
Core Registers
A-16
ADSP-2126x SHARC Processor Hardware Reference
Sticky Status Registers (STKYx and STKYy)
These are non memory-mapped, universal, system registers (
Ureg
and
Sreg
). Each processing element has its own
STKY
register. The
STKYx
regis-
ter indicates status for PEx operations and some program sequencer stacks.
The
STKYy
register only indicates status for PEy operations.
STKY
bits do not clear themselves after the condition they flag is no
longer true. They remain “sticky” until cleared by the program.
The processor sets a
STKY
bit in response to a condition. For example, the
processor sets the
AUS
bit in the
STKY
register when an ALU underflow set
AZ
in the
ASTAT
register. The processor clears
AZ
if the next ALU operation
does not cause an underflow. The
AUS
bit remains set until a program
clears the
STKY
bit. Interrupt service routines (ISRs) must clear their inter-
rupt’s corresponding
STKY
bit so the processor can detect a reoccurrence of
the condition. For example, an ISR for a floating-point underflow excep-
tion interrupt (
FLTUI
) clears the
AUS
bit in the
STKY
register near the
beginning of the routine.
, and
provide
bit information for both the
STKYx
and
STKYy
registers.
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 ...