PDSP1601 Mitel Networks Corporation, PDSP1601 Datasheet - Page 7

• Manufacturer Part Number: PDSP1601
• Description: ALU and Barrel Shifter
• Manufacturer: Mitel Networks Corporation

Priority Encoder
value (instructions:- NRMXX, NRMR1, MRMRZ), then within
one 100ns cycle or two 50ns cycles for the PDSP1601A (one
200ns or two 100ns cycles for the PDSP1601), the shift
circuitry will:
If the priority encoder is selected as the source of the shift
16
4
SV3
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
Table 3 Barrel shifter codes
SV2
MUX
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
SV1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
SV0
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
10 places
11 places
12 places
13 places
14 places
15 places
2 places
3 places
4 places
5 places
6 places
7 places
8 places
9 places
No shift
1 place
Shift
PRIORITY ENCODER
Fig.3 Shift control block
MUX
R1
(1)
place the 4 bit value in either of the R1 or R2 registers and
output the value on the SV port (if enabled by SVOE).
(2)
Priority Encoder such that the output from the Barrel Shifter is
a normalised value.
SV Input
then the input to the Barrel Shifter is shifted by the value stored
in the internal SV register.
SVOE
SVOE
SVOE
the IS0-3 instruction. If the user does not wish to use the
normalise instructions, then the SV port mat be forced to be
input only by typing SVOE control high. In this mode the SV
port may be considered an extension of the instruction inputs.
R1 and R2 Registers
Encoder (NRMR1 and NRMR2) or from the SV input (LR1SV,
LR2SV).
Shifter will pass its input to the output unshifted.
SVOE
SVOE
If the SV port is selected as the source of the shift value,
The SV port acts as an input or an output depending upon
The R1 and R2 registers may be loaded from the Priority
Whilst the latter two instructions are executing, the Barrel
Priority encode the 16 bit input to the Barrel Shifter and
Shift the 16 bit input by the amount indicated by the
MUX
R2
INSTRUCTION
DECODE
PDSP1601/PDSP1601A
4
4
IS0-3
SVOE
SV
7