Never set RC4_CHAR.

RC4_CHAR is a bit in the x86(-64) CPUID information that switches the
RC4 asm code from using an array of 256 uint32_t's to 256 uint8_t's. It
was originally written for the P4, where the uint8_t style was faster.

(On modern chips, setting RC4_CHAR took RC4-MD5 from 458 to 304 MB/s.
Although I wonder whether, on a server with many connections, using less
cache wouldn't be better.)

However, I'm not too worried about a slowdown of RC4 on P4 systems these
days (the last new P4 chip was released nine years ago) and I want the
code to be simplier.

Also, RC4_CHAR was set when the CPUID family was 15, but Intel actually
lists 15 as a special code meaning "also check the extended family
bits", which the asm didn't do.

The RC4_CHAR support remains in the RC4 asm code to avoid drift with
upstream.

Change-Id: If3febc925a83a76f453b9e9f8de5ee43759927c6
Reviewed-on: https://boringssl-review.googlesource.com/3550
Reviewed-by: David Benjamin <davidben@chromium.org>
Reviewed-by: Adam Langley <agl@google.com>

1 files changed, 0 insertions, 2 deletions

diff --git a/include/openssl/rc4.h b/include/openssl/rc4.h
index 727b4740..b5fc8ede 100644
--- a/include/openssl/rc4.h
+++ b/include/openssl/rc4.h
@@ -69,8 +69,6 @@ extern "C" {
 
 typedef struct rc4_key_st {
   uint32_t x, y;
-  /* data is sometimes used as an array of 32-bit values and sometimes as 8-bit
-   * values, depending on the platform. */
   uint32_t data[256];
 } RC4_KEY;