Static memory map analysis
memap is a simple utility that displays static memory information required by Arm Mbed applications. This information is produced by analyzing the memory map file previously generated by your toolchain.
Note: This tool shows static RAM usage and the total size of allocated heap and stack space defined at compile time, not the actual heap and stack usage (which may be different depending on your application).
memap is automatically invoked after an Mbed build finishes successfully. It's also possible to manually run the program with different command-line options, for example:
$> python memap.py usage: memap.py [-h] -t TOOLCHAIN [-o OUTPUT] [-e EXPORT] [-v] file Memory Map File Analyser for ARM mbed version 0.3.11 positional arguments: file memory map file optional arguments: -h, --help show this help message and exit -t TOOLCHAIN, --toolchain TOOLCHAIN select a toolchain used to build the memory map file (ARM, ARMC6, GCC_ARM, IAR) -o OUTPUT, --output OUTPUT output file name -e EXPORT, --export EXPORT export format (examples: 'json', 'csv-ci', 'table': default) -v, --version show program's version number and exit
$> python memap.py GCC_ARM\myprog3.map -t GCC_ARM +----------------------------+-------+-------+------+ | Module | .text | .data | .bss | +----------------------------+-------+-------+------+ | Fill | 170 | 0 | 2294 | | Misc | 36282 | 2220 | 2152 | | core/hal | 15396 | 16 | 568 | | core/rtos | 6751 | 24 | 2662 | | features/FEATURE_IPV4 | 96 | 0 | 48 | | frameworks/greentea-client | 912 | 28 | 44 | | frameworks/utest | 3079 | 0 | 732 | | Subtotals | 62686 | 2288 | 8500 | +----------------------------+-------+-------+------+ Allocated Heap: 65540 bytes Allocated Stack: 32768 bytes Total Static RAM memory (data + bss): 10788 bytes Total RAM memory (data + bss + heap + stack): 109096 bytes Total Flash memory (text + data + misc): 66014 bytes
Information on memory sections
The table above showed multiple memory sections.
.text: is where the code application and constants are located in Flash.
.data: nonzero initialized variables; allocated in both RAM and Flash memory (variables are copied from Flash to RAM at runtime).
.bss: uninitialized data allocated in RAM, or variables initialized to zero.
Heap: dynamic allocations in the Heap area in RAM (for example, used by
malloc). The maximum size value may be defined at build time.
Stack: dynamic allocations in the Stack area in RAM (for example, used to store local data, temporary data when branching to a subroutine or context switch information). The maximum size value may be defined at build time.
There are other entries that require a bit of clarification:
Fill: represents the bytes in multiple sections (RAM and Flash) that the toolchain has filled with zeros because it requires subsequent data or code to be aligned appropriately in memory.
Misc: usually represents helper libraries introduced by the toolchain (like
libc), but can also represent modules that are not part of Mbed.
We have tested memap on Windows 7, Linux and Mac OS X. The
GCC_ARM (GNU Arm Embedded Toolchain), Arm Compiler 5, Arm Compiler 6 and IAR toolchains generate memory map files.
Known issues and new features
This utility is considered "alpha" quality at the moment. The information generated by this utility may not be fully accurate and may vary from one toolchain to another.
If you are experiencing problems, or would like additional features, please raise a ticket on GitHub and use
[memap] in the title.