Data Register File
2-38
ADSP-2126x SHARC Processor Hardware Reference
Data Register File
Each of the DSP’s processing elements has a data register file, which is a
set of data registers that transfers data between the data buses and the
computational units. These registers also provide local storage for oper-
ands and results.
The two register files consist of 16 primary registers and 16 alternate (sec-
ondary) registers. All of the data registers are 40 bits wide. Within these
registers, 32-bit data is always left-justified. If an operation specifies a
32-bit data transfer to these 40-bit registers, the eight LSBs are ignored on
register reads, and the LSBs are cleared to zeros on writes.
Program memory data accesses and data memory accesses to/from the reg-
ister file(s) occur on the PM data bus and DM data bus, respectively. One
PM data bus access for each processing element and/or one DM data bus
access for each processing element can occur in one cycle. Transfers
between the register files and the DM or PM data buses can move up to
64 bits of valid data on each bus.
If an operation specifies the same register file location as both an input
and output, the read occurs in the first half of the cycle and the write in
the second half. With this arrangement, the DSP uses the old data as the
operand, before updating the location with the new result data. If writes
to the same location take place in the same cycle, only the write with
higher precedence actually occurs. The DSP determines precedence for
the write operation from the source of the data; from highest to lowest,
the precedence is:
1. Data memory or universal register (
Ureg
)
2. Program memory
3. PEx ALU
4. PEy ALU
Содержание ADSP-21261 SHARC
Страница 30: ...Contents xxx ADSP 2126x SHARC Processor Hardware Reference ...
Страница 40: ...Register Diagram Conventions xl ADSP 2126x SHARC Processor Hardware Reference ...
Страница 58: ...Differences From Previous SHARCs 1 18 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 112: ...Secondary Processing Element PEy 2 54 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 178: ...Summary 3 66 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 204: ...DAG Instruction Summary 4 26 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 322: ...Setting Up DMA 7 32 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 436: ...SPORT Programming Examples 9 86 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 521: ...ADSP 2126x SHARC Processor Hardware Reference 11 31 Input Data Port rts IDP_ISR end ...
Страница 522: ...Input Data Port Programming Example 11 32 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 590: ...Timer Programming Examples 14 20 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 796: ...I O Processor Registers A 174 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 800: ...B 4 ADSP 2126x SHARC Processor Core Manual ...
Страница 846: ...Index I 36 ADSP 2126x SHARC Processor Hardware Reference ...