ARM Cortex-M3 and Cortex-M4 Processors Chapter21. DSP Applications 학부연수생 최문식

Contents DSP on a microcontroller Dot product example Cortex-M4 DSP instructions

DSP on a microcontroller Digital Signal Processing(DSP) Lower power consumption. Ease of integration. Lower overall system cost.

Dot product example

M3, the inner loop Takes 10 to 14 cycles M4, the inner loop Cortex-M3 M3, the inner loop Takes 10 to 14 cycles Cortex-M4 M4, the inner loop Takes 7 cycles

Cortex-M4 DSP instructions Registers

Data types

Fractional arithmetic

8-bit fractional values -> “q7_t” 16-bit fractional values -> “q15_t”

SIMD(Single Instruction Multiple Data)

Load and store instructions in CMSIS library 8-bit 16-bit

Arithmetic instructions SSAT – signed saturation

SMMUL – 32bit multiply returning 32 most significant bits

SMMLA – 32bit multiply with 32 most significant bit accumulate

Floating-point instructions