diff --git a/headers/os/support/TLS.h b/headers/os/support/TLS.h
index 27503c1bb4..855897fedd 100644
--- a/headers/os/support/TLS.h
+++ b/headers/os/support/TLS.h
@@ -1,28 +1,40 @@
 #ifndef _TLS_H
-#define	_TLS_H	1
+#define	_TLS_H
+/* 
+** Distributed under the terms of the OpenBeOS License.
+*/
 
 #include <BeBuild.h>
 #include <SupportDefs.h>
 
+/* A maximum of 64 keys is allowed to store in TLS - the key is reserved
+ * process-wide. Note that tls_allocate() will return B_NO_MEMORY if you
+ * try to exceed this limit.
+ */
+#define TLS_MAX_KEYS	64
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
-extern _IMPEXP_ROOT int32	tls_allocate(void);
+extern int32 tls_allocate(void);
 
-#if __INTEL__
+#if !_NO_INLINE_ASM && __INTEL__ && __GNUC__
 
-static inline void * tls_get(int32 index) {
-	void	*ret;
+static inline void *
+tls_get(int32 index)
+{
+	void *ret;
 	__asm__ __volatile__ ( 
 		"movl	%%fs:(,%%edx, 4), %%eax \n\t"
 		: "=a"(ret) : "d"(index) );
 	return ret;
 }
 
-static inline void * tls_address(int32 index) {
-	void	*ret;
+static inline void **
+tls_address(int32 index)
+{
+	void *ret;
 	__asm__ __volatile__ ( 
 		"movl	%%fs:0, %%eax \n\t"
 		"leal	(%%eax, %%edx, 4), %%eax \n\t"
@@ -30,7 +42,9 @@ static inline void * tls_address(int32 index) {
 	return ret;
 }
 
-static inline void 	tls_set(int32 index, void *value) {
+static inline void
+tls_set(int32 index, void *value)
+{
 	__asm__ __volatile__ ( 
 		"movl	%%eax, %%fs:(,%%edx, 4) \n\t"
 		: : "d"(index), "a"(value) );
@@ -38,9 +52,9 @@ static inline void 	tls_set(int32 index, void *value) {
 
 #else
 
-extern _IMPEXP_ROOT void *	tls_get(int32 index);
-extern _IMPEXP_ROOT void **	tls_address(int32 index);
-extern _IMPEXP_ROOT void 	tls_set(int32 index, void *value);
+extern void *tls_get(int32 index);
+extern void **tls_address(int32 index);
+extern void tls_set(int32 index, void *value);
 
 #endif
 
@@ -48,4 +62,4 @@ extern _IMPEXP_ROOT void 	tls_set(int32 index, void *value);
 }
 #endif
 
-#endif
+#endif	/* _TLS_H */