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glibc/ports/sysdeps/alpha/alphaev6/addmul_1.S
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# Alpha ev6 mpn_addmul_1 -- Multiply a limb vector with a limb and add | |
# the result to a second limb vector. | |
# | |
# Copyright (C) 2000 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 $16 | |
# s1_ptr $17 | |
# size $18 | |
# s2_limb $19 | |
# | |
# This code runs at 42 cycles/limb on EV4, 18 cycles/limb on EV5, and | |
# exactly 3.625 cycles/limb on EV6... | |
# | |
# This code was written in close cooperation with ev6 pipeline expert | |
# Steve Root (root@toober.hlo.dec.com). Any errors are tege's fault, though. | |
# | |
# Register usages for unrolled loop: | |
# 0-3 mul's | |
# 4-7 acc's | |
# 8-15 mul results | |
# 20,21 carry's | |
# 22,23 save for stores | |
# | |
# Sustains 8 mul-adds in 29 cycles in the unrolled inner loop. | |
# | |
# The stores can issue a cycle late so we have paired no-op's to 'catch' | |
# them, so that further disturbance to the schedule is damped. | |
# | |
# We couldn't pair the loads, because the entangled schedule of the | |
# carry's has to happen on one side {0} of the machine. Note, the total | |
# use of U0, and the total use of L0 (after attending to the stores). | |
# which is part of the reason why.... | |
# | |
# This is a great schedule for the d_cache, a poor schedule for the | |
# b_cache. The lockup on U0 means that any stall can't be recovered | |
# from. Consider a ldq in L1. say that load gets stalled because it | |
# collides with a fill from the b_Cache. On the next cycle, this load | |
# gets priority. If first looks at L0, and goes there. The instruction | |
# we intended for L0 gets to look at L1, which is NOT where we want | |
# it. It either stalls 1, because it can't go in L0, or goes there, and | |
# causes a further instruction to stall. | |
# | |
# So for b_cache, we're likely going to want to put one or more cycles | |
# back into the code! And, of course, put in prefetches. For the | |
# accumulator, lds, intent to modify. For the multiplier, you might | |
# want ldq, evict next, if you're not wanting to use it again soon. Use | |
# 256 ahead of present pointer value. At a place where we have an mt | |
# followed by a bookkeeping, put the bookkeeping in upper, and the | |
# prefetch into lower. | |
# | |
# Note, the usage of physical registers per cycle is smoothed off, as | |
# much as possible. | |
# | |
# Note, the ldq's and stq's are at the end of the quadpacks. note, we'd | |
# like not to have a ldq or stq to preceded a conditional branch in a | |
# quadpack. The conditional branch moves the retire pointer one cycle | |
# later. | |
# | |
# Optimization notes: | |
# Callee-saves regs: $9 $10 $11 $12 $13 $14 $15 $26 ?$27? | |
# Reserved regs: $29 $30 $31 | |
# Free caller-saves regs in unrolled code: $24 $25 $28 | |
# We should swap some of the callee-saves regs for some of the free | |
# caller-saves regs, saving some overhead cycles. | |
# Most importantly, we should write fast code for the 0-7 case. | |
# The code we use there are for the 21164, and runs at 7 cycles/limb | |
# on the 21264. Should not be hard, if we write specialized code for | |
# 1-7 limbs (the one for 0 limbs should be straightforward). We then just | |
# need a jump table indexed by the low 3 bits of the count argument. | |
.set noreorder | |
.set noat | |
.text | |
.globl __mpn_addmul_1 | |
.ent __mpn_addmul_1 | |
__mpn_addmul_1: | |
.frame $30,0,$26,0 | |
.prologue 0 | |
cmpult $18, 8, $1 | |
beq $1, $Large | |
ldq $2, 0($17) # $2 = s1_limb | |
addq $17, 8, $17 # s1_ptr++ | |
subq $18, 1, $18 # size-- | |
mulq $2, $19, $3 # $3 = prod_low | |
ldq $5, 0($16) # $5 = *res_ptr | |
umulh $2, $19, $0 # $0 = prod_high | |
beq $18, $Lend0b # jump if size was == 1 | |
ldq $2, 0($17) # $2 = s1_limb | |
addq $17, 8, $17 # s1_ptr++ | |
subq $18, 1, $18 # size-- | |
addq $5, $3, $3 | |
cmpult $3, $5, $4 | |
stq $3, 0($16) | |
addq $16, 8, $16 # res_ptr++ | |
beq $18, $Lend0a # jump if size was == 2 | |
.align 3 | |
$Loop0: mulq $2, $19, $3 # $3 = prod_low | |
ldq $5, 0($16) # $5 = *res_ptr | |
addq $4, $0, $0 # cy_limb = cy_limb + 'cy' | |
subq $18, 1, $18 # size-- | |
umulh $2, $19, $4 # $4 = cy_limb | |
ldq $2, 0($17) # $2 = s1_limb | |
addq $17, 8, $17 # s1_ptr++ | |
addq $3, $0, $3 # $3 = cy_limb + prod_low | |
cmpult $3, $0, $0 # $0 = carry from (cy_limb + prod_low) | |
addq $5, $3, $3 | |
cmpult $3, $5, $5 | |
stq $3, 0($16) | |
addq $16, 8, $16 # res_ptr++ | |
addq $5, $0, $0 # combine carries | |
bne $18, $Loop0 | |
$Lend0a: | |
mulq $2, $19, $3 # $3 = prod_low | |
ldq $5, 0($16) # $5 = *res_ptr | |
addq $4, $0, $0 # cy_limb = cy_limb + 'cy' | |
umulh $2, $19, $4 # $4 = cy_limb | |
addq $3, $0, $3 # $3 = cy_limb + prod_low | |
cmpult $3, $0, $0 # $0 = carry from (cy_limb + prod_low) | |
addq $5, $3, $3 | |
cmpult $3, $5, $5 | |
stq $3, 0($16) | |
addq $5, $0, $0 # combine carries | |
addq $4, $0, $0 # cy_limb = prod_high + cy | |
ret $31, ($26), 1 | |
$Lend0b: | |
addq $5, $3, $3 | |
cmpult $3, $5, $5 | |
stq $3, 0($16) | |
addq $0, $5, $0 | |
ret $31, ($26), 1 | |
$Large: | |
lda $30, -240($30) | |
stq $9, 8($30) | |
stq $10, 16($30) | |
stq $11, 24($30) | |
stq $12, 32($30) | |
stq $13, 40($30) | |
stq $14, 48($30) | |
stq $15, 56($30) | |
and $18, 7, $20 # count for the first loop, 0-7 | |
srl $18, 3, $18 # count for unrolled loop | |
bis $31, $31, $0 | |
beq $20, $Lunroll | |
ldq $2, 0($17) # $2 = s1_limb | |
addq $17, 8, $17 # s1_ptr++ | |
subq $20, 1, $20 # size-- | |
mulq $2, $19, $3 # $3 = prod_low | |
ldq $5, 0($16) # $5 = *res_ptr | |
umulh $2, $19, $0 # $0 = prod_high | |
beq $20, $Lend1b # jump if size was == 1 | |
ldq $2, 0($17) # $2 = s1_limb | |
addq $17, 8, $17 # s1_ptr++ | |
subq $20, 1, $20 # size-- | |
addq $5, $3, $3 | |
cmpult $3, $5, $4 | |
stq $3, 0($16) | |
addq $16, 8, $16 # res_ptr++ | |
beq $20, $Lend1a # jump if size was == 2 | |
.align 3 | |
$Loop1: mulq $2, $19, $3 # $3 = prod_low | |
ldq $5, 0($16) # $5 = *res_ptr | |
addq $4, $0, $0 # cy_limb = cy_limb + 'cy' | |
subq $20, 1, $20 # size-- | |
umulh $2, $19, $4 # $4 = cy_limb | |
ldq $2, 0($17) # $2 = s1_limb | |
addq $17, 8, $17 # s1_ptr++ | |
addq $3, $0, $3 # $3 = cy_limb + prod_low | |
cmpult $3, $0, $0 # $0 = carry from (cy_limb + prod_low) | |
addq $5, $3, $3 | |
cmpult $3, $5, $5 | |
stq $3, 0($16) | |
addq $16, 8, $16 # res_ptr++ | |
addq $5, $0, $0 # combine carries | |
bne $20, $Loop1 | |
$Lend1a: | |
mulq $2, $19, $3 # $3 = prod_low | |
ldq $5, 0($16) # $5 = *res_ptr | |
addq $4, $0, $0 # cy_limb = cy_limb + 'cy' | |
umulh $2, $19, $4 # $4 = cy_limb | |
addq $3, $0, $3 # $3 = cy_limb + prod_low | |
cmpult $3, $0, $0 # $0 = carry from (cy_limb + prod_low) | |
addq $5, $3, $3 | |
cmpult $3, $5, $5 | |
stq $3, 0($16) | |
addq $16, 8, $16 # res_ptr++ | |
addq $5, $0, $0 # combine carries | |
addq $4, $0, $0 # cy_limb = prod_high + cy | |
br $31, $Lunroll | |
$Lend1b: | |
addq $5, $3, $3 | |
cmpult $3, $5, $5 | |
stq $3, 0($16) | |
addq $16, 8, $16 # res_ptr++ | |
addq $0, $5, $0 | |
$Lunroll: | |
lda $17, -16($17) # L1 bookkeeping | |
lda $16, -16($16) # L1 bookkeeping | |
bis $0, $31, $12 | |
# ____ UNROLLED LOOP SOFTWARE PIPELINE STARTUP ____ | |
ldq $2, 16($17) # L1 | |
ldq $3, 24($17) # L1 | |
lda $18, -1($18) # L1 bookkeeping | |
ldq $6, 16($16) # L1 | |
ldq $7, 24($16) # L1 | |
ldq $0, 32($17) # L1 | |
mulq $19, $2, $13 # U1 | |
ldq $1, 40($17) # L1 | |
umulh $19, $2, $14 # U1 | |
mulq $19, $3, $15 # U1 | |
lda $17, 64($17) # L1 bookkeeping | |
ldq $4, 32($16) # L1 | |
ldq $5, 40($16) # L1 | |
umulh $19, $3, $8 # U1 | |
ldq $2, -16($17) # L1 | |
mulq $19, $0, $9 # U1 | |
ldq $3, -8($17) # L1 | |
umulh $19, $0, $10 # U1 | |
addq $6, $13, $6 # L0 lo + acc | |
mulq $19, $1, $11 # U1 | |
cmpult $6, $13, $20 # L0 lo add => carry | |
lda $16, 64($16) # L1 bookkeeping | |
addq $6, $12, $22 # U0 hi add => answer | |
cmpult $22, $12, $21 # L0 hi add => carry | |
addq $14, $20, $14 # U0 hi mul + carry | |
ldq $6, -16($16) # L1 | |
addq $7, $15, $23 # L0 lo + acc | |
addq $14, $21, $14 # U0 hi mul + carry | |
ldq $7, -8($16) # L1 | |
umulh $19, $1, $12 # U1 | |
cmpult $23, $15, $20 # L0 lo add => carry | |
addq $23, $14, $23 # U0 hi add => answer | |
ldq $0, 0($17) # L1 | |
mulq $19, $2, $13 # U1 | |
cmpult $23, $14, $21 # L0 hi add => carry | |
addq $8, $20, $8 # U0 hi mul + carry | |
ldq $1, 8($17) # L1 | |
umulh $19, $2, $14 # U1 | |
addq $4, $9, $4 # L0 lo + acc | |
stq $22, -48($16) # L0 | |
stq $23, -40($16) # L1 | |
mulq $19, $3, $15 # U1 | |
addq $8, $21, $8 # U0 hi mul + carry | |
cmpult $4, $9, $20 # L0 lo add => carry | |
addq $4, $8, $22 # U0 hi add => answer | |
ble $18, $Lend # U1 bookkeeping | |
# ____ MAIN UNROLLED LOOP ____ | |
.align 4 | |
$Loop: | |
bis $31, $31, $31 # U1 mt | |
cmpult $22, $8, $21 # L0 hi add => carry | |
addq $10, $20, $10 # U0 hi mul + carry | |
ldq $4, 0($16) # L1 | |
bis $31, $31, $31 # U1 mt | |
addq $5, $11, $23 # L0 lo + acc | |
addq $10, $21, $10 # L0 hi mul + carry | |
ldq $5, 8($16) # L1 | |
umulh $19, $3, $8 # U1 | |
cmpult $23, $11, $20 # L0 lo add => carry | |
addq $23, $10, $23 # U0 hi add => answer | |
ldq $2, 16($17) # L1 | |
mulq $19, $0, $9 # U1 | |
cmpult $23, $10, $21 # L0 hi add => carry | |
addq $12, $20, $12 # U0 hi mul + carry | |
ldq $3, 24($17) # L1 | |
umulh $19, $0, $10 # U1 | |
addq $6, $13, $6 # L0 lo + acc | |
stq $22, -32($16) # L0 | |
stq $23, -24($16) # L1 | |
bis $31, $31, $31 # L0 st slosh | |
mulq $19, $1, $11 # U1 | |
bis $31, $31, $31 # L1 st slosh | |
addq $12, $21, $12 # U0 hi mul + carry | |
cmpult $6, $13, $20 # L0 lo add => carry | |
bis $31, $31, $31 # U1 mt | |
lda $18, -1($18) # L1 bookkeeping | |
addq $6, $12, $22 # U0 hi add => answer | |
bis $31, $31, $31 # U1 mt | |
cmpult $22, $12, $21 # L0 hi add => carry | |
addq $14, $20, $14 # U0 hi mul + carry | |
ldq $6, 16($16) # L1 | |
bis $31, $31, $31 # U1 mt | |
addq $7, $15, $23 # L0 lo + acc | |
addq $14, $21, $14 # U0 hi mul + carry | |
ldq $7, 24($16) # L1 | |
umulh $19, $1, $12 # U1 | |
cmpult $23, $15, $20 # L0 lo add => carry | |
addq $23, $14, $23 # U0 hi add => answer | |
ldq $0, 32($17) # L1 | |
mulq $19, $2, $13 # U1 | |
cmpult $23, $14, $21 # L0 hi add => carry | |
addq $8, $20, $8 # U0 hi mul + carry | |
ldq $1, 40($17) # L1 | |
umulh $19, $2, $14 # U1 | |
addq $4, $9, $4 # U0 lo + acc | |
stq $22, -16($16) # L0 | |
stq $23, -8($16) # L1 | |
bis $31, $31, $31 # L0 st slosh | |
mulq $19, $3, $15 # U1 | |
bis $31, $31, $31 # L1 st slosh | |
addq $8, $21, $8 # L0 hi mul + carry | |
cmpult $4, $9, $20 # L0 lo add => carry | |
bis $31, $31, $31 # U1 mt | |
lda $17, 64($17) # L1 bookkeeping | |
addq $4, $8, $22 # U0 hi add => answer | |
bis $31, $31, $31 # U1 mt | |
cmpult $22, $8, $21 # L0 hi add => carry | |
addq $10, $20, $10 # U0 hi mul + carry | |
ldq $4, 32($16) # L1 | |
bis $31, $31, $31 # U1 mt | |
addq $5, $11, $23 # L0 lo + acc | |
addq $10, $21, $10 # L0 hi mul + carry | |
ldq $5, 40($16) # L1 | |
umulh $19, $3, $8 # U1 | |
cmpult $23, $11, $20 # L0 lo add => carry | |
addq $23, $10, $23 # U0 hi add => answer | |
ldq $2, -16($17) # L1 | |
mulq $19, $0, $9 # U1 | |
cmpult $23, $10, $21 # L0 hi add => carry | |
addq $12, $20, $12 # U0 hi mul + carry | |
ldq $3, -8($17) # L1 | |
umulh $19, $0, $10 # U1 | |
addq $6, $13, $6 # L0 lo + acc | |
stq $22, 0($16) # L0 | |
stq $23, 8($16) # L1 | |
bis $31, $31, $31 # L0 st slosh | |
mulq $19, $1, $11 # U1 | |
bis $31, $31, $31 # L1 st slosh | |
addq $12, $21, $12 # U0 hi mul + carry | |
cmpult $6, $13, $20 # L0 lo add => carry | |
bis $31, $31, $31 # U1 mt | |
lda $16, 64($16) # L1 bookkeeping | |
addq $6, $12, $22 # U0 hi add => answer | |
bis $31, $31, $31 # U1 mt | |
cmpult $22, $12, $21 # L0 hi add => carry | |
addq $14, $20, $14 # U0 hi mul + carry | |
ldq $6, -16($16) # L1 | |
bis $31, $31, $31 # U1 mt | |
addq $7, $15, $23 # L0 lo + acc | |
addq $14, $21, $14 # U0 hi mul + carry | |
ldq $7, -8($16) # L1 | |
umulh $19, $1, $12 # U1 | |
cmpult $23, $15, $20 # L0 lo add => carry | |
addq $23, $14, $23 # U0 hi add => answer | |
ldq $0, 0($17) # L1 | |
mulq $19, $2, $13 # U1 | |
cmpult $23, $14, $21 # L0 hi add => carry | |
addq $8, $20, $8 # U0 hi mul + carry | |
ldq $1, 8($17) # L1 | |
umulh $19, $2, $14 # U1 | |
addq $4, $9, $4 # L0 lo + acc | |
stq $22, -48($16) # L0 | |
stq $23, -40($16) # L1 | |
bis $31, $31, $31 # L0 st slosh | |
mulq $19, $3, $15 # U1 | |
bis $31, $31, $31 # L1 st slosh | |
addq $8, $21, $8 # U0 hi mul + carry | |
cmpult $4, $9, $20 # L0 lo add => carry | |
addq $4, $8, $22 # U0 hi add => answer | |
bis $31, $31, $31 # L1 mt | |
bgt $18, $Loop # U1 bookkeeping | |
# ____ UNROLLED LOOP SOFTWARE PIPELINE FINISH ____ | |
$Lend: | |
cmpult $22, $8, $21 # L0 hi add => carry | |
addq $10, $20, $10 # U0 hi mul + carry | |
ldq $4, 0($16) # L1 | |
addq $5, $11, $23 # L0 lo + acc | |
addq $10, $21, $10 # L0 hi mul + carry | |
ldq $5, 8($16) # L1 | |
umulh $19, $3, $8 # U1 | |
cmpult $23, $11, $20 # L0 lo add => carry | |
addq $23, $10, $23 # U0 hi add => answer | |
mulq $19, $0, $9 # U1 | |
cmpult $23, $10, $21 # L0 hi add => carry | |
addq $12, $20, $12 # U0 hi mul + carry | |
umulh $19, $0, $10 # U1 | |
addq $6, $13, $6 # L0 lo + acc | |
stq $22, -32($16) # L0 | |
stq $23, -24($16) # L1 | |
mulq $19, $1, $11 # U1 | |
addq $12, $21, $12 # U0 hi mul + carry | |
cmpult $6, $13, $20 # L0 lo add => carry | |
addq $6, $12, $22 # U0 hi add => answer | |
cmpult $22, $12, $21 # L0 hi add => carry | |
addq $14, $20, $14 # U0 hi mul + carry | |
addq $7, $15, $23 # L0 lo + acc | |
addq $14, $21, $14 # U0 hi mul + carry | |
umulh $19, $1, $12 # U1 | |
cmpult $23, $15, $20 # L0 lo add => carry | |
addq $23, $14, $23 # U0 hi add => answer | |
cmpult $23, $14, $21 # L0 hi add => carry | |
addq $8, $20, $8 # U0 hi mul + carry | |
addq $4, $9, $4 # U0 lo + acc | |
stq $22, -16($16) # L0 | |
stq $23, -8($16) # L1 | |
bis $31, $31, $31 # L0 st slosh | |
addq $8, $21, $8 # L0 hi mul + carry | |
cmpult $4, $9, $20 # L0 lo add => carry | |
addq $4, $8, $22 # U0 hi add => answer | |
cmpult $22, $8, $21 # L0 hi add => carry | |
addq $10, $20, $10 # U0 hi mul + carry | |
addq $5, $11, $23 # L0 lo + acc | |
addq $10, $21, $10 # L0 hi mul + carry | |
cmpult $23, $11, $20 # L0 lo add => carry | |
addq $23, $10, $23 # U0 hi add => answer | |
cmpult $23, $10, $21 # L0 hi add => carry | |
addq $12, $20, $12 # U0 hi mul + carry | |
stq $22, 0($16) # L0 | |
stq $23, 8($16) # L1 | |
addq $12, $21, $0 # U0 hi mul + carry | |
ldq $9, 8($30) | |
ldq $10, 16($30) | |
ldq $11, 24($30) | |
ldq $12, 32($30) | |
ldq $13, 40($30) | |
ldq $14, 48($30) | |
ldq $15, 56($30) | |
lda $30, 240($30) | |
ret $31, ($26), 1 | |
.end __mpn_addmul_1 |