Re: [stella] Re: Help with efficient code

Subject: Re: [stella] Re: Help with efficient code
From: Eckhard_Stolberg@xxxxxxxxxxxxxxxxxxxxx (Eckhard Stolberg)
Date: Tue, 30 Sep 1997 16:52:07 +0200
>Whoops!  Forgot about jmp (abs,x) which I remembered as a 65816 opcode.
>Sorry... and thanks to Amos Bannister for the reminder (btw, the
>instruction works differently than his example.)

I couldn't find this addressing mode in any illegal instuction reference.
Are you sure it exists on the 6507? By calculating the opcode with one
of my references I got $40 for 'jmp (abs,x)', but this is the opcode for
'rti'. Since the 6507 doesn't have any interrupt support, does $40 work
as 'jmp (abs,x)' on the 6507? Or has this something to do with the I-flag
not being set?

Thanks, Eckhard Stolberg

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