fbsim

commit 5d39da4638130a3168d79bb4f76f8d877e3c1674
parent 4e67c25846e9bbe88b960d236fcc2f798fae7b66
Author: Morel Bérenger <berengermorel76@gmail.com>
Date:   Fri, 18 Sep 2020 15:39:33 +0200

simplified the likely to be taken path

Diffstat:
M
src/main.c
 | 
33
++++++++++++++++++++++++---------

1 file changed, 24 insertions(+), 9 deletions(-)
diff --git a/src/main.c b/src/main.c
@@ -216,14 +216,34 @@ int main(int argc, char *argv[])
 
 	fprintf( stdout, "updates screen every %zu nano seconds (10^-9)\n", timer.tv_nsec );
 
-	while( -1 != nanosleep( &timer, NULL ) )
+	//unlikely case
+	if( SDL_MUSTLOCK( screen ) )
 	{
-		if( SDL_MUSTLOCK( screen ) && -1 == SDL_LockSurface( screen ) )
+		fprintf( stdout, "using locks\n" );
+		while( -1 != nanosleep( &timer, NULL ) )
 		{
-			fprintf( stderr, "lock screen: %s.\n", SDL_GetError() );
-			exit( EXIT_FAILURE );
+			if( -1 == SDL_LockSurface( screen ) )
+			{
+				fprintf( stderr, "lock screen: %s.\n", SDL_GetError() );
+				exit( EXIT_FAILURE );
+			}
+
+			uint8_t const* srcy = fbsim.mem;
+			uint8_t * dsty = screen->pixels;
+			for( ; srcy < endsrcy; srcy += srcw, dsty += scanline )
+			{
+				memcpy( dsty, srcy, srcw );
+			}
+
+			SDL_UnlockSurface( screen );
+			SDL_Flip( screen );
 		}
+		exit( EXIT_SUCCESS );
+	}
 
+	//most likely case
+	while( -1 != nanosleep( &timer, NULL ) )
+	{
 		uint8_t const* srcy = fbsim.mem;
 		uint8_t * dsty = screen->pixels;
 		for( ; srcy < endsrcy; srcy += srcw, dsty += scanline )
@@ -231,11 +251,6 @@ int main(int argc, char *argv[])
 			memcpy( dsty, srcy, srcw );
 		}
 
-		if( SDL_MUSTLOCK( screen ) )
-		{
-			SDL_UnlockSurface( screen );
-		}
-
 		SDL_Flip( screen );
 	}
 	exit( EXIT_SUCCESS );