UM0585

STM32F10x DSP library benchmark

Doc ID 14988 Rev 2

19/25

6

STM32F10x DSP library benchmark

This section provides the STM32F10x DSP library benchmark results, which are computed

using the IAR EWARM 5.20 toolchain, with high-speed optimization.

6.1

Function code footprint

6.2

Function execution time

6.2.1

PID controller

Analysis of the PID timing shows that assembly code is not as fast as C code. The compiler

is more efficient in accessing variables than manual optimization (offset computation and

data placement in literal pool).

Table 11.

STM32F10x DSP library functions code footprint

Function name

Code size (bytes)

DoPID

52

DoFullPID

58

PID_stm32

72

cr4_fft_64_stm32

1.

FFT code size was computed with FFT coefficients table stored in Flash memory. If the FFT coefficients

are stored in SRAM, the code size of the three FFT functions is equal to 480 bytes.

cr4_fft_256_stm32

1486(1)

cr4_fft_1024_stm32

4560(1)

fir_16by16_stm32

162

iiarma_stm32

156

iir_biquad_stm32

294

Table 12.

PID controller, error computed outside the routine

PID

24 MHz

0 wait state

48 MHz

1 wait state

72 MHz

2 wait states

cycle count

time

cycle count

time

cycle count

time

ASM function

45

1.87 µs

51

1.06 µs

59

0.819 µs

C function

47

1.96 µs

50

1.04 µs

54

0.75 µs