Accessing Memory
5-28
ADSP-2126x SHARC Processor Hardware Reference
Mode 2 Register Control Bits
The following bits in the
MODE2
register control memory access modes:
•
Illegal IOP Register Access Enable.
MODE2
Bit 20 (
IIRAE
) enables
detection of IOP register access (if 1) or disables detection (if 0).
•
Unaligned 64-bit Memory Access Enable.
MODE2
Bit 21 (
U64MAE
)
enables detection of uneven address memory access (if 1) or dis-
ables detection (if 0).
SISD, SIMD, and Broadcast Load Modes
These modes influence memory accesses. For a comparison of their effects,
see the examples in
“Internal Memory Access Listings” on page 5-30
. and
“Secondary Processor Element (PEy)” on page 5-19
.
Broadcast load mode is a hybrid between SISD and SIMD modes that
transfers dual-data under special conditions. For examples of broadcast
transfers, see
“Internal Memory Access Listings” on page 5-30
. For more
information on broadcast load mode, see
.
Single- and Dual-Data Accesses
The number of transfers that occur in a cycle influences the data access
operation. As described in
“DSP Architecture” on page 5-2
, the DSP sup-
ports single cycle, dual-data accesses to and from internal memory for
register-to-memory and memory-to-register transfers. Dual-data accesses
occur over the PM and DM bus and act independent of SIMD/SISD.
Though only available for transfers between memory and data registers,
dual-data transfers are extremely useful because they double the data
throughput over single-data 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 ...