Data Types
2-16
ADSP-BF535 Blackfin Processor Hardware Reference
Using Multiplier Integer and Fractional Formats
For multiply-and-accumulate functions, the ADSP-BF535 processor pro-
vides two choices: fractional arithmetic for fractional numbers (1.15) and
integer arithmetic for integers (16.0).
For fractional arithmetic, the 32-bit product output is format adjusted—
sign extended and shifted one bit to the left—before being added to accu-
mulator
A0
or
A1
. For example, bit 31 of the product lines up with bit 32
of
A0
(which is bit 0 of
A0.X
), and bit 0 of the product lines up with bit 1
of
A0
(which is bit 1 of
A0.W
). The LSB is zero filled. The fractional multi-
plier result format appears in
Figure 2-4
.
For integer arithmetic, the 32-bit product register is not shifted before
being added to
A0
or
A1
.
Figure 2-5
shows the integer mode result
placement.
With either fractional or integer operations, the multiplier output product
is fed into a 40-bit adder/subtracter which adds or subtracts the new prod-
uct with the current contents of the
A0
or
A1
register to produce the final
40-bit result.
Table 2-6. Shifter Arithmetic Formats
Operation
Operand Formats
Result Formats
Logical Shift
Unsigned binary string
Same as operands
Arithmetic Shift
Signed
Same as operands
Exponent Detect
Signed
Same as operands
Содержание ADSP-BF535 Blackfin
Страница 80: ...Development Tools 1 26 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 312: ...Working With Memory 6 86 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 332: ...System Interfaces 7 20 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 360: ...Dynamic Power Management Controller 8 28 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 446: ...Beginning and Ending an SPI Transfer 10 40 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 522: ...Timing Examples 11 76 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 562: ...IrDA Support 12 40 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 608: ...PCI I O Issues 13 46 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 672: ...References 14 64 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 810: ...SDRAM Controller SDC 18 86 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 811: ...ADSP BF535 Blackfin Processor Hardware Reference 18 87 External Bus Interface Unit...
Страница 812: ...SDRAM Controller SDC 18 88 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 860: ...DMA Bus Debug Registers 20 30 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 908: ...SDRAM Controller External Bus Interface Unit B 36 ADSP BF535 Blackfin Processor Hardware Reference...