ADSP-2126x SHARC Processor Hardware Reference
3-51
Program Sequencer
For most interrupts, both internal and external, only one instruction is
executed after the interrupt occurs (and before the two aborted instruc-
tions), while the processor fetches and decodes the first instruction of the
service routine. Interrupt processing starts two cycles after an arithmetic
exception occurs because of the one cycle delay between an arithmetic
exception and the
STKYx,y
register update. There is also a three cycle
Table 3-22. Pipelined Execution Cycles for Interrupt During Delayed
Branch Instruction
Cycles
1
2
3
4
5
6
7
Execute
N – 1
1
N
N + 1
N + 2
NOP
NOP
V
Decode
N
N + 1
N + 2
J–>NOP
4
J + 1–>NOP
6
V
V + 1
Fetch
N + 1
N + 2
2
J
J + 1
3
V
5
V + 1
V + 2
N is the delayed branch instruction, J is the instruction at the branch address, and V is the
interrupt vector instruction.
1. Interrupt occurs
2. Interrupt recognized, but not processed
3. Interrupt processed
4. For a Call, N+3 (return address) is pushed onto the PC stack; J suppressed
5. Interrupt vector output
6. J pushed on PC stack; J+1 suppressed
Table 3-23. Pipelined Execution Cycles for Interrupt During Instruction
with Conflicting PM Data Access (Instruction Not Cached)
Cycles
1
2
3
4
5
6
Execute
N – 1
1
N
NOP
NOP
NOP
V
Decode
N
N + 1–>NOP
3
N + 1–>NOP
5
N + 1–>NOP
7
V
V + 1
Fetch
N + 1
—
2
N + 2
4
V
6
V + 1
V + 2
N is the delayed branch instruction, J is the instruction at the branch address, and V is the
interrupt vector instruction.
1. Interrupt occurs
2. Interrupt recognized, but not processed; PM data access
3. N+1 suppressed
4. Interrupt processed
5. N+1 suppressed
6. Interrupt vector output
7. N + 1 pushed on PC stack; N + 2 suppressed
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 ...