Intel® Stratix® 10 Variable Precision DSP Blocks User Guide

ID 683832
Date 8/13/2021
Public
Document Table of Contents

3.1.4. 18 × 19 Multiplication Summed with 36-Bit Input Mode

Intel® Stratix® 10 variable precision DSP blocks support one 18 × 19 multiplication summed to a 36-bit input.

The 18 × 19 multiplication summed with 36-bit input mode uses the equations:
  • resulta = (ax * ay) + by to sum the 18 x 19 multiplication with 36-bit input.
  • resulta = (ax * ay) - by to subtract the 18 x 19 multiplication with 36-bit input.

Use the upper multiplier to provide the input for an 18 × 19 multiplication, while the bottom multiplier is bypassed. The by[17..0] and bx[35..18] signals are concatenated to produce a 36-bit input.

Use the SUB dynamic control signal to control the adder to perform addition or subtraction operation.

Figure 11. One 18 x 19 Multiplication Summed with 36-Bit Input Mode for Intel® Stratix® 10 Devices

In this figure, the variable is defined as follows:

  • n = 19 for 18 × 19 signed operands
  • n = 18 for 18 × 18 unsigned operands