CODEWITHSUNDEEP
clinkerembeddedcortex-m
hiak
hiak

Reputation: 93

LPC1788 - Bootloader and shared library

I'm developing an embedded software for my custom board (LPC1788). My objective is to improve skill and experience regarding C programming for embedded systems.

I have implemented a USB Bootloader that launches the user application if it exists. Otherwise it is used to easily load the application through USB. My USB bootloader uses a static library board.a, and so does the user application.

Is there any trick how to reference board.a, which was linked into the binary of the bootloader, from the user application?

In other words, I want to optimize flash memory space by putting in the board.a code and data just once.

NB: I use LPCXpresso (NXP MCU Tools/GNU Make Builder) it invoke arm-none-eabi-gcc (GNU ARM Embedded Toolchain)

Upvotes: 3

Views: 646

Answers (1)

old_timer
old_timer

Reputation: 71536

Just like using shared libraries on an operating system. your system design can be such that when the bootloader branches to the application it could for example use one of the registers (r0 for example) to contain the address to the "shared" library, or it could contain a pointer to an array of pointers that are the addresses to the individual functions within board.a that you want to share. Functions are nothing more than addresses from a linking/using perspective anyway so it is a matter of matching up function pointers in the application with the already in place functions in the address space (flash I assume). This is all that shared libraries do they just have libraries and stubs to help it be invisible to your applications that run on those operating systems.

Upvotes: 2

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