Ensure that one can store X bytes in a fifo of size X.

[ffmpeg] / libavutil / bswap.h

diff --git a/libavutil/bswap.h b/libavutil/bswap.h
index a49e6e2c0af7d7b133a4c864c148c7a9afe4c9a0..b35fb5161334c63518235ab8153e6cafff533835 100644 (file)
--- a/libavutil/bswap.h
+++ b/libavutil/bswap.h
@@ -34,51 +34,41 @@
 #include <byteswap.h>
 #else
 
-#ifdef ARCH_X86_64
-#  define LEGACY_REGS "=Q"
-#else
-#  define LEGACY_REGS "=q"
-#endif
-
-static av_always_inline uint16_t bswap_16(uint16_t x)
+static av_always_inline av_const uint16_t bswap_16(uint16_t x)
 {
 #if defined(ARCH_X86)
-    __asm("rorw $8, %0"   :
-          LEGACY_REGS (x) :
-          "0" (x));
+    asm("rorw $8, %0" : "+r"(x));
 #elif defined(ARCH_SH4)
-    __asm__("swap.b %0,%0":"=r"(x):"0"(x));
+    asm("swap.b %0,%0" : "=r"(x) : "0"(x));
 #else
     x= (x>>8) | (x<<8);
 #endif
     return x;
 }
 
-static av_always_inline uint32_t bswap_32(uint32_t x)
+static av_always_inline av_const uint32_t bswap_32(uint32_t x)
 {
 #if defined(ARCH_X86)
 #ifdef HAVE_BSWAP
-    __asm("bswap   %0":
-          "=r" (x)    :
+    asm("bswap   %0" : "+r" (x));
 #else
-    __asm("xchgb   %b0,%h0\n"
-          "rorl    $16,%0 \n"
-          "xchgb   %b0,%h0":
-          LEGACY_REGS (x)  :
+    asm("rorw    $8,  %w0 \n\t"
+        "rorl    $16, %0  \n\t"
+        "rorw    $8,  %w0"
+        : "+r"(x));
 #endif
-          "0" (x));
 #elif defined(ARCH_SH4)
-    __asm__("swap.b %0,%0\n"
-            "swap.w %0,%0\n"
-            "swap.b %0,%0\n"
-            :"=r"(x):"0"(x));
+    asm("swap.b %0,%0\n"
+        "swap.w %0,%0\n"
+        "swap.b %0,%0\n"
+        : "=r"(x) : "0"(x));
 #elif defined(ARCH_ARM)
     uint32_t t;
-    __asm__ ("eor %1, %0, %0, ror #16 \n\t"
-             "bic %1, %1, #0xFF0000   \n\t"
-             "mov %0, %0, ror #8      \n\t"
-             "eor %0, %0, %1, lsr #8  \n\t"
-             : "+r"(x), "+r"(t));
+    asm ("eor %1, %0, %0, ror #16 \n\t"
+         "bic %1, %1, #0xFF0000   \n\t"
+         "mov %0, %0, ror #8      \n\t"
+         "eor %0, %0, %1, lsr #8  \n\t"
+         : "+r"(x), "+r"(t));
 #elif defined(ARCH_BFIN)
     unsigned tmp;
     asm("%1 = %0 >> 8 (V);      \n\t"
@@ -93,16 +83,14 @@ static av_always_inline uint32_t bswap_32(uint32_t x)
     return x;
 }
 
-static inline uint64_t bswap_64(uint64_t x)
+static inline uint64_t av_const bswap_64(uint64_t x)
 {
 #if 0
     x= ((x<< 8)&0xFF00FF00FF00FF00ULL) | ((x>> 8)&0x00FF00FF00FF00FFULL);
     x= ((x<<16)&0xFFFF0000FFFF0000ULL) | ((x>>16)&0x0000FFFF0000FFFFULL);
     return (x>>32) | (x<<32);
 #elif defined(ARCH_X86_64)
-  __asm("bswap  %0":
-        "=r" (x)   :
-        "0" (x));
+  asm("bswap  %0": "=r" (x) : "0" (x));
   return x;
 #else
     union {