From: Amitay Isaacs <amitay@ozlabs.org>
Date: Mon, 1 Feb 2021 05:20:12 +0000 (+1100)
Subject: Add a constant time zero check function for 64-bit integers
X-Git-Tag: openssl-3.0.0-alpha14~10
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=ceaa6b319e01bd1ac74e3e7c5662745d3d3b3b9d;p=thirdparty%2Fopenssl.git

Add a constant time zero check function for 64-bit integers

Signed-off-by: Amitay Isaacs <amitay@ozlabs.org>

Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/14784)
---

diff --git a/include/internal/constant_time.h b/include/internal/constant_time.h
index cb4ce80830f..0ed6f823c11 100644
--- a/include/internal/constant_time.h
+++ b/include/internal/constant_time.h
@@ -182,6 +182,11 @@ static ossl_inline uint32_t constant_time_is_zero_32(uint32_t a)
     return constant_time_msb_32(~a & (a - 1));
 }
 
+static ossl_inline uint64_t constant_time_is_zero_64(uint64_t a)
+{
+    return constant_time_msb_64(~a & (a - 1));
+}
+
 static ossl_inline unsigned int constant_time_eq(unsigned int a,
                                                  unsigned int b)
 {