv): LEA( r10, binvert_limb_table)
+ and r12, d, #254
+ ldrb r10, [r10, r12, lsr #1]
+ mul r12, r10, r10
+ mul r12, d, r12
+ rsb r12, r12, r10, lsl #1
+ mul r10, r12, r12
+ mul r10, d, r10
+ rsb r10, r10, r12, lsl #1 C r10 = inverse
+ b L(pi1)
+EPILOGUE()
+
+PROLOGUE(mpn_pi1_bdiv_q_1)
+ push {r6-r11}
+
+ ldr cnt, [sp, #28]
+ ldr r10, [sp, #24]
+ cmp cnt, #0
+
+L(pi1): ldr r11, [up], #4 C up[0]
+ mov cy, #0
+ bne L(unorm)
+
+L(norm):
+ subs n, n, #1 C set carry as side-effect
+ beq L(edn)
+
+ ALIGN(16)
+L(tpn): sbcs cy, r11, cy
+ ldr r11, [up], #4
+ sub n, n, #1
+ mul r9, r10, cy
+ tst n, n
+ umull r12, cy, d, r9
+ str r9, [rp], #4
+ bne L(tpn)
+
+L(edn): sbc cy, r11, cy
+ mul r9, r10, cy
+ str r9, [rp]
+ pop {r6-r11}
+ return r14
+
+L(unorm):
+ rsb tnc, cnt, #32
+ mov r11, r11, lsr cnt
+ subs n, n, #1 C set carry as side-effect
+ beq L(edu)
+
+ ALIGN(16)
+L(tpu): ldr r12, [up], #4
+ orr r9, r11, r12, lsl tnc
+ mov r11, r12, lsr cnt
+ sbcs cy, r9, cy C critical path ->cy->cy->
+ sub n, n, #1
+ mul r9, r10, cy C critical path ->cy->r9->
+ tst n, n
+ umull r12, cy, d, r9 C critical path ->r9->cy->
+ str r9, [rp], #4
+ bne L(tpu)
+
+L(edu): sbc cy, r11, cy
+ mul r9, r10, cy
+ str r9, [rp]
+ pop {r6-r11}
+ return r14
+EPILOGUE()
+
+ RODATA
+ctz_tab:
+ .byte 8,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0
+ .byte 5,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0
+ .byte 6,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0
+ .byte 5,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0
+ .byte 7,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0
+ .byte 5,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0
+ .byte 6,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0
+ .byte 5,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0