[cc65] Re: Target BBC - info only

> Message-ID: <4252A544.3040103@kollus.de>
 
Kolja_Nikolaus_Sträter <k@kollus.de> wrote:
> Just wanted to say that I've done a bit of initial delving into the
> BBC-target problem. I needed some in- and output, so I got a couple of
> routines working using OSWORD calls. Somebody must have done this
> already, but I wanted to do this myself to get to know Uz's code a bit.
> Anyway, reinventing a few small wheels can't do any harm :-)
 
Hi Kol.
 
Can I suggest you look at www.mdfs.net/System/C/6502/Small-C/v072
where I've been working on 'ANSI-ising' A.J.Travis' Small-C for
the BBC. Specifically, browse through includes/os.h and
includes/kernel.h. os.h functions modify the passed variables and
return an 'ok/not ok' flag. The kernel.h functions return their
return value.
 
source/sys.s has the 6502 source of many of the core library
functions.
 
The OS functions should be named 'os_*' as listed in os.h. I need
to add a few others:
 
os_escape() - check Escape flag:
   LDA &FF, AND #&80, return value
os_error() - generate an error:
   copy error number and string to &0100, jump to cause error
os_report() - return pointer to last error:
   Read &FD/&FE, return value.
 
one of the signal() states should be 'error' to do a signal trap
equivalent of ON ERROR.
 
...and the equivalents for kernel.h. I need to think a bit about
the parameters, etc., ultimately, you should be able to do
something like: fprint("%s",_kernel_report());
 
Also, somewhere, I've got some relocation code so that a 'C'
program can be compiled to load in high memory (&8000-length) and
then it relocates itself to the current PAGE, clears screen to
reset high memory and RTSes to PAGE to execute.
 
And some sort of directive to specify actual load/exec addresses.
It would be theortically possible to compile a 'C' program as a
transient program loaded to the transient command area at
&0900-&0AFF.
 
main() { os_vdu(7); }
 
/should/ compile to LDA #7:JSR &FFEE:LDA #0:RTS if appropriate
switches are set. Maybe even to: LDA #7:JMP &FFEE :)
 
I'm going to be hugely busy for the next 30 days, but I'll try to
keep in touch.
 
-- 
J.G.Harston - jgh@arcade.demon.co.uk - mdfs.net/User/JGH
Prospective Parliamentary Candidate for Sheffield Brightside
BBC BASIC for Windows and Internationalisation
  See http://mdfs.net/Software/BBCBasic/Windows/ProgTips
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