ffi: take advantage of hardware unaligned access.

* ffi.c (align_sw_get, align_sw_end, align_sw_put_end,
align_sw_put): On Intel, PowerPC and also on ARM if certain
compiler options are in effect (set by the user building TXR,
not us), define these macros to do nothing. This shrinks and
speeds up all the functions which use these macros for
handling unaligned accesses.

1 files changed, 11 insertions, 0 deletions

diff --git a/ffi.c b/ffi.c
index 53971cc4..2435bc8b 100644
--- a/ffi.c
+++ b/ffi.c
@@ -517,6 +517,15 @@ static void ffi_simple_release(struct txr_ffi_type *tft, val obj,
   *loc = 0;
 }
 
+#if __i386__ || __x86_64__ || __PPC64__ || __ARM_FEATURE_UNALIGNED
+
+#define align_sw_get(type, src)
+#define align_sw_end
+#define align_sw_put_end
+#define align_sw_put(type, dst, expr) (expr)
+
+#else
+
 #define align_sw_get(type, src)  {                                      \
   const int al = ((alignof (type) - 1) & coerce(uint_ptr_t, src)) == 0; \
   const size_t sz = sizeof (type);                                      \
@@ -543,6 +552,8 @@ static void ffi_simple_release(struct txr_ffi_type *tft, val obj,
   }                                                                     \
 }
 
+#endif
+
 #if HAVE_I8
 static void ffi_i8_put(struct txr_ffi_type *tft, val n, mem_t *dst, val self)
 {