Re: [Qemu-devel] [PATCH] bswap: Don't rely on HOST_LONG_BITS

[Stefan Weil]

Am 30.01.2013 21:55, schrieb Richard Henderson:

This is not always defined in all places qemu/bswap.h is used.
If we include qemu-common.h to get it, we create an include loop.
This resolves a build problem on any big-endian host like ppc64.

Signed-off-by: Richard Henderson<r...@twiddle.net>
---
  include/qemu/bswap.h | 12 ++++++++++--
  1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/include/qemu/bswap.h b/include/qemu/bswap.h
index e6d4798..d3af35d 100644
--- a/include/qemu/bswap.h
+++ b/include/qemu/bswap.h
@@ -2,8 +2,8 @@
  #define BSWAP_H

  #include "config-host.h"
-
  #include<inttypes.h>
+#include<limits.h>
  #include "fpu/softfloat.h"

  #ifdef CONFIG_MACHINE_BSWAP_H
@@ -458,7 +458,15 @@ static inline void cpu_to_32wu(uint32_t *p, uint32_t v)

  static inline unsigned long leul_to_cpu(unsigned long v)
  {
-    return le_bswap(v, HOST_LONG_BITS);
+    /* In order to break an include loop between here and
+       qemu-common.h, don't rely on HOST_LONG_BITS.  */
+#if ULONG_MAX == UINT32_MAX
+    return le_bswap(v, 32);
+#elif ULONG_MAX == UINT64_MAX
+    return le_bswap(v, 64);
+#else
+# error Unknown sizeof long
+#endif
  }

  #undef le_bswap

That would be wrong for 64 bit MinGW-w64 because
HOST_LONG_BITS is _not_ the bit size of a long value.

See qemu-common.h for the correct definition.

Regards
Stefan W.