diff --git a/libffi/src/x86/ffi.c b/libffi/src/x86/ffi.c
index 886a2e0e..243a406a 100644
--- a/libffi/src/x86/ffi.c
+++ b/libffi/src/x86/ffi.c
@@ -325,7 +325,7 @@ ffi_prep_incoming_args_SYSV(char *stack, void **rvalue, void **avalue,
 ({ unsigned char *__tramp = (unsigned char*)(TRAMP); \
    unsigned int  __fun = (unsigned int)(FUN); \
    unsigned int  __ctx = (unsigned int)(CTX); \
-   unsigned int  __dis = __fun - ((unsigned int) __tramp + 10); \
+   unsigned int  __dis = __fun - (__ctx + 10); \
    unsigned short __size = (unsigned short)(SIZE); \
    *(unsigned char*) &__tramp[0] = 0xb8; \
    *(unsigned int*)  &__tramp[1] = __ctx; /* movl __ctx, %eax */ \