dnl PowerPC-32/VMX and PowerPC-64/VMX mpn_popcount.
dnl Copyright 2006 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
dnl by the Free Software Foundation; either version 3 of the License, or (at
dnl your 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. If not, see http://www.gnu.org/licenses/.
include(`../config.m4')
C cycles/limb
C 7400,7410 (G4): 2.75
C 744x,745x (G4+): 2.25
C 970 (G5): 5.3
C STATUS
C * Works for all sizes and alignments.
C TODO
C * Tune the awkward huge n outer loop code.
C * Two lvx, two vperm, and two vxor could make us a similar hamdist.
C * For the 970, a combined VMX+intop approach might be best.
C * Compress cnsts table in 64-bit mode, only half the values are needed.
define(`GMP_LIMB_BYTES', eval(GMP_LIMB_BITS/8))
define(`LIMBS_PER_VR', eval(16/GMP_LIMB_BYTES))
define(`LIMBS_PER_2VR', eval(32/GMP_LIMB_BYTES))
define(`OPERATION_popcount')
ifdef(`OPERATION_popcount',`
define(`func',`mpn_popcount')
define(`up', `r3')
define(`n', `r4')
define(`HAM', `dnl')
')
ifdef(`OPERATION_hamdist',`
define(`func',`mpn_hamdist')
define(`up', `r3')
define(`vp', `r4')
define(`n', `r5')
define(`HAM', `$1')
')
define(`x01010101',`v2')
define(`x00110011',`v7')
define(`x00001111',`v10')
define(`cnt1',`v11')
define(`cnt2',`v12')
define(`cnt4',`v13')
ifelse(GMP_LIMB_BITS,32,`
define(`LIMB32',` $1')
define(`LIMB64',`')
',`
define(`LIMB32',`')
define(`LIMB64',` $1')
')
C The inner loop handles up to 2^34 bits, i.e., 2^31 64-limbs, due to overflow
C in vsum4ubs. For large operands, we work in chunks, of size LIMBS_PER_CHUNK.
define(`LIMBS_PER_CHUNK', 0x1000)
define(`LIMBS_CHUNK_THRES', 0x1001)
ASM_START()
PROLOGUE(mpn_popcount)
mfspr r10, 256
oris r0, r10, 0xfffc C Set VRSAVE bit 0-13
mtspr 256, r0
ifdef(`HAVE_ABI_mode32',
` rldicl n, n, 0, 32') C zero extend n
C Load various constants into vector registers
LEA( r11, cnsts)
li r12, 16
vspltisb cnt1, 1 C 0x0101...01 used as shift count
vspltisb cnt2, 2 C 0x0202...02 used as shift count
vspltisb cnt4, 4 C 0x0404...04 used as shift count
lvx x01010101, 0, r11 C 0x3333...33
lvx x00110011, r12, r11 C 0x5555...55
vspltisb x00001111, 15 C 0x0f0f...0f
LIMB64(`lis r0, LIMBS_CHUNK_THRES ')
LIMB64(`cmpd cr7, n, r0 ')
lvx v0, 0, up
addi r7, r11, 96
rlwinm r6, up, 2,26,29
lvx v8, r7, r6
vand v0, v0, v8
LIMB32(`rlwinm r8, up, 30,30,31 ')
LIMB64(`rlwinm r8, up, 29,31,31 ')
add n, n, r8 C compensate n for rounded down `up'
vxor v1, v1, v1
li r8, 0 C grand total count
vxor v3, v3, v3 C zero total count
addic. n, n, -LIMBS_PER_VR
ble L(sum)
addic. n, n, -LIMBS_PER_VR
ble L(lsum)
C For 64-bit machines, handle huge n that would overflow vsum4ubs
LIMB64(`ble cr7, L(small) ')
LIMB64(`addis r9, n, -LIMBS_PER_CHUNK ') C remaining n
LIMB64(`lis n, LIMBS_PER_CHUNK ')
L(small):
LIMB32(`srwi r7, n, 3 ') C loop count corresponding to n
LIMB64(`srdi r7, n, 2 ') C loop count corresponding to n
addi r7, r7, 1
mtctr r7 C copy n to count register
b L(ent)
ALIGN(8)
L(top): lvx v0, 0, up
li r7, 128 C prefetch distance
L(ent): lvx v1, r12, up
addi up, up, 32
vsr v4, v0, cnt1
vsr v5, v1, cnt1
dcbt up, r7 C prefetch
vand v8, v4, x01010101
vand v9, v5, x01010101
vsububm v0, v0, v8 C 64 2-bit accumulators (0..2)
vsububm v1, v1, v9 C 64 2-bit accumulators (0..2)
vsr v4, v0, cnt2
vsr v5, v1, cnt2
vand v8, v0, x00110011
vand v9, v1, x00110011
vand v4, v4, x00110011
vand v5, v5, x00110011
vaddubm v0, v4, v8 C 32 4-bit accumulators (0..4)
vaddubm v1, v5, v9 C 32 4-bit accumulators (0..4)
vaddubm v8, v0, v1 C 32 4-bit accumulators (0..8)
vsr v9, v8, cnt4
vand v6, v8, x00001111
vand v9, v9, x00001111
vaddubm v6, v9, v6 C 16 8-bit accumulators (0..16)
vsum4ubs v3, v6, v3 C sum 4 x 4 bytes into 4 32-bit fields
bdnz L(top)
andi. n, n, eval(LIMBS_PER_2VR-1)
beq L(rt)
lvx v0, 0, up
vxor v1, v1, v1
cmpwi n, LIMBS_PER_VR
ble L(sum)
L(lsum):
vor v1, v0, v0
lvx v0, r12, up
L(sum):
LIMB32(`rlwinm r6, n, 4,26,27 ')
LIMB64(`rlwinm r6, n, 5,26,26 ')
addi r7, r11, 32
lvx v8, r7, r6
vand v0, v0, v8
vsr v4, v0, cnt1
vsr v5, v1, cnt1
vand v8, v4, x01010101
vand v9, v5, x01010101
vsububm v0, v0, v8 C 64 2-bit accumulators (0..2)
vsububm v1, v1, v9 C 64 2-bit accumulators (0..2)
vsr v4, v0, cnt2
vsr v5, v1, cnt2
vand v8, v0, x00110011
vand v9, v1, x00110011
vand v4, v4, x00110011
vand v5, v5, x00110011
vaddubm v0, v4, v8 C 32 4-bit accumulators (0..4)
vaddubm v1, v5, v9 C 32 4-bit accumulators (0..4)
vaddubm v8, v0, v1 C 32 4-bit accumulators (0..8)
vsr v9, v8, cnt4
vand v6, v8, x00001111
vand v9, v9, x00001111
vaddubm v6, v9, v6 C 16 8-bit accumulators (0..16)
vsum4ubs v3, v6, v3 C sum 4 x 4 bytes into 4 32-bit fields
L(rt):
li r7, -16 C FIXME: does all ppc32 and ppc64 ABIs
stvx v3, r7, r1 C FIXME: ...support storing below sp?
lwz r7, -16(r1)
add r8, r8, r7
lwz r7, -12(r1)
add r8, r8, r7
lwz r7, -8(r1)
add r8, r8, r7
lwz r7, -4(r1)
add r8, r8, r7
C Handle outer loop for huge n. We inherit cr7 and r0 from above.
LIMB64(`ble cr7, L(ret)
vxor v3, v3, v3 C zero total count
mr n, r9
cmpd cr7, n, r0
ble cr7, L(2)
addis r9, n, -LIMBS_PER_CHUNK C remaining n
lis n, LIMBS_PER_CHUNK
L(2): srdi r7, n, 2 C loop count corresponding to n
mtctr r7 C copy n to count register
b L(top)
')
L(ret): mr r3, r8
mtspr 256, r10
blr
EPILOGUE()
DEF_OBJECT(cnsts,16)
.byte 0x55,0x55,0x55,0x55,0x55,0x55,0x55,0x55
.byte 0x55,0x55,0x55,0x55,0x55,0x55,0x55,0x55
.byte 0x33,0x33,0x33,0x33,0x33,0x33,0x33,0x33
.byte 0x33,0x33,0x33,0x33,0x33,0x33,0x33,0x33
C Masks for high end of number
.byte 0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff
.byte 0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff
.byte 0xff,0xff,0xff,0xff,0x00,0x00,0x00,0x00
.byte 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00
.byte 0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff
.byte 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00
.byte 0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff
.byte 0xff,0xff,0xff,0xff,0x00,0x00,0x00,0x00
C Masks for low end of number
.byte 0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff
.byte 0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff
.byte 0x00,0x00,0x00,0x00,0xff,0xff,0xff,0xff
.byte 0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff
.byte 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00
.byte 0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff
.byte 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00
.byte 0x00,0x00,0x00,0x00,0xff,0xff,0xff,0xff
END_OBJECT(cnsts)
ASM_END()
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