added prng functions

src/Makefile

@@ -3,7 +3,7 @@ DEFINES=
 
 CFLAGS=-m32 -O3 --std=c99 $(INCLUDES) $(DEFINES)
 
-OBJS=rl_backgrnd.o rl_image.o rl_map.o rl_sound.o rl_sprite.o rl_tile.o rl_version.o
+OBJS=rl_backgrnd.o rl_image.o rl_map.o rl_rand.o rl_sound.o rl_sprite.o rl_tile.o rl_version.o
 
 %.o: %.c
 	gcc $(CFLAGS) -c $< -o $@

src/rl_rand.c

@@ -0,0 +1,26 @@
+#include <rl_rand.h>
+
+static uint64_t seed;
+
+void rl_srand( uint64_t s )
+{
+  seed = s;
+}
+
+uint32_t rl_rand( void )
+{
+  /*
+  http://en.wikipedia.org/wiki/Linear_congruential_generator
+  Newlib parameters
+  */
+  
+  seed = 6364136223846793005ULL * seed + 1;
+  return seed >> 32;
+}
+
+int rl_random( int min, int max )
+{
+  /* fixed point math */
+  uint64_t dividend = max - min + 1;
+  return (int)( ( ( dividend * rl_rand() ) >> 32 ) + min );
+}

src/rl_rand.h

@@ -0,0 +1,10 @@
+#ifndef RL_RAND_H
+#define RL_RAND_H
+
+#include <stdint.h>
+
+void     rl_srand( uint64_t seed );
+uint32_t rl_rand( void );
+int      rl_random( int min, int max );
+
+#endif /* RL_RAND_H */

test/libretro/test.c

@@ -10,6 +10,7 @@
 #include <rl_sprite.h>
 #include <rl_sound.h>
 #include <rl_map.h>
+#include <rl_rand.h>
 #include <rl_version.h>
 
 #include <button_x.h>
@@ -186,7 +187,7 @@ static int testscr_init( testscr_t* s )
     goto error6;
   }
   
-  srand( perf_cb.get_time_usec() );
+  rl_srand( perf_cb.get_time_usec() );
   
   s->reset = 0;
   rl_sound_play_ogg( sketch008_ogg, sketch008_ogg_len, 1, NULL );
@@ -216,10 +217,10 @@ static void testscr_update( testscr_t* s )
     
     //s->reset = WIDTH * 6;
     s->count = 4;
-    // s->xx = rand() % WIDTH;
-    // s->yy = rand() % HEIGHT;
-    // s->dx = ( rand() & 1 ) * 2 - 1;
-    // s->dy = ( rand() & 1 ) * 2 - 1;
+    // s->xx = rl_random( 0, WIDTH - 1 );
+    // s->yy = rl_random( 0, HEIGHT - 1 );
+    // s->dx = ( rl_rand() & 1 ) * 2 - 1;
+    // s->dy = ( rl_rand() & 1 ) * 2 - 1;
     s->xx = 123.0f;
     s->yy = 73.0f;
     s->dx = 0.25f;
@@ -291,7 +292,7 @@ static void testscr_update( testscr_t* s )
       }
     }
     
-    fb[ ( height / 2 ) * pitch + width / 2 ] = ( rand() & 0x0f ) << 12 | ( rand() & 0x1f ) << 6 | ( rand() & 0x0f ) << 1;
+    fb[ ( height / 2 ) * pitch + width / 2 ] = ( rl_rand() & 0x0f ) << 12 | ( rl_rand() & 0x1f ) << 6 | ( rl_rand() & 0x0f ) << 1;
   }
   else
   {