65. TFA

65.1. Overview

TFA is a hardware trigonometric function accelerator used to improve math operation performance.

65.2. Supported Functions

  • INV(x)

  • SQRT(x)

  • SIN(x)

  • COS(x)

  • POW(2,x)

  • LOG2(x)

  • ATAN(x)

  • INVSQRT(x)

  • ATAN2(y,x)

  • CORDIC(x,y)

Note

ATAN2 and CORDIC functions are only supported on some SoCs. On other SoCs, selecting these functions will print a “not supported” message.

65.3. Hardware Configuration

No special hardware configuration required.

65.4. Toolchain Requirements

This example requires a DSP-enabled toolchain:

  • IDE: Segger Embedded Studio (or other IDEs with DSP toolchain support)

  • GCC Toolchain: Andes RISC-V toolchain (with DSP extension) or ZCC toolchain (with DSP extension)

Note

Standard GCC toolchains without DSP extensions cannot correctly compile and run this example.

65.5. Running the Program

The program enables FPU by default for optimal performance, with an option to disable FPU.

Run Example (FPU enabled):

*********************************************************************************
*                                                                               *
*                         TFA Example Menu                                      *
*                                                                               *
* 0 - INV TEST                                                                  *
* 1 - SQRT TEST                                                                 *
* 2 - SIN TEST                                                                  *
* 3 - COS TEST                                                                  *
* 4 - POW2 TEST                                                                 *
* 5 - LOG2 TEST                                                                 *
* 6 - ATAN TEST                                                                 *
* 7 - INVSQRT TEST                                                              *
* 8 - ANANPU2 TEST                                                              *
* 9 - CORDIC32 OPERATION                                                        *
* A - MIXED OPERATION                                                           *
*                                                                               *
*********************************************************************************

Menu 0–9 test 10 TFA functions, comparing result and cycle time against the library. Results:

0
tfa and math diff value:-0.000000, math calculation time:33 ticks, tfa calculation time:62 ticks.
1
tfa and math diff value:0.000000, math calculation time:363 ticks, tfa calculation time:63 ticks.
2
tfa and math diff value:0.000000, math calculation time:1755 ticks, tfa calculation time:63 ticks.
3
tfa and math diff value:0.000000, math calculation time:1826 ticks, tfa calculation time:63 ticks.
4
tfa and math diff value:0.000000, math calculation time:3031 ticks, tfa calculation time:63 ticks.
5
tfa and math diff value:-0.000000, math calculation time:2875 ticks, tfa calculation time:63 ticks.
6
tfa and math diff value:-0.000000, math calculation time:1959 ticks, tfa calculation time:180 ticks.
7
tfa and math diff value:-0.000000, math calculation time:552 ticks, tfa calculation time:63 ticks.
8
tfa and math diff value:0.000000, math calculation time:2108 ticks, tfa calculation time:150 ticks.
9
math angle value:6.981058, tfa angle value:6.980525, tfa and math angle diff value:-0.000533, math mode value:98.731964, tfa mode value:98.000000, tfa and math mode diff value:-0.731960, math calculation time:2901 ticks, tfa calculation time:93 ticks.

Menu option A performs a complex calculation, comparing its result and timing against the library function. Results:

A
tfa and math diff value:-0.000000, math calculation time:9088 ticks, tfa calculation time:290 ticks.