dsp56800e Freescale Semiconductor, Inc, dsp56800e Datasheet - Page 149

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

5.1.1
There are three independent 16-bit registers—X0, Y1, and Y0—that serve as data registers for operations
in the data ALU. The 16-bit Y1 register and the 16-bit Y0 register can be concatenated together to form a
32-bit register called Y, which is shown in Figure 5-3 on page 5-4. Y1 forms the most significant word and
Y0 forms the least significant word.
Freescale Semiconductor
CDBW
CDBR
XDB2
*
*
For second access on dual parallel read
Data Registers (X0, Y1, Y0)
Limiter
(accesses X0 and C only)
Optional Inverter
Shifter/MUX
Latch
Figure 5-2. Data ALU Block Diagram
OMR’s SA Bit
Rounding Constant
Data Arithmetic Logic Unit
Condition Codes to Status Register
35
Arithmetic/Logical
A2
B2
C2
D2
32
Shifter
MAC Output Limiter
31
Condition Code
Generation
MUX
C1
D1
A1
B1
Y1
Y0
X0
Data Registers
Data ALU Overview and Architecture
EXT:MSP:LSP
36-Bit Accumulator
16
15
Shifter
A0
B0
C0
D0
0
5-3