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Device Performance Optimization
MPC5644A Microcontroller Reference Manual, Rev. 6
Freescale Semiconductor
125
Figure 6-4. Influence of compiler settings on application performance and code size
NOTE
Data measured using Dhrystone version 2.1 run on a Power Architecture
based powertrain device that uses a standard commercial compiler.
The compiler optimizations do not necessarily have to be applied to the entire application. Analysis of an
application can identify time critical functions that may subsequently be targeted for performance
optimization, without incurring the impact of optimizing the entire application.
There are several other aspects of the compiler and linker that should be considered. In particular, the use
of Small Data Areas (SDAs, sometimes referred to as Special Data Areas) can make a significant
performance improvement. Refer to compiler documentation for usage guidelines on Small Data Areas.
6.4.2
Signal processing extension
To further optimize time critical functions, the Signal Processing Extension Auxiliary Processing Unit
(SPE-APU) may be used. The SPE-APU provides a set of Single Instruction Multiple Data (SIMD)
instructions. These SIMD instructions typically involve performing the same operation on multiple data
elements stored within a single 64-bit register. Through the implementation of SIMD instructions,
including vector multiply and accumulate (MAC) instructions, the SPE APU provides Digital Signal
Processing (DSP) functionality. This can be used to accelerate signal processing routines, such as Finite
Impulse Response (FIR), Infinite Impulse Response (IIR) and Discrete Fourier Transforms (DFT). A more
general benefit of the SPE instruction set is the ability to load/store 64-bits of data in single instruction.
Thus highly load/store intensive functions make good candidates for SPE optimization.
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Performance vs. Code Size
Normali
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Normalized Code Size
Size optimized
Trade-off
Speed optimized
Summary of Contents for MPC5644A
Page 2: ...MPC5644A Microcontroller Reference Manual Rev 6 2 Freescale Semiconductor...
Page 24: ...MPC5644A Microcontroller Reference Manual Rev 6 24 Freescale Semiconductor...
Page 26: ...MPC5644A Microcontroller Reference Manual Rev 6 26 Freescale Semiconductor...
Page 52: ...Introduction MPC5644A Microcontroller Reference Manual Rev 6 52 Freescale Semiconductor...
Page 56: ...Memory Map MPC5644A Microcontroller Reference Manual Rev 6 56 Freescale Semiconductor...
Page 1228: ...Decimation Filter MPC5644A Microcontroller Reference Manual Rev 6 1228 Freescale Semiconductor...
Page 1440: ...FlexCAN Module MPC5644A Microcontroller Reference Manual Rev 6 1440 Freescale Semiconductor...