Altera Integer Arithmetic IP User Manual
Page 84
Table 8-1: ALTMULT_ACCUM Resource Utilization and Performance
Device family
Input data
width
Number of
multipliers
Logic Usage
18-bit DSP
f
MAX
(MHz)
(5)
Adaptive
Look-Up
Table
(ALUT)
Dedicated
Logic
Register
(DLR)
Adaptive
Logic
Module
(ALM)
Stratix III
16 ×16
1
0
0
0
4
481
16 ×16
2
0
0
0
4
481
Stratix IV
16 ×16
1
0
0
0
4
443
16 ×16
2
0
0
0
4
443
In the Stratix, Stratix GX, and Arria GX device series, the multiplier and the accumulator of the
ALTMULT_ACCUM megafunction are placed in the DSP block circuitry. For Stratix V devices, the
multiplier blocks and adder/accumulator block (mac_mult and mac_out) are combined into a single
multiplier accumulator (MAC) block. The DSP blocks use the 18-bit × 18-bit input multiplier to process
data with widths of up to 18 bits.
The registers and extra pipeline registers for the following signals are also placed inside the DSP block:
• Data input
• Signed or unsigned select
• Add or subtract select
• Synchronous load
• Products of multipliers
In the case of the output result, the first register is placed in the DSP block. The extra latency registers are
placed in logic elements outside the block.
Cyclone II and Cyclone III devices have embedded multiplier blocks. When the ALTMULT_ACCUM
megafunction is implemented in Cyclone II and Cyclone III devices, the multiplier is implemented in the
embedded multiplier blocks, while the accumulator is put in LEs. In Cyclone devices, both the multiplier
and accumulator are placed in LEs.
For more information about DSP blocks in any of the Stratix, Stratix GX, and Arria GX device series, refer
For more information about the embedded memory blocks in any of the Stratix, Stratix GX, and Arria GX
device series, refer to the TriMatrix Embedded Memory Blocks chapter of the respective handbooks on
the
.
For more information about embedded multiplier blocks in the Cyclone II and Cyclone III devices, refer
For more information about implementing multipliers using DSP and memory blocks in Altera FPGAs,
.
(5)
The performance of the megafunction is dependant on the value of the maximum allowable ceiling f
MAX
that the selected device can achieve. Therefore, results may vary from the numbers stated in this column.
UG-01063
2014.12.19
Resource Utilization and Performance
8-3
ALTMULT_ACCUM (Multiply-Accumulate)
Altera Corporation