See the SmartGen
Cores Reference Guide for additional information on this core.
Parameterized word length
Optional carry-in and carry-out signals
Multiple gate-level implementations (speed/area tradeoffs)
Behavioral simulation model in VHDL and Verilog
ACT 1, ACT 2, ACT 3, 3200DX, MX, SX, SX-A, eX, 500K, PA, Axcelerator, ProASIC3/E, Fusion
For the Sklansky Adder, you can clear the Automatic Max. Fanout check box and specify a value for max fanout. This makes SmartGen perform logic replication on high-fanout nets so that the maximum fanout for all the nets in the design is not more than the value specified. If it is set to automatic, SmartGen automatically makes the decision for logic replication based on the size of the design.
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Port Description |
|
Port Name |
Size |
Type |
Req/Opt |
Function |
|
DataA |
WIDTH |
Input |
Req. |
Input Data |
|
DataB |
WIDTH |
Input |
Req. |
Input Data |
|
Cin |
1 |
Input |
Opt. |
Carry-in |
|
Sum |
WIDTH |
Output |
Req. |
Sum |
|
Cout |
1 |
Output |
Opt. |
Carry-out |
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Parameter Description |
|
Parameter |
Family |
Value |
Function |
|
WIDTHA |
500K, PA |
2-128 |
Word length of DataA, DataB and Sum |
|
Axcelerator |
2-156 |
||
|
All others |
2-32 |
||
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MAXFANOUT |
500K, PA |
0 |
Automatic choice |
|
2-16 |
Manual setting of Max. Fanout | ||
|
CI_POLARITY |
ALL |
0 1 2 |
Carry-in polarity (active low, active high, and not used) |
|
CO_POLARITY |
ALL |
0 1 2 |
Carry-out polarity (active low, active high, and not used) |
|
A. The Brent-Kung Adder extends the ranges from 32 to 128 bit for SX, SX-A and from 20 to 128 bit for 500K. |
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Implementation Parameters |
|
Parameter |
Family |
Value |
Description |
|
LPMTYPE |
All |
LPM_ADD_SUB |
Adder category |
|
LPM_HINT |
500K, PA |
SKADD |
Sklansky model |
|
FBKADD |
Fast Brent-Kung model | ||
|
BKADD |
Compact Brent-Kung model | ||
|
ALL |
FADDA |
Very fast carry select model | |
|
MFADDA |
Fast carry select model | ||
|
RIPADD |
Ripple carry model | ||
|
LPMTYPE |
Axcelerator |
LPM_FC_ADD_SUB |
Fast carry chain Adder category |
|
LPM_HINT |
FC_FADD |
Fast carry chain carry select model | |
|
FC_RIPADD |
Fast carry chain ripple carry model |
A. FADD and MFADD are NOT recommended for Flash devices.
|
Functional Description |
|
DataA |
DataB |
Sum |
CoutA |
|
m[width-1 : 0] |
n[width-1 : 0] |
(m + n + Cin )[width-1 : 0] |
(m + n + Cin)[width] |
|
A. Cin and Cout are assumed to be active high. |