dsp56800e Freescale Semiconductor, Inc, dsp56800e Datasheet - Page 230

• Manufacturer Part Number: dsp56800e
• Description: 16-bit Digital Signal Controller Core
• Manufacturer: Freescale Semiconductor, Inc

Bit-Manipulation Unit
7.1
The bit-manipulation unit contains the following:
A block diagram of the bit-manipulation unit appears in Figure 7-1.
The blocks within the bit-manipulation unit are explained in the following sections.
7.1.1
The 8-bit mask shift unit performs two dedicated functions:
This shifter is used when the BRCLR and BRSET instructions are executed. These instructions test only
the upper or lower byte of a word. See Example 7-1 on page 7-3.
7-2
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8-bit mask shifting unit
16-bit masking unit
16-bit testing unit
16-bit logic unit
Right shifting an 8-bit immediate mask from the upper byte of a word to the lower byte of a word,
zeroing the upper 8 bits of the mask
Passing the upper 8 bits of the immediate mask to the 16-bit masking unit, zeroing out the lower
8 bits of the mask
Architecture
Bit-Manipulation Unit Overview and
8-Bit Mask Shift Unit
CDBR
CDBW
DSC Core
Registers
Figure 7-1. Bit-Manipulation Unit Block Diagram
DSP56800E Core Reference Manual
Bit-Manipulation Unit
Optional 8-Bit Mask Shift
Data Memory
Test with 16-Bit Mask
16-Bit Masking Unit
Locations
16-Bit Logic Unit
PDB
Interface
IP-BUS
Peripheral
Registers
Freescale Semiconductor
To Carry Bit
in the
Status Register