From: Martin Schwenke <martin@meltin.net>
Date: Wed, 16 Jun 2021 06:54:26 +0000 (+1000)
Subject: bn: save/restore registers to/from stack
X-Git-Tag: openssl-3.0.0-beta2~248
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3f55ff6af5dde97c6cda53bd735606f21b5707a5;p=thirdparty%2Fopenssl.git

bn: save/restore registers to/from stack

mtvsrd/mfvsrd are ISA >= 2.07 only, so this won't work for older
CPUs.

It would be possible to use this scheme only in the ISA >= 3.0
implementation.  However, in the future it may be possible for newer
ISAs to allow CPU implementations without a vector unit, so don't
bother.  The performance improvement versus using the stack was small
anyway.

Signed-off-by: Martin Schwenke <martin@meltin.net>
Reviewed-by: Amitay Isaacs <amitay@gmail.com>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Paul Dale <pauli@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/15798)
---

diff --git a/crypto/bn/asm/ppc64-mont-fixed.pl b/crypto/bn/asm/ppc64-mont-fixed.pl
index bb4290182db..da4967a730f 100755
--- a/crypto/bn/asm/ppc64-mont-fixed.pl
+++ b/crypto/bn/asm/ppc64-mont-fixed.pl
@@ -345,12 +345,12 @@ sub save_registers($)
 	my $n = $self->{n};
 
 	$self->add_code(<<___);
-	mtvsrd	$vsrs[0],$lo
+	std	$lo,-8($sp)
 ___
 
 	for (my $j = 0; $j <= $n+1; $j++) {
 		$self->{code}.=<<___;
-	mtvsrd	$vsrs[$j+1],$tp[$j]
+	std	$tp[$j],-`($j+2)*8`($sp)
 ___
 	}
 
@@ -366,12 +366,12 @@ sub restore_registers($)
 	my $n = $self->{n};
 
 	$self->add_code(<<___);
-	mfvsrd	$lo,$vsrs[0]
+	ld	$lo,-8($sp)
 ___
 
 	for (my $j = 0; $j <= $n+1; $j++) {
 		$self->{code}.=<<___;
-	mfvsrd	$tp[$j],$vsrs[$j+1]
+	ld	$tp[$j],-`($j+2)*8`($sp)
 ___
 	}