Loops and Sequencing
3-30
ADSP-2126x SHARC Processor Hardware Reference
Processing of an interrupt that occurs during the last iteration of a one
instruction loop is delayed by one cycle when:
• the loop executes once or twice,
• a two instruction loop executes once, or
• a
NOP
cycle follows one of these loops.
Table 3-12. Pipelined Execution Cycles for Two Instruction Counterbased
Loop with Two Iterations
Cycles
1
2
3
4
5
6
Execute
N
1
N + 1 (Pass 1) N + 2 (Pass 1) N + 1 (Pass 2) N + 2 (Pass 2) N + 3
Decode
N + 1
N + 21
N + 1
N + 2
N + 3
N + 4
Fetch
N + 2
N + 1
2
N + 2
3
N + 3
4
N + 4
N + 5
N is the loop start instruction and N + 3 is the instruction after the loop.
1. Loop count (LCNTR) equals 2
2. PC Stack supplies loop start address
3. Count expired tests true
4. Loop iteration aborts; PC and loop stacks pop
Table 3-13. Pipelined Execution Cycles for Two Instruction Counterbased
Loop with One Iteration (Two Overhead Cycles)
Cycles
1
2
3
4
5
6
Execute
N
1
N + 1 (Pass 1) N + 1 (Pass 1) NOP
NOP
N + 3
Decode
N + 1
N + 2
N + 1 –>
NOP
4
N + 2 –>
NOP
5
N + 3
N + 4
Fetch
N + 2
N + 1
2
N + 2
3
N + 3
N + 4
N + 5
N is the loop start instruction and N + 3 is the instruction after the loop.
1. Loop count (LCNTR) equals 1
2. PC Stack supplies loop start address
3. Count expired tests true
4. Loop iteration aborts; PC and loop stacks pop; N + 1 suppressed
5. N + 2 suppressed
Содержание ADSP-21261 SHARC
Страница 30: ...Contents xxx ADSP 2126x SHARC Processor Hardware Reference ...
Страница 40: ...Register Diagram Conventions xl ADSP 2126x SHARC Processor Hardware Reference ...
Страница 58: ...Differences From Previous SHARCs 1 18 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 112: ...Secondary Processing Element PEy 2 54 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 178: ...Summary 3 66 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 204: ...DAG Instruction Summary 4 26 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 322: ...Setting Up DMA 7 32 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 436: ...SPORT Programming Examples 9 86 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 521: ...ADSP 2126x SHARC Processor Hardware Reference 11 31 Input Data Port rts IDP_ISR end ...
Страница 522: ...Input Data Port Programming Example 11 32 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 590: ...Timer Programming Examples 14 20 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 796: ...I O Processor Registers A 174 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 800: ...B 4 ADSP 2126x SHARC Processor Core Manual ...
Страница 846: ...Index I 36 ADSP 2126x SHARC Processor Hardware Reference ...