Re: Startup code

In article <11c4uoqp2qdc8f5@xxxxxxxxxxxxxxxxxx>, Meindert Sprang
<mhsprang@xxxxxxxxxxxxxxxxxxx> writes
>"Jet Morgan" <jm@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
>news:d9tsta$po7$1@xxxxxxxxxxxxxxxxxxxxxxx
>>
>> That is still startup code, even if written in C.
>
>In my opinion, startup code is code executed from the reset of the CPU,
>until the call to main().
>So any function you call from main() to setup up further things, no matter
>how low level and essential they are, is not called startup code.

I agree. However as many don't ever see the start up ASM they forget it
is there and refer to the initial C functions as set up code.

>> The compiler vendor will not typically know how the processor
>> is connected to the other devices, such as memory bus widths,
>> clock timings etc. That's why YOU (the designer) has to write it.
>
>If need be, yes.

In this case it is usually changing values a template start up file. It
is VERY rare that anyone does more than modify the file that comes with
the compiler.

Does anyone have an example where you have to write the whole start-up
file yourself?

>
>> There seems to be this perception that startup code is specifically
>> assembler. It *could* be written that way but I've always
>> written my startup code in a combination of C and assembler.
>
>Again, all startup codes I have seen so far, were written in assembler.

The have to be as the start up code gets you to the start of the C
program. After that it is application code?

>Probably because at startup time, there is no environment set up yet to run
>compiled C code at all.

That is why it is called start up code. (and has to be written in
assembler)

> But this only holds true with "my" definition of
>startup code, where the call to main() is not executed yet.
>
>Meindert

Well in my experience I would have to agree with you.


--
\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
\/\/\/\/\ Chris Hills Staffs England /\/\/\/\/
/\/\/ chris@xxxxxxxxxxxx www.phaedsys.org \/\/\
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