Using Memory Access Status
5-22
ADSP-2126x SHARC Processor Hardware Reference
Using Memory Access Status
As described in
“Illegal I/O Processor Register Access” on page 5-21
and
“Unaligned 64-Bit Memory Access” on page 5-21
illegal access information for long word or I/O register accesses. When
these conditions occur, the DSP updates an illegal condition flag in a
sticky status (
STKYx
) register. Either of these two conditions can also gen-
erate a maskable interrupt. Two ways to use illegal access information are:
•
Interrupts.
Enable interrupts and use an interrupt service routine
(ISR) to handle the illegal access condition immediately. This
method is appropriate if it is important to handle all illegal accesses
as they occur.
•
STKYx registers.
Sticky registers hold a value that can be checked
for a specific condition at a later time. Use the
Bit
Tst
instruction
to examine illegal condition flags in the
STKYx
register after an
interrupt to determine which illegal access condition occurred.
Accessing Memory
The word width of DSP processor core accesses to internal memory
include:
• 48-bit access for instruction words, extended-precision normal
word (40-bit) data, and
PX
register
• 64-bit access for long word data, normal word (32-bit) data, or
PX
register data with the
LW
mnemonic
• 32-bit access for normal word (32-bit) data
• 16-bit access for short word data
The DSP determines whether a normal word access is 32 or 40 bits from
the internal memory block’s
IMDWx
setting.
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 ...