Branches and Sequencing
4-10
ADSP-BF535 Blackfin Processor Hardware Reference
• A return instruction causes the Sequencer to fetch the instruction
at the return address, which is stored in the
RETS
register (for sub-
routine returns). The types of return instructions are return from
subroutine (
RTS
), return from interrupt (
RTI
), return from excep-
tion (
RTX
), return from emulation (
RTE
), and return from
non-maskable interrupt (
RTN
). Each return type has its own register
for holding the return address.
•
JUMP
instructions can be conditional, depending on the status of
the
CC
bit of the
ASTAT
register. They are immediate and may not
be delayed. The Program Sequencer can evaluate the
CC
status bit
to decide whether to execute a branch. If no condition is specified,
the branch is always taken.
• Conditional
JUMP
instructions use static branch prediction to
reduce the branch latency because of the effects of the pipeline.
Branches can be direct or indirect. The difference is that the Sequencer
generates the address for a direct branch, for example
JUMP 0x30
, and the
Data Address Generator produces the address for an indirect branch, for
example
JUMP (P3)
.
Direct branches are
JUMP
or
CALL
instructions that use a PC-relative
address.
Indirect branches are
JUMP
or
CALL
instructions that use a dynamic
address—an address that changes at runtime—that comes from a Data
Address Generator. For more information, see
“Data Address Generators”
on page 5-1
.
Summary of Contents for ADSP-BF535 Blackfin
Page 80: ...Development Tools 1 26 ADSP BF535 Blackfin Processor Hardware Reference...
Page 312: ...Working With Memory 6 86 ADSP BF535 Blackfin Processor Hardware Reference...
Page 332: ...System Interfaces 7 20 ADSP BF535 Blackfin Processor Hardware Reference...
Page 360: ...Dynamic Power Management Controller 8 28 ADSP BF535 Blackfin Processor Hardware Reference...
Page 446: ...Beginning and Ending an SPI Transfer 10 40 ADSP BF535 Blackfin Processor Hardware Reference...
Page 522: ...Timing Examples 11 76 ADSP BF535 Blackfin Processor Hardware Reference...
Page 562: ...IrDA Support 12 40 ADSP BF535 Blackfin Processor Hardware Reference...
Page 608: ...PCI I O Issues 13 46 ADSP BF535 Blackfin Processor Hardware Reference...
Page 672: ...References 14 64 ADSP BF535 Blackfin Processor Hardware Reference...
Page 810: ...SDRAM Controller SDC 18 86 ADSP BF535 Blackfin Processor Hardware Reference...
Page 811: ...ADSP BF535 Blackfin Processor Hardware Reference 18 87 External Bus Interface Unit...
Page 812: ...SDRAM Controller SDC 18 88 ADSP BF535 Blackfin Processor Hardware Reference...
Page 860: ...DMA Bus Debug Registers 20 30 ADSP BF535 Blackfin Processor Hardware Reference...