Merge remote-tracking branch 'qatar/master'

[ffmpeg] / libavcodec / mathops.h

diff --git a/libavcodec/mathops.h b/libavcodec/mathops.h
index 2840735c793e845bc467ce436c98717423ed2930..592f5a5e7542968c21e82fb3cf861f122f5b262b 100644 (file)
--- a/libavcodec/mathops.h
+++ b/libavcodec/mathops.h
@@ -22,9 +22,15 @@
 #ifndef AVCODEC_MATHOPS_H
 #define AVCODEC_MATHOPS_H
 
+#include <stdint.h>
+
 #include "libavutil/common.h"
 #include "config.h"
 
+extern const uint32_t ff_inverse[257];
+extern const uint8_t  ff_reverse[256];
+extern const uint8_t ff_sqrt_tab[256];
+
 #if   ARCH_ARM
 #   include "arm/mathops.h"
 #elif ARCH_AVR32
@@ -185,4 +191,28 @@ if ((y) < (x)) {\
 #   define PACK_2S16(a,b)    PACK_2U16((a)&0xffff, (b)&0xffff)
 #endif
 
+#ifndef FASTDIV
+#   define FASTDIV(a,b) ((uint32_t)((((uint64_t)a) * ff_inverse[b]) >> 32))
+#endif /* FASTDIV */
+
+static inline av_const unsigned int ff_sqrt(unsigned int a)
+{
+    unsigned int b;
+
+    if (a < 255) return (ff_sqrt_tab[a + 1] - 1) >> 4;
+    else if (a < (1 << 12)) b = ff_sqrt_tab[a >> 4] >> 2;
+#if !CONFIG_SMALL
+    else if (a < (1 << 14)) b = ff_sqrt_tab[a >> 6] >> 1;
+    else if (a < (1 << 16)) b = ff_sqrt_tab[a >> 8]   ;
+#endif
+    else {
+        int s = av_log2_16bit(a >> 16) >> 1;
+        unsigned int c = a >> (s + 2);
+        b = ff_sqrt_tab[c >> (s + 8)];
+        b = FASTDIV(c,b) + (b << s);
+    }
+
+    return b - (a < b * b);
+}
+
 #endif /* AVCODEC_MATHOPS_H */