ec/asm/ecp_nistz256-ppc64.pl: minor POWER8-specific optimization.

Up to 4% depending on benchmark.

Reviewed-by: Rich Salz <rsalz@openssl.org>

diff --git a/crypto/ec/asm/ecp_nistz256-ppc64.pl b/crypto/ec/asm/ecp_nistz256-ppc64.pl
index fadb9f78bab4935d03b4e6ec41dd7e6b9a088f4f..73d0746eb94acfdb1f80a133872e78ae0be1134e 100755 (executable)
--- a/crypto/ec/asm/ecp_nistz256-ppc64.pl
+++ b/crypto/ec/asm/ecp_nistz256-ppc64.pl
@@ -480,15 +480,15 @@ $code.=<<___;
        subfc   $t2,$t0,$acc0           # "*0xffff0001"
        subfe   $t3,$t1,$acc0
        addc    $acc0,$acc1,$t0         # +=acc[0]<<96 and omit acc[0]
-        mulld  $t0,$a0,$bi             # lo(a[0]*b[i])
        adde    $acc1,$acc2,$t1
-        mulld  $t1,$a1,$bi             # lo(a[1]*b[i])
        adde    $acc2,$acc3,$t2         # +=acc[0]*0xffff0001
-        mulld  $t2,$a2,$bi             # lo(a[2]*b[i])
        adde    $acc3,$acc4,$t3
-        mulld  $t3,$a3,$bi             # lo(a[3]*b[i])
        addze   $acc4,$acc5
 
+       mulld   $t0,$a0,$bi             # lo(a[0]*b[i])
+       mulld   $t1,$a1,$bi             # lo(a[1]*b[i])
+       mulld   $t2,$a2,$bi             # lo(a[2]*b[i])
+       mulld   $t3,$a3,$bi             # lo(a[3]*b[i])
        addc    $acc0,$acc0,$t0         # accumulate low parts of multiplication
         mulhdu $t0,$a0,$bi             # hi(a[0]*b[i])
        adde    $acc1,$acc1,$t1
@@ -508,8 +508,8 @@ $code.=<<___;
        adde    $acc2,$acc2,$t1
         srdi   $t1,$acc0,32
        adde    $acc3,$acc3,$t2
-        li     $acc5,0
        adde    $acc4,$acc4,$t3
+       li      $acc5,0
        addze   $acc5,$acc5
 ___
 }
@@ -587,38 +587,38 @@ __ecp_nistz256_sqr_mont:
        mulhdu  $acc6,$a3,$a2
 
        addc    $t1,$t1,$t2             # accumulate high parts of multiplication
-        mulld  $acc0,$a0,$a0           # a[0]*a[0]
        addze   $t2,$t3                 # can't overflow
 
        addc    $acc3,$acc3,$t0         # accumulate low parts of multiplication
-        mulhdu $a0,$a0,$a0
        adde    $acc4,$acc4,$t1
-        mulld  $t1,$a1,$a1             # a[1]*a[1]
        adde    $acc5,$acc5,$t2
-        mulhdu $a1,$a1,$a1
        addze   $acc6,$acc6             # can't overflow
 
        addc    $acc1,$acc1,$acc1       # acc[1-6]*=2
-        mulld  $t2,$a2,$a2             # a[2]*a[2]
        adde    $acc2,$acc2,$acc2
-        mulhdu $a2,$a2,$a2
        adde    $acc3,$acc3,$acc3
-        mulld  $t3,$a3,$a3             # a[3]*a[3]
        adde    $acc4,$acc4,$acc4
-        mulhdu $a3,$a3,$a3
        adde    $acc5,$acc5,$acc5
        adde    $acc6,$acc6,$acc6
        li      $acc7,0
        addze   $acc7,$acc7
 
+       mulld   $acc0,$a0,$a0           # a[0]*a[0]
+       mulhdu  $a0,$a0,$a0
+       mulld   $t1,$a1,$a1             # a[1]*a[1]
+       mulhdu  $a1,$a1,$a1
+       mulld   $t2,$a2,$a2             # a[2]*a[2]
+       mulhdu  $a2,$a2,$a2
+       mulld   $t3,$a3,$a3             # a[3]*a[3]
+       mulhdu  $a3,$a3,$a3
        addc    $acc1,$acc1,$a0         # +a[i]*a[i]
+        sldi   $t0,$acc0,32
        adde    $acc2,$acc2,$t1
+        srdi   $t1,$acc0,32
        adde    $acc3,$acc3,$a1
        adde    $acc4,$acc4,$t2
        adde    $acc5,$acc5,$a2
-        sldi   $t0,$acc0,32
        adde    $acc6,$acc6,$t3
-        srdi   $t1,$acc0,32
        adde    $acc7,$acc7,$a3
 ___
 for($i=0;$i<3;$i++) {                  # reductions, see commentary in
@@ -627,10 +627,10 @@ $code.=<<___;
        subfc   $t2,$t0,$acc0           # "*0xffff0001"
        subfe   $t3,$t1,$acc0
        addc    $acc0,$acc1,$t0         # +=acc[0]<<96 and omit acc[0]
-       adde    $acc1,$acc2,$t1
         sldi   $t0,$acc0,32
-       adde    $acc2,$acc3,$t2         # +=acc[0]*0xffff0001
+       adde    $acc1,$acc2,$t1
         srdi   $t1,$acc0,32
+       adde    $acc2,$acc3,$t2         # +=acc[0]*0xffff0001
        addze   $acc3,$t3               # can't overflow
 ___
 }
@@ -640,13 +640,13 @@ $code.=<<___;
        addc    $acc0,$acc1,$t0         # +=acc[0]<<96 and omit acc[0]
        adde    $acc1,$acc2,$t1
        adde    $acc2,$acc3,$t2         # +=acc[0]*0xffff0001
-       li      $t2,0
        addze   $acc3,$t3               # can't overflow
 
        addc    $acc0,$acc0,$acc4       # accumulate upper half
        adde    $acc1,$acc1,$acc5
        adde    $acc2,$acc2,$acc6
        adde    $acc3,$acc3,$acc7
+       li      $t2,0
        addze   $acc4,$t2
 
        addic   $acc0,$acc0,1           # ret -= modulus