# module performance by implementing dedicated squaring code-path and
# possibly by unrolling loops...
+# January 2009.
+#
+# Reschedule to minimize/avoid Address Generation Interlock hazard,
+# make inner loops counter-based.
+
$mn0="%r0";
$num="%r1";
$nlo="%r11";
$AHI="%r12";
$NHI="%r13";
-$fp="%r14";
+$count="%r14";
$sp="%r15";
$code.=<<___;
bn_mul_mont:
lgf $num,164($sp) # pull $num
sla $num,3 # $num to enumerate bytes
- la $rp,0($num,$rp) # pointers to point at the vectors' ends
- la $ap,0($num,$ap)
la $bp,0($num,$bp)
- la $np,0($num,$np)
- stmg %r2,%r15,16($sp)
+ stg %r2,16($sp)
cghi $num,16 #
lghi %r2,0 #
blr %r14 # if($num<16) return 0;
+ cghi $num,128 #
+ bhr %r14 # if($num>128) return 0;
- lcgr $num,$num # -$num
+ stmg %r3,%r15,24($sp)
+
+ lghi $rp,-160-8 # leave room for carry bit
+ lcgr $j,$num # -$num
lgr %r0,$sp
- lgr $fp,$sp
- aghi $fp,-160-8 # leave room for carry bit
- la $sp,0($num,$fp) # alloca
- stg %r0,0($sp)
- aghi $fp,160-8 # $fp to point at tp[$num-1]
+ la $rp,0($rp,$sp)
+ la $sp,0($j,$rp) # alloca
+ stg %r0,0($sp) # back chain
- la $bp,0($num,$bp) # restore $bp
+ sra $num,3 # restore $num
+ la $bp,0($j,$bp) # restore $bp
+ ahi $num,-1 # adjust $num for inner loop
lg $n0,0($n0) # pull n0
lg $bi,0($bp)
- lg $alo,0($num,$ap)
+ lg $alo,0($ap)
mlgr $ahi,$bi # ap[0]*bp[0]
lgr $AHI,$ahi
lgr $mn0,$alo # "tp[0]"*n0
msgr $mn0,$n0
- lg $nlo,0($num,$np)#
+ lg $nlo,0($np) #
mlgr $nhi,$mn0 # np[0]*m1
algr $nlo,$alo # +="tp[0]"
lghi $NHI,0
alcgr $NHI,$nhi
- lgr $j,$num
- aghi $j,8 # j=1
+ la $j,8(%r0) # j=1
+ lr $count,$num
+
+.align 16
.L1st:
lg $alo,0($j,$ap)
mlgr $ahi,$bi # ap[j]*bp[0]
algr $nlo,$alo
alcgr $NHI,$nhi
- stg $nlo,0($j,$fp) # tp[j-1]=
- aghi $j,8 # j++
- jnz .L1st
+ stg $nlo,160-8($j,$sp) # tp[j-1]=
+ la $j,8($j) # j++
+ brct $count,.L1st
algr $NHI,$AHI
lghi $AHI,0
alcgr $AHI,$AHI # upmost overflow bit
- stg $NHI,0($fp)
- stg $AHI,8($fp)
+ stg $NHI,160-8($j,$sp)
+ stg $AHI,160($j,$sp)
la $bp,8($bp) # bp++
.Louter:
lg $bi,0($bp) # bp[i]
- lg $alo,0($num,$ap)
+ lg $alo,0($ap)
mlgr $ahi,$bi # ap[0]*bp[i]
- alg $alo,8($num,$fp)# +=tp[0]
+ alg $alo,160($sp) # +=tp[0]
lghi $AHI,0
alcgr $AHI,$ahi
lgr $mn0,$alo
- msgr $mn0,$n0 # tp[0]*n0
+ msgr $mn0,$n0 # tp[0]*n0
- lg $nlo,0($num,$np)# np[0]
+ lg $nlo,0($np) # np[0]
mlgr $nhi,$mn0 # np[0]*m1
algr $nlo,$alo # +="tp[0]"
lghi $NHI,0
alcgr $NHI,$nhi
- lgr $j,$num
- aghi $j,8 # j=1
+ la $j,8(%r0) # j=1
+ lr $count,$num
+
+.align 16
.Linner:
lg $alo,0($j,$ap)
mlgr $ahi,$bi # ap[j]*bp[i]
algr $alo,$AHI
lghi $AHI,0
alcgr $ahi,$AHI
- alg $alo,8($j,$fp) # +=tp[j]
+ alg $alo,160($j,$sp)# +=tp[j]
alcgr $AHI,$ahi
lg $nlo,0($j,$np)
algr $nlo,$alo # +="tp[j]"
alcgr $NHI,$nhi
- stg $nlo,0($j,$fp) # tp[j-1]=
- aghi $j,8 # j++
- jnz .Linner
+ stg $nlo,160-8($j,$sp) # tp[j-1]=
+ la $j,8($j) # j++
+ brct $count,.Linner
algr $NHI,$AHI
lghi $AHI,0
alcgr $AHI,$AHI
- alg $NHI,8($fp) # accumulate previous upmost overflow bit
+ alg $NHI,160($j,$sp)# accumulate previous upmost overflow bit
lghi $ahi,0
alcgr $AHI,$ahi # new upmost overflow bit
- stg $NHI,0($fp)
- stg $AHI,8($fp)
+ stg $NHI,160-8($j,$sp)
+ stg $AHI,160($j,$sp)
la $bp,8($bp) # bp++
- clg $bp,16+32($fp) # compare to &bp[num]
+ clg $bp,160+8+32($j,$sp) # compare to &bp[num]
jne .Louter
-___
-undef $bi;
-$count=$ap; undef $ap;
-
-$code.=<<___;
- lg $rp,16+16($fp) # reincarnate rp
- lgr $j,$num
- ltgr $AHI,$AHI
- jnz .Lsub # upmost overflow bit is not zero
- #slg $NHI,-8($np) # tp[num-1]-np[num-1]
- lghi $count,-8 # buggy assembler
- slg $NHI,0($count,$np) # buggy assembler
- jnle .Lsub # branch if not borrow
-
-.Lcopy: lg $alo,8($j,$fp)
- stg $j,8($j,$fp)
- stg $alo,0($j,$rp)
- aghi $j,8
- jnz .Lcopy
-.Lexit:
- lmg %r6,%r15,16+48($fp)
- lghi %r2,1 # signal "processed"
- br %r14
+ lg $rp,160+8+16($j,$sp) # reincarnate rp
+ la $ap,160($sp)
+ ahi $num,1 # restore $num, incidentally clears "borrow"
-.Lsub: lcgr $count,$num
- sra $count,3 # incidentally clears "borrow"
-.Lsubloop:
- lg $alo,8($j,$fp)
+ la $j,0(%r0)
+ lr $count,$num
+.Lsub: lg $alo,0($j,$ap)
slbg $alo,0($j,$np)
stg $alo,0($j,$rp)
la $j,8($j)
- brct $count,.Lsubloop
+ brct $count,.Lsub
lghi $ahi,0
- slbgr $AHI,$ahi
- lgr $j,$num
- jle .Lcopy # branch if borrow
-
-.Lzap: stg $j,8($j,$fp)
- aghi $j,8
- jnz .Lzap
- j .Lexit
+ slbgr $AHI,$ahi # handle upmost carry
+
+ ngr $ap,$AHI
+ lghi $np,-1
+ xgr $np,$AHI
+ ngr $np,$rp
+ ogr $ap,$np # ap=borrow?tp:rp
+
+ la $j,0(%r0)
+ lgr $count,$num
+.Lcopy: lg $alo,0($j,$ap) # copy or in-place refresh
+ stg $j,160($j,$sp) # zap tp
+ stg $alo,0($j,$rp)
+ la $j,8($j)
+ brct $count,.Lcopy
+
+ la %r1,160+8+48($j,$sp)
+ lmg %r6,%r15,0(%r1)
+ lghi %r2,1 # signal "processed"
+ br %r14
.size bn_mul_mont,.-bn_mul_mont
.string "Montgomery Multiplication for s390x, CRYPTOGAMS by <appro\@openssl.org>"
___