Use inline-asm only with gcc. Add fallback for other compilers

git-svn-id: svn://mattst88.com/svn/glpong3d/trunk@19 4dd1920e-271a-0410-bca0-81b404a81564

1 files changed, 12 insertions, 7 deletions

diff --git a/glpong3d.c b/glpong3d.c
index a02a17f..c4739a8 100644
--- a/glpong3d.c
+++ b/glpong3d.c
@@ -451,18 +451,23 @@ void GLPong_CleanUp() {
 
 }
 
-__inline__ unsigned int NextPow2(unsigned int value) {   
+static __inline__ unsigned int
+NextPow2(unsigned int value) {   
+#if (defined __i386__ || defined __amd64__ || defined __x86_64__) \
+ && (defined __GNUC__)
 	unsigned int x;
-#ifdef __i386__
-	__asm("dec %1\n\t"
-		"movl $2,%0\n\t"
-		"bsr %1,%1\n\t"
-		"shl %b1,%0\n\t"
+	__asm(
+		"dec    %1      \n\t" /* so that if the number is a power of 
+                                       * two we don't change it
+                                       */
+		"movl   $2,%0   \n\t"
+		"bsr    %1,%1   \n\t"
+		"shl    %b1,%0  \n\t"
 		: "=r" (x)
 		: "c" (value)
 	);
 #else
-	x = 1;
+	unsigned int x = 0;
 	while (x < value) {
 		x *= 2;
 	}