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authorAndy Polyakov <appro@openssl.org>2006-10-23 07:44:51 +0000
committerAndy Polyakov <appro@openssl.org>2006-10-23 07:44:51 +0000
commit544d8455858fad2cbc5d8637a31ceb34fcadaead (patch)
tree3d91e3abd44065986dec1bc9d7e95c187304ddfe /doc
parenta6efc2d1b8848e3a9f57acfea881e187afa38820 (diff)
OPENSSL_ia32cap.pod update.
Diffstat (limited to 'doc')
-rw-r--r--doc/crypto/OPENSSL_ia32cap.pod13
1 files changed, 7 insertions, 6 deletions
diff --git a/doc/crypto/OPENSSL_ia32cap.pod b/doc/crypto/OPENSSL_ia32cap.pod
index 121a8ddee5..03ac6e6834 100644
--- a/doc/crypto/OPENSSL_ia32cap.pod
+++ b/doc/crypto/OPENSSL_ia32cap.pod
@@ -17,18 +17,19 @@ register after executing CPUID instruction with EAX=1 input value (see
Intel Application Note #241618). Naturally it's meaningful on IA-32[E]
platforms only. The variable is normally set up automatically upon
toolkit initialization, but can be manipulated afterwards to modify
-crypto library behaviour. For the moment of this writing three bits are
+crypto library behaviour. For the moment of this writing five bits are
significant, namely bit #28 denoting Hyperthreading, which is used to
-distinguish Intel P4 core, bit #26 denoting SSE2 support, and bit #4
-denoting presence of Time-Stamp Counter. Clearing bit #26 at run-time
-for example disables high-performance SSE2 code present in the crypto
+distinguish Intel P4 core, bit #26 denoting SSE2 support, bit #25
+denoting SSE support, bit #23 denoting MMX support, and bit #4 denoting
+presence of Time-Stamp Counter. Clearing bit #26 at run-time for
+example disables high-performance SSE2 code present in the crypto
library. You might have to do this if target OpenSSL application is
executed on SSE2 capable CPU, but under control of OS which does not
support SSE2 extentions. Even though you can manipulate the value
programmatically, you most likely will find it more appropriate to set
up an environment variable with the same name prior starting target
-application, e.g. 'env OPENSSL_ia32cap=0x10 apps/openssl', to achieve
-same effect without modifying the application source code.
+application, e.g. 'env OPENSSL_ia32cap=0x12800010 apps/openssl', to
+achieve same effect without modifying the application source code.
Alternatively you can reconfigure the toolkit with no-sse2 option and
recompile.