ppccap.c: Split out algorithm-specific functions

Fixes #13336

Reviewed-by: Paul Dale <pauli@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/15828)

1 files changed, 51 insertions, 0 deletions

diff --git a/crypto/bn/bn_ppc.c b/crypto/bn/bn_ppc.c
new file mode 100644
index 0000000000..24b384acbd
--- /dev/null
+++ b/crypto/bn/bn_ppc.c
@@ -0,0 +1,51 @@
+/*
+ * Copyright 2009-2021 The OpenSSL Project Authors. All Rights Reserved.
+ *
+ * Licensed under the Apache License 2.0 (the "License").  You may not use
+ * this file except in compliance with the License.  You can obtain a copy
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
+ */
+
+#include <openssl/crypto.h>
+#include <openssl/bn.h>
+#include "crypto/ppc_arch.h"
+#include "bn_local.h"
+
+int bn_mul_mont(BN_ULONG *rp, const BN_ULONG *ap, const BN_ULONG *bp,
+                const BN_ULONG *np, const BN_ULONG *n0, int num)
+{
+    int bn_mul_mont_int(BN_ULONG *rp, const BN_ULONG *ap, const BN_ULONG *bp,
+                        const BN_ULONG *np, const BN_ULONG *n0, int num);
+    int bn_mul4x_mont_int(BN_ULONG *rp, const BN_ULONG *ap, const BN_ULONG *bp,
+                          const BN_ULONG *np, const BN_ULONG *n0, int num);
+    int bn_mul_mont_fixed_n6(BN_ULONG *rp, const BN_ULONG *ap,
+                             const BN_ULONG *bp, const BN_ULONG *np,
+                             const BN_ULONG *n0, int num);
+    int bn_mul_mont_300_fixed_n6(BN_ULONG *rp, const BN_ULONG *ap,
+                                 const BN_ULONG *bp, const BN_ULONG *np,
+                                 const BN_ULONG *n0, int num);
+
+    if (num < 4)
+        return 0;
+
+    if ((num & 3) == 0)
+        return bn_mul4x_mont_int(rp, ap, bp, np, n0, num);
+
+    /*
+     * There used to be [optional] call to bn_mul_mont_fpu64 here,
+     * but above subroutine is faster on contemporary processors.
+     * Formulation means that there might be old processors where
+     * FPU code path would be faster, POWER6 perhaps, but there was
+     * no opportunity to figure it out...
+     */
+
+    if (num == 6) {
+        if (OPENSSL_ppccap_P & PPC_MADD300)
+            return bn_mul_mont_300_fixed_n6(rp, ap, bp, np, n0, num);
+        else
+            return bn_mul_mont_fixed_n6(rp, ap, bp, np, n0, num);
+    }
+
+    return bn_mul_mont_int(rp, ap, bp, np, n0, num);
+}