SIMD Mode and Sequencing
3-38
ADSP-2126x SHARC Processor Hardware Reference
Conditional Compute Operations
While in SIMD mode, a conditional compute operation can execute on
both processing elements, either element, or neither element, depending
on the outcome of the status flag test. Flag testing is independently per-
formed on each processing element.
Conditional Branches and Loops
The DSP executes a conditional branch (
JUMP
or
CALL
/
RETURN
) or loop
(
DO/UNTIL
) based on the result of ANDing the condition tests on both PEx
and PEy. A conditional branch or loop in SIMD mode occurs only when
the condition is true in PEx and PEy.
Using complementary conditions (for example
EQ
and
NE
), programs can
produce an ORing of the condition tests for branches and loops in SIMD
mode. A conditional branch or loop that uses this technique must consist
of a series of conditional compute operations. These conditional computes
generate
NOP
s on the processing element where a branch or loop does not
execute. For more information on programming in SIMD mode, see
SHARC Processor Programming Reference
.
Conditional Data Moves
The execution of a conditional (
IF
) data move (register-to-register and
register-to/from-memory) instruction depends on three factors:
• The explicit data move depends on the evaluation of the condi-
tional test in the PEx processing element.
• The implicit data move depends on the evaluation of the condi-
tional test in the PEy processing element.
• Both moves depend on the types of registers used in the move.
There are four cases for SIMD conditional data moves.
Summary of Contents for ADSP-21261 SHARC
Page 30: ...Contents xxx ADSP 2126x SHARC Processor Hardware Reference ...
Page 40: ...Register Diagram Conventions xl ADSP 2126x SHARC Processor Hardware Reference ...
Page 58: ...Differences From Previous SHARCs 1 18 ADSP 2126x SHARC Processor Hardware Reference ...
Page 112: ...Secondary Processing Element PEy 2 54 ADSP 2126x SHARC Processor Hardware Reference ...
Page 178: ...Summary 3 66 ADSP 2126x SHARC Processor Hardware Reference ...
Page 204: ...DAG Instruction Summary 4 26 ADSP 2126x SHARC Processor Hardware Reference ...
Page 322: ...Setting Up DMA 7 32 ADSP 2126x SHARC Processor Hardware Reference ...
Page 436: ...SPORT Programming Examples 9 86 ADSP 2126x SHARC Processor Hardware Reference ...
Page 521: ...ADSP 2126x SHARC Processor Hardware Reference 11 31 Input Data Port rts IDP_ISR end ...
Page 522: ...Input Data Port Programming Example 11 32 ADSP 2126x SHARC Processor Hardware Reference ...
Page 590: ...Timer Programming Examples 14 20 ADSP 2126x SHARC Processor Hardware Reference ...
Page 796: ...I O Processor Registers A 174 ADSP 2126x SHARC Processor Hardware Reference ...
Page 800: ...B 4 ADSP 2126x SHARC Processor Core Manual ...
Page 846: ...Index I 36 ADSP 2126x SHARC Processor Hardware Reference ...