ADSP-BF535 Blackfin Processor Hardware Reference
4-9
Program Sequencer
Register File reads occur in the EX1 pipeline stage (for operands) and the
EX3 pipeline stage (for stores). Writes occur in the WB stage. The multi-
pliers and the video unit are active in the EX2 stage, and the ALUs and
shifter are active in the EX3 stage. The accumulators are written at the end
of the EX3 stage.
Any nonsequential program flow can potentially decrease the processor’s
instruction throughput. Nonsequential program operations include:
• Program memory data accesses that conflict with instruction
fetches
• Jumps
• Subroutine calls and returns
• Interrupts and returns
• Loops
Branches and Sequencing
One type of nonsequential program flow that the Sequencer supports is
branching. A branch occurs when a
JUMP
or
CALL
instruction begins execu-
tion at a new location other than the next sequential address. For
descriptions of how to use the
JUMP
and
CALL
instructions, see
Blackfin
Processor Programming Reference
. Briefly, these instructions operate as
follows:
• A
JUMP
or a
CALL
instruction transfers program flow to another
memory location. The difference between a
JUMP
and a
CALL
is that
a
CALL
automatically loads the return address into the
RETS
register.
The return address is the next sequential address after the
CALL
instruction. This push makes the address available for the
CALL
instruction’s matching return instruction, allowing easy return
from the subroutine.
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...