dnl PowerPC-32/VMX and PowerPC-64/VMX mpn_popcount.
dnl Copyright 2006, 2010 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 7400,7410 (G4): ?
C 744x,745x (G4+): 1.125
C 970 (G5): 2.25
C TODO
C * Rewrite the awkward huge n outer loop code.
C * Two lvx, two vperm, and two vxor could make us a similar hamdist.
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')
define(`ap', `r3')
define(`n', `r4')
define(`rtab', `v10')
define(`cnt4', `v11')
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,toc)
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
LEAL( r11, cnsts)
li r12, 16
vspltisb cnt4, 4 C 0x0404...04 used as shift count
li r7, 160
lvx rtab, 0, r11
LIMB64(`lis r0, LIMBS_CHUNK_THRES ')
LIMB64(`cmpd cr7, n, r0 ')
lvx v0, 0, ap
addi r7, r11, 80
rlwinm r6, ap, 2,26,29
lvx v8, r7, r6
vand v0, v0, v8
LIMB32(`rlwinm r8, ap, 30,30,31 ')
LIMB64(`rlwinm r8, ap, 29,31,31 ')
add n, n, r8 C compensate n for rounded down `ap'
vxor v1, v1, v1
li r8, 0 C grand total count
vxor v12, v12, v12 C zero total count
vxor v13, v13, v13 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 ')
ALIGN(16)
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(16)
L(top):
lvx v0, 0, ap
L(ent): lvx v1, r12, ap
addi ap, ap, 32
vsrb v8, v0, cnt4
vsrb v9, v1, cnt4
vperm v2, rtab, rtab, v0
vperm v3, rtab, rtab, v8
vperm v4, rtab, rtab, v1
vperm v5, rtab, rtab, v9
vaddubm v6, v2, v3
vaddubm v7, v4, v5
vsum4ubs v12, v6, v12
vsum4ubs v13, v7, v13
bdnz L(top)
andi. n, n, eval(LIMBS_PER_2VR-1)
beq L(rt)
lvx v0, 0, ap
vxor v1, v1, v1
cmpwi n, LIMBS_PER_VR
ble L(sum)
L(lsum):
vor v1, v0, v0
lvx v0, r12, ap
L(sum):
LIMB32(`rlwinm r6, n, 4,26,27 ')
LIMB64(`rlwinm r6, n, 5,26,26 ')
addi r7, r11, 16
lvx v8, r7, r6
vand v0, v0, v8
vsrb v8, v0, cnt4
vsrb v9, v1, cnt4
vperm v2, rtab, rtab, v0
vperm v3, rtab, rtab, v8
vperm v4, rtab, rtab, v1
vperm v5, rtab, rtab, v9
vaddubm v6, v2, v3
vaddubm v7, v4, v5
vsum4ubs v12, v6, v12
vsum4ubs v13, v7, v13
ALIGN(16)
L(rt): vadduwm v3, v12, v13
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 v12, v12, v12 C zero total count
vxor v13, v13, v13 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)
')
ALIGN(16)
L(ret): mr r3, r8
mtspr 256, r10
blr
EPILOGUE()
DEF_OBJECT(cnsts,16)
C Counts for vperm
.byte 0x00,0x01,0x01,0x02,0x01,0x02,0x02,0x03
.byte 0x01,0x02,0x02,0x03,0x02,0x03,0x03,0x04
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()