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Calling an Assembly Functon From C (RVMDK)

Eric Severson

Hello,

I am struggling to do something that should be very simple: call an assembly function from a C function. Can anyone give me some pointers or an example of how to do this?

I am using uVision 3 with Realview MDK C compiler.

All of the documentation that I am finding points me to use inline assembly commands. However, this won't work, as I need the assembly code to modify the stack pointer.

Here is what I would like the code to:

void ChangeRegion (void)
{
     asm_adjust_sp(0x78000);  //call assembly to change the stack pointer
}

//asm_adjust_spi(Ulong ulAddress)
//1. change stack pointer to 0x4000F000
//2. branch to a the address contained by ulAddress

Any help that you can provide would be greatly appreciated.

Thanks!

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  • 0 in reply to Eric Severson

    The reason for this is that their boot loader does not appear to reset the stack pointer

    you don't need to mess around with the stack to fix this. when passing control from the bootloader to the application, change the processor to SVC mode - or more specifically - make the 'jump to application' function a SWI function. that will allow the addresses of the stacks to be set in the application's startup file code.

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  • 0 in reply to Eric Severson

    The reason for this is that their boot loader does not appear to reset the stack pointer

    you don't need to mess around with the stack to fix this. when passing control from the bootloader to the application, change the processor to SVC mode - or more specifically - make the 'jump to application' function a SWI function. that will allow the addresses of the stacks to be set in the application's startup file code.

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