Re: [cc65] c64 question

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From: groepaz (groepaz_at_gmx.net)
Date: 2001-03-06 12:08:52


Hello Arvid,

Tuesday, March 06, 2001, 12:17:25 PM, you wrote:

AN> Hello,

AN> I'm sorry to a post computer-specific question here, but you guys are 
AN> my last hope.. ;)

AN> What I'm trying to do is to scroll the lines 100 through 150 by using a 
AN> raster-interrupt (two actually). But I can't get it to work.


i tried that aswell (using C code in an interupt handler) and came to
the conclusion that it's not possible in a reasonable manner with
cc65...

i guess the problem is that if an irq occurs during the execution of
compiled c code, you should not only save the current value of A/X/Y
registers and cpu-stack pointer, but possibly also some more
(zeropage..?!) memory locations that are used by the runtime library
(the software stackpointer for eg).... you may also have to setup a second
software stack that is used in irq only to prevent curruption of the
'normal' stack....

whatever is the solution to that one, i want to know it aswell ;=)

if there's really a 'clean' way to achieve that kinda stuff, i'll
contribute some library routines to work with irq's and nmi's (i made
that kinda stuff already actually, just it freaks out for the reasons
i mentioned above)

so, is there a _detailed_ list about which zeropage and other memory
location are used by the runtime-library and what they are actually
used for ?! (that kinda list would be very useful for some other
purposes aswell btw ;D)

-- 
Best regards,
 groepaz                            mailto:groepaz_at_gmx.net


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