Decimal Performance, version 1.12
Copyright (c) IBM Corporation, 2009. All rights reserved. © 		Draft of 7 Apr 2009
[previous | contents | next]

decimal64 performance

These tables indicate the performance of common 64-bit operations. Please see the Introduction for explanation.

These measurements are on decNumber/decFloats version 3.56 and IDFPL version 1.0, measured 2007.10.11 and 2007.10.19 respectively.
  64-bit conversions
  Operation decDouble idfpl64   decNum
  Encoding to BCD (with exponent)
  16-digit finite 		  39       n/s       481    
  BCD to encoding (with exponent)
  16-digit finite 		  46       n/s       327    
  Encoding to string
  16-digit, with exponent 		  84       242       133    
  Exact string to encoding (unrounded)
  16-digit, with exponent 		  229       648       196    
  String to encoding (rounded)
  16-digit, rounded, with exponent 		  266       747       548    
  Widen to 128-bit
  16-digit, with exponent 		  30       51       209    
  int32 to encoding
  From most negative int 		  39       13       199    
  Encoded integer to int32
  To most negative int32 		  32       70       136    
  Encoding (any value) to int32
  16-digit, all-nines round, to uint32 		  178       165       n/s    
  64-bit miscellaneous operations
  Operation decDouble idfpl64   decNum
  Class (classify datum)
  Negative small subnormal 		  37       95       113    
  Copies (Abs/Negate/Sign)
  CopySign, copy needed 		  25       16       338    
  Count significant digits
  Single digit 		  24       n/s       122    
  Logical And/Or/Xor/Invert (digitwise)
  16-digit 		  23       n/s       510    
  Shift/Rotate
  Rotate 15 digits 		  154       n/s       583    
  64-bit computations
  Operation decDouble idfpl64   decNum
  Add (same-sign addition)
  16-digit, unaligned, rounded 		  245       247       848    
  Subtract (different-signs addition)
  16-digit, unaligned, rounded, borrow 		  288       251    
  Compare
  16-digit, unaligned, mismatch at end 		  126       151       442    
  CompareTotal
  16-digit, unaligned, mismatch at end 		  149       142       594    
  Divide
  16- by 16-digit (rounded) 		  828       556       1576    
  FMA (fused multiply-add)
  16-digit, subtraction, rounded 		  785       879       1683    
  LogB
  Negative result 		  48       66       279    
  MaxNum/MinNum
  16-digit, unaligned, mismatch at end 		  155       183       656    
  Multiply
  16×16-digit, round needed 		  362       612       1305    
  Quantize
  16-digit, round all-nines 		  112       196       422    
  ScaleB
  Underflow 		  212       221       513    
  To integral value
  16-digit, round all-nines 		  135       170       709    

[previous | contents | next]