bn/asm/sparcv9-mont.pl: fix squaring code path.

This module is used only with odd input lengths, i.e. not used in normal
PKI cases, on contemporary processors. The problem was "illuminated" by
fuzzing tests.
Reviewed-by: NRichard Levitte <levitte@openssl.org>

crypto/bn/asm/sparcv9-mont.pl

@@ -300,7 +300,7 @@ ___
 ######## .Lbn_sqr_mont gives up to 20% *overall* improvement over
 ######## code without following dedicated squaring procedure.
 ########
-$sbit="%i2";		# re-use $bp!
+$sbit="%o5";
 
 $code.=<<___;
 .align	32
@@ -413,7 +413,7 @@ $code.=<<___;
 	mulx	$apj,$mul0,$acc0
 	mulx	$npj,$mul1,$acc1
 	add	$acc0,$car0,$car0
-	add	$tpj,$car1,$car1
+	add	$tpj,$sbit,$sbit
 	ld	[$ap+$j],$apj			! ap[j]
 	and	$car0,$mask,$acc0
 	ld	[$np+$j],$npj			! np[j]
@@ -422,7 +422,7 @@ $code.=<<___;
 	ld	[$tp+8],$tpj			! tp[j]
 	add	$acc0,$acc0,$acc0
 	add	$j,4,$j				! j++
-	or	$sbit,$acc0,$acc0
+	add	$sbit,$acc0,$acc0
 	srlx	$acc0,32,$sbit
 	and	$acc0,$mask,$acc0
 	cmp	$j,$num
@@ -436,12 +436,12 @@ $code.=<<___;
 	mulx	$apj,$mul0,$acc0
 	mulx	$npj,$mul1,$acc1
 	add	$acc0,$car0,$car0
-	add	$tpj,$car1,$car1
+	add	$tpj,$sbit,$sbit
 	and	$car0,$mask,$acc0
 	srlx	$car0,32,$car0
 	add	$acc1,$car1,$car1
 	add	$acc0,$acc0,$acc0
-	or	$sbit,$acc0,$acc0
+	add	$sbit,$acc0,$acc0
 	srlx	$acc0,32,$sbit
 	and	$acc0,$mask,$acc0
 	add	$acc0,$car1,$car1
@@ -449,7 +449,7 @@ $code.=<<___;
 	srlx	$car1,32,$car1
 
 	add	$car0,$car0,$car0
-	or	$sbit,$car0,$car0
+	add	$sbit,$car0,$car0
 	add	$car0,$car1,$car1
 	add	$car2,$car1,$car1
 	st	$car1,[$tp+4]
@@ -509,7 +509,7 @@ $code.=<<___;
 .Lsqr_inner2:
 	mulx	$apj,$mul0,$acc0
 	mulx	$npj,$mul1,$acc1
-	add	$tpj,$car1,$car1
+	add	$tpj,$sbit,$sbit
 	add	$acc0,$car0,$car0
 	ld	[$ap+$j],$apj			! ap[j]
 	and	$car0,$mask,$acc0
@@ -517,7 +517,7 @@ $code.=<<___;
 	srlx	$car0,32,$car0
 	add	$acc0,$acc0,$acc0
 	ld	[$tp+8],$tpj			! tp[j]
-	or	$sbit,$acc0,$acc0
+	add	$sbit,$acc0,$acc0
 	add	$j,4,$j				! j++
 	srlx	$acc0,32,$sbit
 	and	$acc0,$mask,$acc0
@@ -532,12 +532,12 @@ $code.=<<___;
 .Lsqr_no_inner2:
 	mulx	$apj,$mul0,$acc0
 	mulx	$npj,$mul1,$acc1
-	add	$tpj,$car1,$car1
+	add	$tpj,$sbit,$sbit
 	add	$acc0,$car0,$car0
 	and	$car0,$mask,$acc0
 	srlx	$car0,32,$car0
 	add	$acc0,$acc0,$acc0
-	or	$sbit,$acc0,$acc0
+	add	$sbit,$acc0,$acc0
 	srlx	$acc0,32,$sbit
 	and	$acc0,$mask,$acc0
 	add	$acc0,$car1,$car1
@@ -546,7 +546,7 @@ $code.=<<___;
 	srlx	$car1,32,$car1
 
 	add	$car0,$car0,$car0
-	or	$sbit,$car0,$car0
+	add	$sbit,$car0,$car0
 	add	$car0,$car1,$car1
 	add	$car2,$car1,$car1
 	st	$car1,[$tp+4]
@@ -591,14 +591,17 @@ $code.=<<___;
 !.Lsqr_last
 
 	mulx	$npj,$mul1,$acc1
-	add	$tpj,$car1,$car1
+	add	$tpj,$acc0,$acc0
+	srlx	$acc0,32,$tmp0
+	and	$acc0,$mask,$acc0
+	add	$tmp0,$sbit,$sbit
 	add	$acc0,$car1,$car1
 	add	$acc1,$car1,$car1
 	st	$car1,[$tp]
 	srlx	$car1,32,$car1
 
 	add	$car0,$car0,$car0		! recover $car0
-	or	$sbit,$car0,$car0
+	add	$sbit,$car0,$car0
 	add	$car0,$car1,$car1
 	add	$car2,$car1,$car1
 	st	$car1,[$tp+4]