utils/bits.h: Support compiler magic for unaligned loads and stores.

[mLib] / utils / bits.h

diff --git a/utils/bits.h b/utils/bits.h
index 3b12f96..656eee5 100644 (file)
--- a/utils/bits.h
+++ b/utils/bits.h
@@ -40,6 +40,10 @@
 #  include <stdint.h>
 #endif
 
+#ifndef MLIB_COMPILER_H
+#  include "compiler.h"
+#endif
+
 /*----- Decide on some types ----------------------------------------------*/
 
 /* --- Make GNU C shut up --- */
@@ -316,6 +320,16 @@ typedef unsigned char octet, uint8;
 
 /* --- Endianness swapping --- */
 
+#if GCC_VERSION_P(4, 8)
+#  define ENDSWAP16(x) ((uint16)__builtin_bswap16(x))
+#endif
+#if GCC_VERSION_P(4, 3)
+#  define ENDSWAP32(x) ((uint32)__builtin_bswap32(x))
+#endif
+#if GCC_VERSION_P(4, 3) && defined(HAVE_UINT64)
+#  define ENDSWAP64(x) ((uint64)__builtin_bswap64(x))
+#endif
+
 #ifndef ENDSWAP8
 #  define ENDSWAP8(x) U8(x)
 #endif
@@ -411,8 +425,71 @@ typedef unsigned char octet, uint8;
 #  define BTOH64_(z, x) ASSIGN64(z, x)
 #endif
 
+/* --- Unaligned access (GCC-specific) --- */
+
+#if GCC_VERSION_P(3, 3) && CHAR_BIT == 8
+#  define MLIB_MISALIGNED __attribute__((aligned(1), may_alias))
+#  if __SIZEOF_SHORT__ == 2
+     typedef MLIB_MISALIGNED unsigned short misaligned_uint16;
+#    define RAW16(p) (*(misaligned_uint16 *)(p))
+#  endif
+#  if __SIZEOF_INT__ == 4
+     typedef MLIB_MISALIGNED unsigned int misaligned_uint32;
+#    define RAW32(p) (*(misaligned_uint32 *)(p))
+#  elif __SIZEOF_LONG__ == 4
+     typedef MLIB_MISALIGNED unsigned long misaligned_uint32;
+#    define RAW32(p) (*(misaligned_uint32 *)(p))
+#  endif
+#  if __SIZEOF_LONG__ == 8
+     typedef MLIB_MISALIGNED unsigned long misaligned_uint64;
+#    define RAW64(p) (*(misaligned_uint64 *)(p))
+#  elif __SIZEOF_LONG_LONG__ == 8
+     typedef MLIB_MISALIGNED unsigned long long misaligned_uint64;
+#    define RAW64(p) (*(misaligned_uint64 *)(p))
+#  endif
+#endif
+
 /* --- Storage and retrieval --- */
 
+#if defined(RAW16) && defined(LTOH16)
+#  define LOAD16_L(p) LTOH16(RAW16(p))
+#endif
+#if defined(RAW16) && defined(HTOL16)
+#  define STORE16_L(p, x) (RAW16(p) = HTOL16(x))
+#endif
+#if defined(RAW16) && defined(BTOH16)
+#  define LOAD16_B(p) BTOH16(RAW16(p))
+#endif
+#if defined(RAW16) && defined(HTOB16)
+#  define STORE16_B(p, x) (RAW16(p) = HTOB16(x))
+#endif
+
+#if defined(RAW32) && defined(LTOH32)
+#  define LOAD32_L(p) LTOH32(RAW32(p))
+#endif
+#if defined(RAW32) && defined(HTOL32)
+#  define STORE32_L(p, x) (RAW32(p) = HTOL32(x))
+#endif
+#if defined(RAW32) && defined(BTOH32)
+#  define LOAD32_B(p) BTOH32(RAW32(p))
+#endif
+#if defined(RAW32) && defined(HTOB32)
+#  define STORE32_B(p, x) (RAW32(p) = HTOB32(x))
+#endif
+
+#if defined(RAW64) && defined(LTOH64)
+#  define LOAD64_L(p) LTOH64(RAW64(p))
+#endif
+#if defined(RAW64) && defined(HTOL64)
+#  define STORE64_L(p, x) (RAW64(p) = HTOL64(x))
+#endif
+#if defined(RAW64) && defined(BTOH64)
+#  define LOAD64_B(p) BTOH64(RAW64(p))
+#endif
+#if defined(RAW64) && defined(HTOB64)
+#  define STORE64_B(p, x) (RAW64(p) = HTOB64(x))
+#endif
+
 #define GETBYTE(p, o) (((octet *)(p))[o] & MASK8)
 #define PUTBYTE(p, o, v) (((octet *)(p))[o] = U8((v)))