ADSP-BF53x/BF56x Blackfin Processor Programming Reference
D-5
Numeric Formats
Binary Multiplication
In addition and subtraction, both operands must be in the same format
(signed or unsigned, radix point in the same location), and the result for-
mat is the same as the input format. Addition and subtraction are
performed the same way whether the inputs are signed or unsigned.
In multiplication, however, the inputs can have different formats, and the
result depends on their formats. The ADSP-BF53x/BF56x Blackfin family
assembly language allows you to specify whether the inputs are both
signed, both unsigned, or one of each (mixed-mode). The location of the
radix point in the result can be derived from its location in each of the
inputs. This is shown in
Figure D-3
. The product of two 16-bit numbers
is a 32-bit number. If the inputs’ formats are M.N and P.Q, the product
has the format (M + P).(N + Q). For example, the product of two 13.3
numbers is a 26.6 number. The product of two 1.15 numbers is a 2.30
number.
Figure D-3. Format of Multiplier Result
General Rule
4-bit Example
16-bit Examples
M.N
x P.Q
(M + P).(N + Q)
1.111 (1.3 Format)
x 11.11 (2.2 Format)
1111
1111
1111
1111
111.00001 (3.5 Format = (1 + 2).(2 + 3) )
5.3
x 5.3
10.6
1.15
x 1.15
2.30
Содержание ADSP-BF53x Blackfin
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Страница 324: ...Instruction Overview 7 20 ADSP BF53x BF56x Blackfin Processor Programming Reference...
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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...