Variable Precision DSP Blocks User Guide: Agilex™ 5 FPGAs and SoCs

ID 813968
Date 3/13/2025
Public

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3.2.2.3. Sum of Two FP16 Multiplication with FP32 Addition Mode

This mode performs a summation of two half-precision multiplication, provide a 32-bit result, and add with a single-precision number:

fp32_result = (fp16_mult_top_a*fp16_mult_top_b) + (fp16_mult_bot_a*fp16_mult_bot_b) + fp32_adder_a

The following are exception flags supported in flushed and bfloat16 formats:
  • fp16_mult_top_invalid
  • fp16_mult_top_inexact
  • fp16_mult_top_overflow
  • fp16_mult_top_underflow
  • fp16_mult_bot_invalid
  • fp16_mult_bot_inexact
  • fp16_mult_bot_overflow
  • fp16_mult_bot_underflow
  • fp16_adder_invalid
  • fp16_adder_inexact
  • fp16_adder_overflow
  • fp16_adder_underflow
  • fp32_adder_invalid
  • fp32_adder_inexact
  • fp32_adder_overflow
  • fp32_adder_underflow
The following are exception flags supported in extended format:
  • fp16_mult_top_invalid
  • fp16_mult_top_inexact
  • fp16_mult_top_infinite
  • fp16_mult_top_zero
  • fp16_mult_bot_invalid
  • fp16_mult_bot_inexact
  • fp16_mult_bot_infinite
  • fp16_mult_bot_zero
  • fp16_adder_invalid
  • fp16_adder_inexact
  • fp16_adder_infinite
  • fp16_adder_zero
  • fp32_adder_invalid
  • fp32_adder_inexact
  • fp32_adder_overflow
  • fp32_adder_underflow
Figure 38. Sum of Two FP16 Multiplication with FP32 Addition Mode