Update README for evp_hash -o options

Author: andrewkdinh

README.md

@@ -200,19 +200,22 @@ The test program supports options as follows:
 
 Tool that computes hashes using the specified algorithm.
 Runs for 5 seconds and prints the average execution time per hash.
-Uses the EVP API by default, but this tool can also use the corresponding deprecated API's.
 Prints out the average time per hash computation.
+Three modes of operation:
+- deprecated: Use deprecated, legacy API's to do hash (e.g. SHA1_Init)
+- evp_isolated: Use EVP API and don't allow shared data between threads
+- evp_shared (default): Use EVP API and allow shared data between threads
 
 ```
-Usage: evp_hash [-h] [-x] [-t] [-u update-times] [-a algorithm] thread-count
+Usage: evp_hash [-h] [-t] [-o operation] [-u update-times] [-a algorithm] thread-count
 -h - print this help output
--x - use deprecated API instead of EVP API
 -t - terse output
+-o operation - mode of operation. One of [deprecated, evp_isolated, evp_shared] (default: evp_shared)
 -u update-times - times to update digest. 1 for one-shot (default: 1)
 -a algorithm - One of: [SHA1, SHA224, SHA256, SHA384, SHA512] (default: SHA1)
 thread-count - number of threads
 ```
 
 ```sh
-evp_hash -u 10 -a SHA512 -x 15
+evp_hash -u 10 -a SHA512 -o evp_isolated 15
 ```