AN720 データシートの表示（PDF） - Silicon Laboratories

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AN720

PRECISION32 OPTIMIZATIONCONSIDERATIONS FOR CODESIZE ANDSPEED

Silicon Laboratories 

AN720

6. ARM/Keil µVision

This section discusses ways to optimize projects using the Keil or ARM toolchain in the µVision IDE. The Keil

µVision tools used for the code size and execution speed testing discussed in this document are version

v4.1.0.894.

6.1. Reading the Map File

The map file is an output of the linker that shows the size of each function and variable and their positions in

memory. This map file is located in the build files for a project. In addition to the functions, the map file includes

information on variables and other symbols, including unused functions that are removed.

Figure 9 shows an excerpt from the sim3u1xx_Blinky map file from the Keil toolchain. The functions are listed with

a base address and size. In this case, the my_rtc_alarm0_handler is 50 bytes located at address 0x0000_03A5.

Figure 9. sim3u1xx_Blinky µVision Map File Example

6.2. Determining a Project’s Code Size

The Keil µVision IDE automatically displays the code size information at the end of a successful build. After

building the si32HAL 1.0.1 sim3u1xx_Blinky example, the IDE outputs:

Program Size: Code=1968 RO-data=296 RW-data=24 ZI-data=1536

".\build\BlinkyApp.axf" - 0 Error(s), 0 Warning(s).

The areas of memory are:

Code: all program code in decimal

RO-data: read-only data located in flash in decimal

RW-data: read-write uninitialized data located in RAM in decimal

ZI-data: zero-initialized data located in RAM in decimal

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