Changeset 1959528 for libcfa/src/stdlib.hfa

Timestamp:

Jan 12, 2022, 6:34:58 PM (3 years ago)

Author:

Peter A. Buhr <pabuhr@…>

Branches:

ADT, ast-experimental, enum, forall-pointer-decay, master, pthread-emulation, qualifiedEnum

Children:

00f5fde

Parents:

a10f6b4

Message:

third attempt at specialized PRNG

File:

• libcfa/src/stdlib.hfa (modified) (4 diffs)

libcfa/src/stdlib.hfa

@@ -10 +10 @@
 // Created On       : Thu Jan 28 17:12:35 2016
 // Last Modified By : Peter A. Buhr
-// Last Modified On : Mon Jan 10 17:03:18 2022
-// Update Count     : 619
+// Last Modified On : Wed Jan 12 09:09:48 2022
+// Update Count     : 620
 //
 
@@ -386 +386 @@
 //---------------------------------------
 
+// Sequential Pseudo Random-Number Generator : generate repeatable sequence of values that appear random.
+//
+// Declaration :
+//   PRNG sprng = { 1009 } - set starting seed versus random seed
+//   
+// Interface :
+//   set_seed( sprng, 1009 ) - set starting seed for ALL kernel threads versus random seed
+//   get_seed( sprng ) - read seed
+//   prng( sprng ) - generate random value in range [0,UINT_MAX]
+//   prng( sprng, u ) - generate random value in range [0,u)
+//   prng( sprng, l, u ) - generate random value in range [l,u]
+//   calls( sprng ) - number of generated random value so far
+//
+// Examples : generate random number between 5-21
+//   prng( sprng ) % 17 + 5;    values 0-16 + 5 = 5-21
+//   prng( sprng, 16 + 1 ) + 5;
+//   prng( sprng, 5, 21 );
+//   calls( sprng );
+
 struct PRNG {
         uint32_t callcnt;                                                                       // call count
@@ -392 +411 @@
 }; // PRNG
 
+void set_seed( PRNG & prng, uint32_t seed_ );
 uint32_t prng( PRNG & prng ) __attribute__(( warn_unused_result )); // [0,UINT_MAX]
 static inline {
-        void set_seed( PRNG & prng, uint32_t seed_ ) with( prng ) { state = seed = seed_; } // set seed
         void ?{}( PRNG & prng ) { set_seed( prng, rdtscl() ); } // random seed
         void ?{}( PRNG & prng, uint32_t seed ) { set_seed( prng, seed ); } // fixed seed
@@ -403 +422 @@
 } // distribution
 
+// Concurrent Pseudo Random-Number Generator : generate repeatable sequence of values that appear random.
+//
+// Interface :
+//   set_seed( 1009 ) - fixed seed for all kernel threads versus random seed
+//   get_seed() - read seed
+//   prng() - generate random value in range [0,UINT_MAX]
+//   prng( u ) - generate random value in range [0,u)
+//   prng( l, u ) - generate random value in range [l,u]
+//
+// Examples : generate random number between 5-21
+//   prng() % 17 + 5;   values 0-16 + 5 = 5-21
+//   prng( 16 + 1 ) + 5;
+//   prng( 5, 21 );
+
 void set_seed( uint32_t seed_ ) OPTIONAL_THREAD;
-uint32_t get_seed() __attribute__(( warn_unused_result ));
+uint32_t get_seed() __attribute__(( warn_unused_result )) OPTIONAL_THREAD;
 uint32_t prng( void ) __attribute__(( warn_unused_result )) OPTIONAL_THREAD; // [0,UINT_MAX]
 static inline {