Can I port a library compliled for Cortex M3 onto a cortex M4?

Question

I have received a library which is pre-compiled for cortex M3. Can I cross-compile it for cortex M4 and port it without access to the original source code?

Answer 1

If this library is in the form of ".a" file, then there is no way to "recompile" it, as you have no access to source code.

But if this code is NOT accessing any peripherals which are different on the two chips you want to use, then there's no need to recompile anything. ARM Cortex-M4 is almost identical to ARM Cortex-M3 - the former may have a FPU and has some DSP instructions, but at the same time supports all of the Thumb-2 instructions from ARM Cortex-M3.

So this all depends on what this library is actually doing...

Answer 2

ARM cortex M4 and Cortex M3 follows the same architecture ARMV7M so the instruction set is almost the same what work in cortex M3 must work in cortex M4 however you have to take care of the address of the peripherals between the two embedded hardware if there is a change so accessing some changed base address of peripheral will cause problems.

But take this as fundamental equation concerning ARM processor : Cortex M4= CortexM3 + DSP