Hello everyone. I have two questions about linker. Actually I'm not sure, it's about linker, but I guess it's about it.
Target - Cortex M4F IDE - Keil uVision 5.15 Language - assembler Toolchain - Keil
So, I have a very small project written in assembler. I need assembler for students to study microcontrollers programming. It contains three files: "startup.s", "my_prog.s" (smth like "main.c") and "CPU_12.lib" (this one contains two mulitplication functions).
First question: In main program, one function from the "*.lib"-file is called. But during debug session it can be seen, that both functions were placed in memory. How can I avoid this? If i have a lib with 1000 function, and only use 1 of them - all lib will be linked to my project? I've tried to use "--feedback" for linker and compiler, but it didn't help.
Second question intro: if i have my program in flash memory and variables in RAM, i have to initialize them with values (smth like "int x = 1;" in C). In C-like projects it's done automatically - necessary functions are linked before "main()" inside a generated "__main()"-function. I've tried to find the way linker does initialization, but i couldn't. Usually algorithm is like this: from address A in flash, copy DATA_SIZE bytes to address B in RAM. So we need at least three variables, generated by linker - A, B and DATA_SIZE. Looks like they are in some auto-generated structure Region$$Table$$Base - first three words. I found this struct in map-file and examined it, though i couldn't find any info on this struct in the internet. So the question is - how can I do this initialization in assembler project? Looks like i have to reserve space in RAM with "SPACE" directive, and declare values with "DCD" directive. But how can I know where to copy this values during runtime? Where can i get analogues for "A", "B" and "DATA_SIZE" values?
I will appreciate any help in this question. Here's the project. It was created in uVision 5.15. Sorry for comments in Russian. www.yadi.sk/.../3RDF-OtY3CgoqD
Thanks everyone.
Well if you want Keil code to fix it up, then call __main and create a "main" entry point to your own code.
Alternatively do it manually, with LDR/STR instructions, it will reinforce the realization that RAM isn't actually initialized when the CPU starts.
I would prefer the visibility of an all-assembler solution, i.e. real bare-bone programming.
Use own labels or let the linker help.