Intel® Stratix® 10 Variable Precision DSP Blocks User Guide

ID 683832
Date 8/13/2021
Document Table of Contents Multiply-Add or Multiply-Subtract Mode

This mode performs floating-point multiplication followed by floating-point addition or floating-point subtraction. The chainin parameter allows you to enable a multiple-chain mode.

Table 14.  Equations Applied to Multiply-Add or Multiply-Subtract Mode
Chainin Parameter Multiply-Add Mode Multiply-Subtract Mode
Disable result = (ay*az) + ax result = (ay*az) - ax
Enable result = (ay*az) + chainin result = (ay*az) - chainin
The floating-point multiply-adder or multiply-subtract mode supports the following exception flags:
  • mult_invalid
  • mult_inexact
  • mult_overflow
  • mult_underflow
  • adder_invalid
  • adder_inexact
  • adder_overflow
  • adder_underflow
Figure 20. Multiply-Add or Multiply-Subtract Mode for Intel® Stratix® 10 Devices