
ADSP-2126x SHARC Processor Hardware Reference
3-49
Program Sequencer
this table are spaced at 4-instruction intervals. Each interrupt vector has
associated latch and mask bits. For a list of interrupt vector addresses and
their associated latch and mask bits, see
“Interrupt Register (LIRPTL)” on page A-30
,
, and
“Interrupt Latch Register (IRPTL)” on
lists the latch and mask bits.
To process an interrupt, the DSP’s program sequencer:
1. outputs the appropriate interrupt vector address.
2. pushes the current PC value (the return address) onto the PC stack.
3. pushes the current value of the
ASTATx/y
and
MODE1
registers onto
the status stack (if the interrupt is
IRQ2–0
, or timer).
4. resets the appropriate bit in the interrupt latch register (
IRPTL
and
LIRPTL
registers).
5. alters the interrupt mask pointer bits (
IMASKP
) to reflect the current
interrupt nesting state, depending on the nesting mode.
At the end of the interrupt service routine (ISR), the sequencer processes
the return-from-interrupt (
RTI
) instruction and performs the steps shown
below. Between servicing and returning, the sequencer clears the latch bit
of the in-progress ISR every cycle until the
RTI
is executed. This prevents
the same interrupt from recurring until the ISR is done. Refer to the
JUMP
(
CI
) code example
to learn how to prevent this clearing.
1. Returns to the address stored at the top of the PC stack.
2. Pops this value off the PC stack.
3. Pops the status stack (if the
ASTATx,y
and
MODE1
status registers
were pushed for the
IRQ2–0
, or timer interrupt).
4. Clears the appropriate bit in the interrupt mask pointer (
IMASKP
).
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 ...