add endian.h for endian dependent stuff

1 files changed, 133 insertions, 0 deletions

diff --git a/endian.h b/endian.h
new file mode 100644
index 0000000..8448c79
--- /dev/null
+++ b/endian.h
@@ -0,0 +1,133 @@
+#ifndef ENDIAN_H_
+#define ENDIAN_H_
+
+#include "common.h"
+
+/*** Macros and functions for endian specific memory access ***/
+
+/** byte-swapping functions **/
+
+#if HAS_BUILTIN(bswap16)
+#define bswap16 __builtin_bswap16
+#else
+static inline ushort
+bswap16(ushort x) {
+   return x >> 8 | x << 8;
+}
+#endif
+
+#if HAS_BUILTIN(bswap32)
+#define bswap32 __builtin_bswap32
+#else
+static inline uint
+bswap32(uint x) {
+   return x >> 24 & 0x000000FF | x >>  8 & 0x0000FF00
+        | x <<  8 & 0x00FF0000 | x << 24 & 0xFF000000;
+}
+#endif
+
+#if HAS_BUILTIN(bswap64)
+#define bswap64 __builtin_bswap64
+#else
+static inline uvlong
+bswap64(uvlong x) {
+   return (uvlong) bswap32(x) << 32 | bswap32(x >> 32);
+}
+#endif
+
+#if (defined __BYTE_ORDER__ && __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__) ||               \
+    defined __hppa__ || defined __m68k__ || defined mc68000 || defined _M_M68K ||       \
+    (defined __MIPS__ && defined __MIPSEB__) ||                                         \
+    defined __ppc__ || defined __POWERPC__ || defined __powerpc__ || defined __PPC__ || \
+    defined __sparc__
+#define HOST_BIG_ENDIAN
+#define hostntarg_sameendian() (targ_bigendian)
+#else
+#define HOST_LIL_ENDIAN
+#define hostntarg_sameendian() (!targ_bigendian)
+#endif
+
+/** little-endian memory writes **/
+
+static inline void
+wr16le(uchar *p, ushort x)
+{
+#ifndef HOST_LIL_ENDIAN
+   x = bswap16(x);
+#endif
+   memcpy(p, &x, sizeof x);
+}
+
+static inline void
+wr32le(uchar *p, uint x)
+{
+#ifndef HOST_LIL_ENDIAN
+   x = bswap32(x);
+#endif
+   memcpy(p, &x, sizeof x);
+}
+
+static inline void
+wr64le(uchar *p, uvlong x)
+{
+#ifndef HOST_LIL_ENDIAN
+   x = bswap64(x);
+#endif
+   memcpy(p, &x, sizeof x);
+}
+
+/** big-endian memory writes **/
+
+static inline void
+wr16be(uchar *p, ushort x)
+{
+#ifndef HOST_BIG_ENDIAN
+   x = bswap16(x);
+#endif
+   memcpy(p, &x, sizeof x);
+}
+
+static inline void
+wr32be(uchar *p, uint x)
+{
+#ifndef HOST_BIG_ENDIAN
+   x = bswap32(x);
+#endif
+   memcpy(p, &x, sizeof x);
+}
+
+static inline void
+wr64be(uchar *p, uvlong x)
+{
+#ifndef HOST_BIG_ENDIAN
+   x = bswap64(x);
+#endif
+   memcpy(p, &x, sizeof x);
+}
+
+/** target-endian memory writes **/
+
+static inline void
+wr16targ(uchar *p, ushort x)
+{
+   if (!hostntarg_sameendian()) x = bswap16(x);
+   memcpy(p, &x, sizeof x);
+}
+
+static inline void
+wr32targ(uchar *p, uint x)
+{
+   if (!hostntarg_sameendian()) x = bswap32(x);
+   memcpy(p, &x, sizeof x);
+}
+
+static inline void
+wr64targ(uchar *p, uvlong x)
+{
+   if (!hostntarg_sameendian()) x = bswap64(x);
+   memcpy(p, &x, sizeof x);
+}
+
+#endif /* ENDIAN_H_ */
+
+/* vim:set ts=3 sw=3 expandtab: */