diff --git a/portable/ThirdParty/GCC/Posix/port.c b/portable/ThirdParty/GCC/Posix/port.c
index 8ec8193971b..24dd89f4539 100644
--- a/portable/ThirdParty/GCC/Posix/port.c
+++ b/portable/ThirdParty/GCC/Posix/port.c
@@ -148,10 +148,14 @@ StackType_t * pxPortInitialiseStack( StackType_t * pxTopOfStack,
      */
     thread = ( Thread_t * ) ( pxTopOfStack + 1 ) - 1;
     pxTopOfStack = ( StackType_t * ) thread - 1;
+
+    #ifdef __APPLE__
+        pxEndOfStack = ( StackType_t *) mach_vm_round_page( pxEndOfStack );
+    #endif
+
     ulStackSize = ( size_t ) ( pxTopOfStack + 1 - pxEndOfStack ) * sizeof( *pxTopOfStack );
 
     #ifdef __APPLE__
-        pxEndOfStack = mach_vm_round_page( pxEndOfStack );
         ulStackSize = mach_vm_trunc_page( ulStackSize );
     #endif