dnl Alpha ev6 mpn_add_n -- Add two limb vectors of the same length > 0 and
dnl store sum in a third limb vector.
dnl Copyright 2000, 2003, 2005 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 EV4: ?
C EV5: 5.4
C EV6: 2.125
C INPUT PARAMETERS
C rp r16
C up r17
C vp r18
C n r19
C cy r20 (for mpn_add_nc)
C TODO
C Finish cleaning up cy registers r22, r23 (make them use cy0/cy1)
C Use multi-pronged feed-in.
C Perform additional micro-tuning
C This code was written in cooperation with ev6 pipeline expert Steve Root.
C Pair loads and stores where possible
C Store pairs oct-aligned where possible (didn't need it here)
C Stores are delayed every third cycle
C Loads and stores are delayed by fills
C U stays still, put code there where possible (note alternation of U1 and U0)
C L moves because of loads and stores
C Note dampers in L to limit damage
C This odd-looking optimization expects that were having random bits in our
C data, so that a pure zero result is unlikely. so we penalize the unlikely
C case to help the common case.
define(`u0', `r0') define(`u1', `r3')
define(`v0', `r1') define(`v1', `r4')
define(`cy0', `r20') define(`cy1', `r21')
MULFUNC_PROLOGUE(mpn_add_n mpn_add_nc)
ASM_START()
PROLOGUE(mpn_add_nc)
br r31, $entry
EPILOGUE()
PROLOGUE(mpn_add_n)
bis r31, r31, cy0 C clear carry in
$entry: cmpult r19, 5, r22 C L1 move counter
ldq u1, 0(r17) C L0 get next ones
ldq v1, 0(r18) C L1
bne r22, $Lsmall
ldq u0, 8(r17) C L0 get next ones
ldq v0, 8(r18) C L1
addq u1, v1, r5 C U0 add two data
cmpult r5, v1, r23 C U0 did it carry
ldq u1, 16(r17) C L0 get next ones
ldq v1, 16(r18) C L1
addq u0, v0, r8 C U1 add two data
addq r5, cy0, r5 C U0 carry in
cmpult r8, v0, r22 C U1 did it carry
beq r5, $fix5f C U0 fix exact zero
$ret5f: ldq u0, 24(r17) C L0 get next ones
ldq v0, 24(r18) C L1
addq r8, r23, r8 C U1 carry from last
addq u1, v1, r7 C U0 add two data
beq r8, $fix6f C U1 fix exact zero
$ret6f: cmpult r7, v1, r23 C U0 did it carry
ldq u1, 32(r17) C L0 get next ones
ldq v1, 32(r18) C L1
lda r17, 40(r17) C L0 move pointer
lda r18, 40(r18) C L1 move pointer
lda r16, -8(r16)
lda r19, -13(r19) C L1 move counter
blt r19, $Lend C U1 loop control
C Main loop. 8-way unrolled.
ALIGN(16)
$Loop: addq u0, v0, r2 C U1 add two data
addq r7, r22, r7 C U0 add in carry
stq r5, 8(r16) C L0 put an answer
stq r8, 16(r16) C L1 pair
cmpult r2, v0, cy1 C U1 did it carry
beq r7, $fix7 C U0 fix exact 0
$ret7: ldq u0, 0(r17) C L0 get next ones
ldq v0, 0(r18) C L1
bis r31, r31, r31 C L damp out
addq r2, r23, r2 C U1 carry from last
bis r31, r31, r31 C L moves in L !
addq u1, v1, r5 C U0 add two data
beq r2, $fix0 C U1 fix exact zero
$ret0: cmpult r5, v1, cy0 C U0 did it carry
ldq u1, 8(r17) C L0 get next ones
ldq v1, 8(r18) C L1
addq u0, v0, r8 C U1 add two data
addq r5, cy1, r5 C U0 carry from last
stq r7, 24(r16) C L0 store pair
stq r2, 32(r16) C L1
cmpult r8, v0, r22 C U1 did it carry
beq r5, $fix1 C U0 fix exact zero
$ret1: ldq u0, 16(r17) C L0 get next ones
ldq v0, 16(r18) C L1
lda r16, 64(r16) C L0 move pointer
addq r8, cy0, r8 C U1 carry from last
lda r19, -8(r19) C L1 move counter
addq u1, v1, r7 C U0 add two data
beq r8, $fix2 C U1 fix exact zero
$ret2: cmpult r7, v1, r23 C U0 did it carry
ldq u1, 24(r17) C L0 get next ones
ldq v1, 24(r18) C L1
addq u0, v0, r2 C U1 add two data
addq r7, r22, r7 C U0 add in carry
stq r5, -24(r16) C L0 put an answer
stq r8, -16(r16) C L1 pair
cmpult r2, v0, cy1 C U1 did it carry
beq r7, $fix3 C U0 fix exact 0
$ret3: ldq u0, 32(r17) C L0 get next ones
ldq v0, 32(r18) C L1
bis r31, r31, r31 C L damp out
addq r2, r23, r2 C U1 carry from last
bis r31, r31, r31 C L moves in L !
addq u1, v1, r5 C U0 add two data
beq r2, $fix4 C U1 fix exact zero
$ret4: cmpult r5, v1, cy0 C U0 did it carry
ldq u1, 40(r17) C L0 get next ones
ldq v1, 40(r18) C L1
addq u0, v0, r8 C U1 add two data
addq r5, cy1, r5 C U0 carry from last
stq r7, -8(r16) C L0 store pair
stq r2, 0(r16) C L1
cmpult r8, v0, r22 C U1 did it carry
beq r5, $fix5 C U0 fix exact zero
$ret5: ldq u0, 48(r17) C L0 get next ones
ldq v0, 48(r18) C L1
ldl r31, 256(r17) C L0 prefetch
addq r8, cy0, r8 C U1 carry from last
ldl r31, 256(r18) C L1 prefetch
addq u1, v1, r7 C U0 add two data
beq r8, $fix6 C U1 fix exact zero
$ret6: cmpult r7, v1, r23 C U0 did it carry
ldq u1, 56(r17) C L0 get next ones
ldq v1, 56(r18) C L1
lda r17, 64(r17) C L0 move pointer
bis r31, r31, r31 C U
lda r18, 64(r18) C L1 move pointer
bge r19, $Loop C U1 loop control
C ==== main loop end
$Lend: addq u0, v0, r2 C U1 add two data
addq r7, r22, r7 C U0 add in carry
stq r5, 8(r16) C L0 put an answer
stq r8, 16(r16) C L1 pair
cmpult r2, v0, cy1 C U1 did it carry
beq r7, $fix7c C U0 fix exact 0
$ret7c: addq r2, r23, r2 C U1 carry from last
addq u1, v1, r5 C U0 add two data
beq r2, $fix0c C U1 fix exact zero
$ret0c: cmpult r5, v1, cy0 C U0 did it carry
addq r5, cy1, r5 C U0 carry from last
stq r7, 24(r16) C L0 store pair
stq r2, 32(r16) C L1
beq r5, $fix1c C U0 fix exact zero
$ret1c: stq r5, 40(r16) C L0 put an answer
lda r16, 48(r16) C L0 move pointer
lda r19, 8(r19)
beq r19, $Lret
ldq u1, 0(r17)
ldq v1, 0(r18)
$Lsmall:
lda r19, -1(r19)
beq r19, $Lend0
ALIGN(8)
$Loop0: addq u1, v1, r2 C main add
cmpult r2, v1, r8 C compute cy from last add
ldq u1, 8(r17)
ldq v1, 8(r18)
addq r2, cy0, r5 C carry add
lda r17, 8(r17)
lda r18, 8(r18)
stq r5, 0(r16)
cmpult r5, r2, cy0 C compute cy from last add
lda r19, -1(r19) C decr loop cnt
bis r8, cy0, cy0 C combine cy from the two adds
lda r16, 8(r16)
bne r19, $Loop0
$Lend0: addq u1, v1, r2 C main add
addq r2, cy0, r5 C carry add
cmpult r2, v1, r8 C compute cy from last add
cmpult r5, r2, cy0 C compute cy from last add
stq r5, 0(r16)
bis r8, cy0, r0 C combine cy from the two adds
ret r31,(r26),1
ALIGN(8)
$Lret: lda r0, 0(cy0) C copy carry into return register
ret r31,(r26),1
$fix5f: bis r23, cy0, r23 C bring forward carry
br r31, $ret5f
$fix6f: bis r22, r23, r22 C bring forward carry
br r31, $ret6f
$fix0: bis cy1, r23, cy1 C bring forward carry
br r31, $ret0
$fix1: bis cy0, cy1, cy0 C bring forward carry
br r31, $ret1
$fix2: bis r22, cy0, r22 C bring forward carry
br r31, $ret2
$fix3: bis r23, r22, r23 C bring forward carry
br r31, $ret3
$fix4: bis cy1, r23, cy1 C bring forward carry
br r31, $ret4
$fix5: bis cy1, cy0, cy0 C bring forward carry
br r31, $ret5
$fix6: bis r22, cy0, r22 C bring forward carry
br r31, $ret6
$fix7: bis r23, r22, r23 C bring forward carry
br r31, $ret7
$fix0c: bis cy1, r23, cy1 C bring forward carry
br r31, $ret0c
$fix1c: bis cy0, cy1, cy0 C bring forward carry
br r31, $ret1c
$fix7c: bis r23, r22, r23 C bring forward carry
br r31, $ret7c
EPILOGUE()
ASM_END()