bwap: add qemu_bswap helper

add helper that can swap values of 4, 2, 1 bytes

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/bswap.h b/bswap.h
index 45587042907ed4bc7160474a121d11210c979e67..aace9b76e963cddf9c4224e82d7e4caa31b48c45 100644 (file)
--- a/bswap.h
+++ b/bswap.h
@@ -214,4 +214,10 @@ static inline void cpu_to_be32wu(uint32_t *p, uint32_t v)
 #undef le_bswaps
 #undef be_bswaps
 
+/* len must be one of 1, 2, 4 */
+static inline uint32_t qemu_bswap_len(uint32_t value, int len)
+{
+    return bswap32(value) >> (32 - 8 * len);
+}
+
 #endif /* BSWAP_H */