Data Types
2-22
ADSP-BF53x/BF56x Blackfin Processor Programming Reference
Biased Rounding
The round-to-nearest method also returns the number closest to the origi-
nal. However, by convention, an original number lying exactly halfway
between two numbers always rounds up to the larger of the two. For
example, when rounding the 3-bit, two’s-complement fraction 0.25
(binary 0.01) to the nearest 2-bit, two’s-complement fraction, this method
returns 0.5 (binary 0.1). The original fraction lies exactly midway between
0.5 and 0.0 (binary 0.0), so this method rounds up. Because it always
rounds up, this method is called biased rounding.
Figure 2-8. Avoiding Net Bias in Unbiased Multiplier Rounding
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
X X X X X X X X 0
1
1
0
0
1
1
0
X X X X X X X X
UNROUNDED VALUE:
A0.X
A0.W
1
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ADD 1 AND CARRY:
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
X X X X X X X X 0
1
1
0
0
1
1
0
X X X X X X X X
ROUNDED VALUE:
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
X X X X X X X X 0
1
1
0
0
1
1
1
X X X X X X X X
A0 BIT 16 = 1:
Содержание ADSP-BF53x Blackfin
Страница 38: ...Conventions xxxviii ADSP BF53x BF56x Blackfin Processor Programming Reference...
Страница 134: ...System Reset and Powerup 3 18 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Страница 324: ...Instruction Overview 7 20 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Страница 486: ...Instruction Overview 13 28 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Страница 512: ...Instruction Overview 14 26 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Страница 604: ...Instruction Overview 15 92 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Страница 688: ...Instruction Overview 18 48 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Страница 742: ...Instruction Overview 19 54 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Страница 752: ...Examples 20 10 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Страница 780: ...Product Identification Register 21 28 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Страница 790: ...ADSP BF535 Flags A 10 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Страница 800: ...Performance Monitor Registers B 10 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Страница 994: ...Instructions Listed By Operation Code C 194 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Страница 1042: ...Index I 40 ADSP BF53x BF56x Blackfin Processor Programming Reference...