> Yes, since I'm writing both of them.  But even if not, the
> restrictions
> are few and easily dealt with.

By you, yes. I am not stating that your bootloader is not usefull, but
the other approach has its merits too. The novice user of a basic
compiler is not likely to know what a start vector is, even if his
compiler allows him to change the vector.

> Using a different start vector requires only
> changing a
> single number in a single file.

There is more in this world that just assembler.

> So I guess you're bootloader relocates the first 4 words to somewhere
> else?  That sounds difficult to do in the completely general
> case.  Do you
> assume that first word is a GOTO, or set PCLATH then GOTO?
> Since you are
> aiming this as beginners, what if they do just GOTO and
> assume PCLATH is 0
> (or didn't even think about PCLATH)?  In that case you can't
> just relocate
> the 4 words into the bootloader somewhere.  The GOTO would
> have to be in
> the first page.

The details can be found on the WLoader page (my site) and in the ZPL
article on the Circuit Cellar site. For a 14-bit core (16 bit is much
more complicated) the idea is
- I grab the first 3 instructions (set pclath, goto)
- these 3 instrcutions are relocated else where
- after these 3 relocated instructions is a jump to 0x03
- before I jump to these 3 instructions I restore the power-on
situation, including pclath==0

> The linker could stick a short routine in locations 2 and 3

That breaks my cleverness. This specific case is explicitly mentioned in
the WLoader page. But in that case the user is back to a more or less
the same requirement as for your bootloader: specify a differenr ORG
(0RG 2 would do). I have indeed seen this in one case.

> This is only
> a slight modification of the linker control file, but it
> still has to be
> done somehow.

Again, think of non-assembler programmers. Might be difficult for you to
imagine, but they do exist ;)

Wouter van Ooijen

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