EP4SE360F35I4 Datasheet, PDF (99/432 Pages) Altera Corporation – This section provides a complete overview of all features relating to the Stratix IV device family, which is the most architecturlly advanced

Chapter 4: DSP Blocks in Stratix IV Devices
Stratix IV Operational Mode Descriptions
4–19
36-Bit Multiplier
You can efficiently construct a 36 × 36 multiplier using four 18 × 18 multipliers. This
simplification fits conveniently into one half DSP block and is implemented in the
DSP block automatically by selecting 36 × 36 mode. Stratix IV devices can have up to
two 36-bit multipliers per DSP block (one 36-bit multiplier per half DSP block). The
36-bit multiplier is also under the independent multiplier mode but uses the entire
half DSP block, including the dedicated hardware logic after the pipeline registers to
implement the 36 × 36 bit multiplication operation, as shown in Figure 4–11.
The 36-bit multiplier is useful for applications requiring more than 18-bit precision;
for example, for the mantissa multiplication portion of single precision and extended
single precision floating-point arithmetic applications.
Figure 4–11. 36-Bit Independent Multiplier Mode Shown for a Half DSP Block
clock[3..0]
ena[3..0]
aclr[3..0]
signa
signb
dataa_0[35..18]
datab_0[35..18]
+
dataa_0[17..0]
datab_0[35..18]
dataa_0[35..18]
datab_0[17..0]
+
dataa_0[17..0]
datab_0[17..0]
Half-DSP Block
72
+
result[ ]
February 2011 Altera Corporation
Stratix IV Device Handbook
Volume 1