Re: [cc65] 16-bit writes on 65816

From: Scott Goldman <>
Date: 2009-01-07 00:34:05
Ah, I was under the impression that the 65816 was mostly backwards 
compatible (it can execute the same opcodes) but there must be some 
trickery there. I try to call my C function from asm but the runtime for 
comparing 16-bit values (tosicmp) seems to have issues as my for loop 
short circuits and never runs the code in the inner body:
  int i;
  for(i=0; i<512; i++) ...
I even made sure that before i jsr into my C function, I did:
sep     #$30

So that the registers would be in the traditional 8-bit mode.

Oh well, I guess I'll just do this project the old fashioned way...


Ullrich von Bassewitz wrote:
> On Tue, Jan 06, 2009 at 02:02:06PM +0100, Oliver Schmidt wrote:
>> Just in case there should be a momentum for a cc65 compiler port to the
>> 65816, I'd like to mention that would be willing to work on a ProDOS 16
>> (-API) based C-library for the Apple IIgs.
> A compiler port is quite some work. Changing the code generator is the
> smallest and easiest part. But all optimizations are done at the machine code
> level, so this has to be completely rewritten for the 65816. In addition, the
> complete runtime and C library is missing. 
> Regards
>         Uz
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Received on Wed Jan 7 00:34:11 2009

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