D950-CORE datasheet(16/89 Pages) STMICROELECTRONICS

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D950-Core

4.1.4 Barrel Shifter Unit (BSU)

The D950-Core BSU provides a complete set of shifting functions

Arithmetic shift: 40-bit input (either a 32 bit operand sign extended to 40-bit, or a 40-bit

accumulator), providing a valid result

Logical shift: provides a 32-bit result which is loaded into a 40-bit accumulator, the 8-bit

extension of which is reset.

Rotation:

8-bit EXT/sign

16-bit MSB

16-bit LSB

TST

8-bit EXT/sign

16-bit MSB

16-bit LSB

TST

Right: shifts the 40-bit input data to the right, the upper part is sign extended

Left: shifts the 40-bit input data to the left, the upper part is fed by 0

8-bit EXT = 0

16-bit MSB

16-bit LSB

TST

8-bit EXT = 0

16-bit MSB

16-bit LSB

TST

Right: shifts the 32-bit input data to the right, the upper part is fed by 0

Left: shifts the 32-bit input data to the left, the upper part is fed by 0

8-bit EXT = 0

16-bit MSB

16-bit LSB

16-bit MSB

16-bit LSB

TST

Right: rotates the input data to the right (only through the BSC register)

Left with TST: rotates the 33-bit data made of the concatenation of TST-bit

Left: rotates the 32-bit input data to the left

TST

of CCR with the 32-bit input data to the left (the LSB of the 32-bit input is

fed by TST-bit, the MSB of the 32-bit input feeds the TST-bit of CCR).

D950-CORE Datasheet(PDF) 16 Page - STMicroelectronics