STM32F051C8

Perhaps you could just look at the startup_stm32f0xx.s for inspiration?

Calling C functions

        IMPORT  SystemInit

                 LDR     R0, =SystemInit
                 BLX     R0

void SystemInit(void)
{
 // ..
}

Calling ASM functions

foo PROC
    EXPORT foo

    bx lr

    ENDP ; foo

extern void foo(void);

foo();

Perhaps you could just look at the startup_stm32f0xx.s for inspiration?

Calling C functions

        IMPORT  SystemInit

                 LDR     R0, =SystemInit
                 BLX     R0

void SystemInit(void)
{
 // ..
}

Calling ASM functions

foo PROC
    EXPORT foo

    bx lr

    ENDP ; foo

extern void foo(void);

foo();

Perhaps you could just look at the startup_stm32f0xx.s for inspiration?

That's the very thing I did many moons ago when I started this embedded career. If only the Keil forum were available back then, I could have saved a shedload of time and just asked here for the information.

A metric or imperial shedload?

I just wish I could have found a good vulcan embedded engineer, sharing his knowledge would have been so much easier.

Unfortunately relying on others for knowledge tends to significantly reduce the value of potential hires. There has to be more material available these days, and it's far easier to search and locate.