Buses
5-6
ADSP-2126x SHARC Processor Hardware Reference
Because the DSP’s internal memory is arranged in four 16-bit wide by
96K columns, memory is addressable in widths that are multiples of col-
umns up to 64 bits:
1 column = 16-bit words
2 columns = 32-bit words
3 columns = 48- or 40-bit words
4 columns = 64-bit words
For more information on the how the DSP works with memory words, see
“Memory Organization and Word Size” on page 5-12
.
The PM and DM data buses are 64 bits wide. Both data buses can handle
long word (64-bit), normal word (32-bit), Extended-precision normal
word (40-bit), and short word (16-bit) data, but only the PM data bus
carries instruction words (48-bit).
Internal Data Bus Exchange
The data buses allow programs to transfer the contents of any register in
the DSP to any other register or to any internal memory location in a sin-
gle cycle. As shown in
, the PM Bus Exchange (
PX
) register
permits data to flow between the PM and DM data buses. The
PX
register
can work as one 64-bit register or as two 32-bit registers (
PX1
and
PX2
).
The alignment of
PX1
and
PX2
within
PX
appears in
The
PX1
,
PX2
, and the combined
PX
registers are Universal registers (
Ureg
)
that are accessible for register-to-register or memory-to-register transfers.
The
PX
register-to-register transfers using data registers are either 40-bit
transfers for the combined
PX
or 32-bit transfers for
PX1
or
PX2
shows the bit alignment and gives an example of instructions for regis-
ter-to-register transfers.
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 ...