ADSP-BF53x/BF56x Blackfin Processor Programming Reference
5-15
Address Arithmetic Unit
In equation form, these post-modify and wraparound operations work as
follows, shown for “I+M” operations.
• If M is positive:
I
new
= I
old
+ M
if I
old
+ M < buffer base + length (end of buffer)
I
new
= I
old
+ M – L
if I
old
+ M
≥
buffer base + length (end of buffer)
• If M is negative:
I
new
= I
old
+ M
if I
old
+ M
≥
buffer base (start of buffer)
I
new
= I
old
+ M + L
if I
old
+ M < buffer base (start of buffer)
Addressing With Bit-reversed Addresses
To obtain results in sequential order, programs need bit-reversed carry
addressing for some algorithms, particularly Fast Fourier Transform
(FFT) calculations. To satisfy the requirements of these algorithms, the
DAG’s bit-reversed addressing feature permits repeatedly subdividing data
sequences and storing this data in bit-reversed order. For detailed infor-
mation about bit-reversed addressing, see
“Modify – Increment” on
page 15-37
.
Modifying DAG and Pointer Registers
The DAGs support operations that modify an address value in an Index
register without outputting an address. The operation, address-modify, is
useful for maintaining pointers.
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...
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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...