Merge commit '3edac01f79a08635d8d2c08e9410651d9a330d61'

[ffmpeg] / libavutil / softfloat.h

diff --git a/libavutil/softfloat.h b/libavutil/softfloat.h
index 00ff4a1db1bcb11b034ffc6f8ee0b9ebf4bb134c..7488753d646bacd42611515d5fab32804d254905 100644 (file)
--- a/libavutil/softfloat.h
+++ b/libavutil/softfloat.h
@@ -36,7 +36,7 @@ typedef struct SoftFloat{
     int32_t  exp;
 }SoftFloat;
 
-static const SoftFloat FLOAT_0          = {          0,   0};
+static const SoftFloat FLOAT_0          = {          0,   MIN_EXP};
 static const SoftFloat FLOAT_05         = { 0x20000000,   0};
 static const SoftFloat FLOAT_1          = { 0x20000000,   1};
 static const SoftFloat FLOAT_EPSILON    = { 0x29F16B12, -16};
@@ -90,7 +90,7 @@ static inline av_const SoftFloat av_normalize1_sf(SoftFloat a){
 }
 
 /**
- * @return Will not be more denormalized than a+b. So if either input is
+ * @return Will not be more denormalized than a*b. So if either input is
  *         normalized, then the output will not be worse then the other input.
  *         If both are normalized, then the output will be normalized.
  */
@@ -98,7 +98,10 @@ static inline av_const SoftFloat av_mul_sf(SoftFloat a, SoftFloat b){
     a.exp += b.exp;
     av_assert2((int32_t)((a.mant * (int64_t)b.mant) >> ONE_BITS) == (a.mant * (int64_t)b.mant) >> ONE_BITS);
     a.mant = (a.mant * (int64_t)b.mant) >> ONE_BITS;
-    return av_normalize1_sf((SoftFloat){a.mant, a.exp - 1});
+    a = av_normalize1_sf((SoftFloat){a.mant, a.exp - 1});
+    if (!a.mant || a.exp < MIN_EXP)
+        return FLOAT_0;
+    return a;
 }
 
 /**
@@ -108,20 +111,27 @@ static inline av_const SoftFloat av_mul_sf(SoftFloat a, SoftFloat b){
 static inline av_const SoftFloat av_div_sf(SoftFloat a, SoftFloat b){
     a.exp -= b.exp;
     a.mant = ((int64_t)a.mant<<(ONE_BITS+1)) / b.mant;
-    return av_normalize1_sf(a);
+    a = av_normalize1_sf(a);
+    if (!a.mant || a.exp < MIN_EXP)
+        return FLOAT_0;
+    return a;
 }
 
 static inline av_const int av_cmp_sf(SoftFloat a, SoftFloat b){
     int t= a.exp - b.exp;
-    if(t<0) return (a.mant >> (-t)) -  b.mant      ;
-    else    return  a.mant          - (b.mant >> t);
+    if      (t <-31) return                  -  b.mant      ;
+    else if (t <  0) return (a.mant >> (-t)) -  b.mant      ;
+    else if (t < 32) return  a.mant          - (b.mant >> t);
+    else             return  a.mant                         ;
 }
 
 static inline av_const int av_gt_sf(SoftFloat a, SoftFloat b)
 {
     int t= a.exp - b.exp;
-    if(t<0) return (a.mant >> (-t)) >  b.mant      ;
-    else    return  a.mant          > (b.mant >> t);
+    if      (t <-31) return 0                >  b.mant      ;
+    else if (t <  0) return (a.mant >> (-t)) >  b.mant      ;
+    else if (t < 32) return  a.mant          > (b.mant >> t);
+    else             return  a.mant          >  0           ;
 }
 
 static inline av_const SoftFloat av_add_sf(SoftFloat a, SoftFloat b){
@@ -143,7 +153,12 @@ static inline av_const SoftFloat av_sub_sf(SoftFloat a, SoftFloat b){
  * @returns a SoftFloat with value v * 2^frac_bits
  */
 static inline av_const SoftFloat av_int2sf(int v, int frac_bits){
-    return av_normalize_sf((SoftFloat){v, ONE_BITS + 1 - frac_bits});
+    int exp_offset = 0;
+    if(v == INT_MIN){
+        exp_offset = 1;
+        v>>=1;
+    }
+    return av_normalize_sf(av_normalize1_sf((SoftFloat){v, ONE_BITS + 1 - frac_bits + exp_offset}));
 }
 
 /**
@@ -163,7 +178,9 @@ static av_always_inline SoftFloat av_sqrt_sf(SoftFloat val)
     int tabIndex, rem;
 
     if (val.mant == 0)
-        val.exp = 0;
+        val.exp = MIN_EXP;
+    else if (val.mant < 0)
+        abort();
     else
     {
         tabIndex = (val.mant - 0x20000000) >> 20;