ADSP-2126x SHARC Processor Hardware Reference
2-31
Processing Elements
• Bit field manipulation operations, including extract and deposit
• Fixed-point/floating-point conversion operations, including expo-
nent extract, number of leading 1s or 0s
Shifter Operation
The shifter takes from one to three inputs: X input, Y input, and Z input.
The inputs (also known as operands) can be any register in the register
file. Within a shifter instruction, the inputs serve as follows.
• The X input provides data that is operated on.
• The Y input specifies shift magnitudes, bit field lengths, or bit
positions.
• The Z input provides data that is operated on and updated.
In the following example,
Rx
is the X input,
Ry
is the Y input, and
Rn
is the
Z input. The shifter returns one output (
Rn
) to the register file.
Rn
=
Rn
OR LSHIFT
Rx
BY
Ry
;
As shown in
, the shifter fetches input operands from the upper
32 bits of a register file location (bits 39-8) or from an immediate value in
the instruction. The shifter transfers operands during the first half of the
cycle and transfers the result to the upper 32 bits of a register (with the
eight LSBs zero-filled) during the second half of the cycle. With this
arrangement, the shifter can read and write the same register file location
in a single cycle.
The X input and Z input are always 32-bit fixed-point values. The Y input
is a 32-bit fixed-point value or an 8-bit field (shf8), positioned in the reg-
ister file. These inputs appear in
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 ...