Input Registers; Multiplier Stage - Altera Cyclone IV Device Handbook

Chapter 4: Embedded Multipliers in Cyclone IV Devices
Architecture
Figure 4–2
Figure 4–2. Multiplier Block Architecture

Input Registers

You can send each multiplier input signal into an input register or directly into the
multiplier in 9- or 18-bit sections, depending on the operational mode of the
multiplier. You can send each multiplier input signal through a register independently
of other input signals. For example, you can send the multiplier Data A signal through
a register and send the Data B signal directly to the multiplier.
The following control signals are available for each input register in the embedded
multiplier:
■ clock
clock enable
■
■ asynchronous clear
All input and output registers in a single embedded multiplier are fed by the same
clock, clock enable, and asynchronous clear signals.

Multiplier Stage

The multiplier stage of an embedded multiplier block supports 9 × 9 or 18 × 18
multipliers, as well as other multipliers between these configurations. Depending on
the data width or operational mode of the multiplier, a single embedded multiplier
can perform one or two multiplications in parallel. For multiplier information, refer to
"Operational Modes" on page
Each multiplier operand is a unique signed or unsigned number. The signa and signb
signals control an input of a multiplier and determine if the value is signed or
unsigned. If the signa signal is high, the Data A operand is a signed number. If the
signa signal is low, the Data A operand is an unsigned number.
February 2010 Altera Corporation
shows the multiplier block architecture.
signa
signb
aclr
clock
ena
Data A
D Q
ENA
CLRN
Data B
D Q
ENA
CLRN
4–4.
D Q
ENA
CLRN
Output
Input Register
Register
Embedded Multiplier Block
4–3
Data Out
Cyclone IV Device Handbook,
Volume 1