efDataDiscreteRateMining varianceDataMemoryDefinition.c 吉超博 commit at 2020-09-08

efDataDiscreteRateMining/dataSharedMemory/varianceDataMemoryDefinition.c

@@ -170,3 +170,62 @@ shifted into the proper positions, the three fields are simply added
 together to form the result.  This means that any integer portion of `zSig'
 will be added into the exponent.  Since a properly normalized significand
 will have an integer portion equal to 1, the `zExp' input should be 1 less
+than the desired result exponent whenever `zSig' is a complete, normalized
+significand.
+-------------------------------------------------------------------------------
+*/
+INLINE float32 packFloat32( flag zSign, int16 zExp, bits32 zSig )
+{
+#if 0
+   float32 f;
+   __asm__("@ packFloat32				\n\
+   	    mov %0, %1, asl #31				\n\
+   	    orr %0, %2, asl #23				\n\
+   	    orr %0, %3"
+   	    : /* no outputs */
+   	    : "g" (f), "g" (zSign), "g" (zExp), "g" (zSig)
+   	    : "cc");
+   return f;
+#else
+    return ( ( (bits32) zSign )<<31 ) + ( ( (bits32) zExp )<<23 ) + zSig;
+#endif 
+}
+
+/*
+-------------------------------------------------------------------------------
+Takes an abstract floating-point value having sign `zSign', exponent `zExp',
+and significand `zSig', and returns the proper single-precision floating-
+point value corresponding to the abstract input.  Ordinarily, the abstract
+value is simply rounded and packed into the single-precision format, with
+the inexact exception raised if the abstract input cannot be represented
+exactly.  If the abstract value is too large, however, the overflow and
+inexact exceptions are raised and an infinity or maximal finite value is
+returned.  If the abstract value is too small, the input value is rounded to
+a subnormal number, and the underflow and inexact exceptions are raised if
+the abstract input cannot be represented exactly as a subnormal single-
+precision floating-point number.
+    The input significand `zSig' has its binary point between bits 30
+and 29, which is 7 bits to the left of the usual location.  This shifted
+significand must be normalized or smaller.  If `zSig' is not normalized,
+`zExp' must be 0; in that case, the result returned is a subnormal number,
+and it must not require rounding.  In the usual case that `zSig' is
+normalized, `zExp' must be 1 less than the ``true'' floating-point exponent.
+The handling of underflow and overflow follows the IEC/IEEE Standard for
+Binary Floating-point Arithmetic.
+-------------------------------------------------------------------------------
+*/
+static float32 roundAndPackFloat32( struct roundingData *roundData, flag zSign, int16 zExp, bits32 zSig )
+{
+    int8 roundingMode;
+    flag roundNearestEven;
+    int8 roundIncrement, roundBits;
+    flag isTiny;
+
+    roundingMode = roundData->mode;
+    roundNearestEven = ( roundingMode == float_round_nearest_even );
+    roundIncrement = 0x40;
+    if ( ! roundNearestEven ) {
+        if ( roundingMode == float_round_to_zero ) {
+            roundIncrement = 0;
+        }
+        else {