avcodec: optimize mathops for Loongson-3 v1

HAVE_LOONGSON is replaced by HAVE_LOONGSON3. Even Loongson-2E and 2F support
Loongson SIMD instructs but have low performance for decoding. We plan to focus
on optimizing Loongson-3A1000, 3B1500 and 3A1500, and modify the configure file
to support Loongson-2 series later by adding HAVE_LOONGSON2.
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/mathops.h

@@ -211,6 +211,8 @@ if ((y) < (x)) {\
 #   define FASTDIV(a,b) ((uint32_t)((((uint64_t)a) * ff_inverse[b]) >> 32))
 #endif /* FASTDIV */
 
+#ifndef ff_sqrt
+#define ff_sqrt ff_sqrt
 static inline av_const unsigned int ff_sqrt(unsigned int a)
 {
     unsigned int b;
@@ -230,6 +232,7 @@ static inline av_const unsigned int ff_sqrt(unsigned int a)
 
     return b - (a < b * b);
 }
+#endif
 
 static inline int8_t ff_u8_to_s8(uint8_t a)
 {

libavcodec/mips/mathops.h

 /*
  * Copyright (c) 2009 Mans Rullgard <mans@mansr.com>
+ * Copyright (c) 2015 Zhou Xiaoyong <zhouxiaoyong@loongson.cn>
  *
  * This file is part of FFmpeg.
  *
@@ -27,14 +28,73 @@
 
 #if HAVE_INLINE_ASM
 
-#if HAVE_LOONGSON
+#if HAVE_LOONGSON3
+
+#define MULH MULH
+static inline av_const int MULH(int a, int b)
+{
+    int c;
+    __asm__ ("dmult %1, %2      \n\t"
+             "mflo %0           \n\t"
+             "dsrl %0, %0, 32   \n\t"
+             : "=r"(c)
+             : "r"(a),"r"(b)
+             : "hi", "lo");
+    return c;
+}
+
+#define UMULH UMULH
+static inline av_const unsigned UMULH(unsigned a, unsigned b)
+{
+    unsigned c;
+    __asm__ ("dmultu %1, %2     \n\t"
+             "mflo %0           \n\t"
+             "dsrl %0, %0, 32   \n\t"
+             : "=r"(c)
+             : "r"(a),"r"(b)
+             : "hi", "lo");
+    return c;
+}
+
+#define mid_pred mid_pred
+static inline av_const int mid_pred(int a, int b, int c)
+{
+    int t = b;
+    __asm__ ("sgt $8, %1, %2    \n\t"
+             "movn %0, %1, $8   \n\t"
+             "movn %1, %2, $8   \n\t"
+             "sgt $8, %1, %3    \n\t"
+             "movz %1, %3, $8   \n\t"
+             "sgt $8, %0, %1    \n\t"
+             "movn %0, %1, $8   \n\t"
+             : "+&r"(t),"+&r"(a)
+             : "r"(b),"r"(c)
+             : "$8");
+    return t;
+}
+
+#define ff_sqrt ff_sqrt
+static inline av_const unsigned int ff_sqrt(unsigned int a)
+{
+    unsigned int b;
+
+    __asm__ ("ctc1 %1, $f0      \n\t"
+             "sqrt.s $f2, $f0   \n\t"
+             "cvt.w.s $f0, $f2  \n\t"
+             "cfc1 %0, $f0      \n\t"
+             : "=r"(b)
+             : "r"(a));
+    return b;
+}
 
 static inline av_const int64_t MAC64(int64_t d, int a, int b)
 {
     int64_t m;
-    __asm__ ("dmult.g %1, %2, %3 \n\t"
+    __asm__ ("dmult %2, %3     \n\t"
+             "mflo  %1         \n\t"
              "daddu %0, %0, %1 \n\t"
-             : "+r"(d), "=&r"(m) : "r"(a), "r"(b));
+             : "+r"(d), "=&r"(m) : "r"(a), "r"(b)
+             : "hi", "lo");
     return d;
 }
 #define MAC64(d, a, b) ((d) = MAC64(d, a, b))
@@ -42,14 +102,16 @@ static inline av_const int64_t MAC64(int64_t d, int a, int b)
 static inline av_const int64_t MLS64(int64_t d, int a, int b)
 {
     int64_t m;
-    __asm__ ("dmult.g %1, %2, %3 \n\t"
+    __asm__ ("dmult %2, %3     \n\t"
+             "mflo  %1         \n\t"
              "dsubu %0, %0, %1 \n\t"
-             : "+r"(d), "=&r"(m) : "r"(a), "r"(b));
+             : "+r"(d), "=&r"(m) : "r"(a), "r"(b)
+             : "hi", "lo");
     return d;
 }
 #define MLS64(d, a, b) ((d) = MLS64(d, a, b))
 
-#endif
+#endif /* HAVE_LOONGSON3 */
 
 #endif /* HAVE_INLINE_ASM */