Write functions to handle loading and saving words a block at a time, taking into

account endian differences.

The current code does not take advantage of the knowledge of which endianness
we are running on; an optimization suggested by Yves Jerschow is to use (unsafe)
casts to speed up the load/store operations. This turns out to provide large
performance increases (30% or more) in some cases.

Even without the unsafe casts, this version seems to average a few percent
faster, probably because the longer loading loops have been partially or
fully unrolled.

This also makes the code implementing low-level algorithms like ciphers and
hashes a bit more succint.

1 files changed, 1 insertions, 3 deletions

diff --git a/src/prf_x942.cpp b/src/prf_x942.cpp
index 6e67aab8b..fd29aecdd 100644
--- a/src/prf_x942.cpp
+++ b/src/prf_x942.cpp
@@ -21,9 +21,7 @@ namespace {
 MemoryVector<byte> encode_x942_int(u32bit n)
    {
    byte n_buf[4] = { 0 };
-   for(u32bit j = 0; j != 4; ++j)
-      n_buf[j] = get_byte(j, n);
-
+   store_be(n, n_buf);
    return DER_Encoder().encode(n_buf, 4, OCTET_STRING).get_contents();
    }