A86: Re: Screen Offset Routine

A86: Re: Screen Offset Routine

• To: <assembly-86@lists.ticalc.org>
• Subject: A86: Re: Screen Offset Routine
• From: "David Phillips" <david@acz.org>
• Date: Thu, 1 Apr 1999 21:58:12 -0600
• Delivered-To: assembly-86-outgoing@towerguard.unix.edu.sollentuna.se
• Delivered-To: assembly-86@lists.ticalc.org
• References: <19990401.191326.2423.0.Ziggy2282@juno.com>
• Reply-To: assembly-86@lists.ticalc.org

Hehe...maybe the 82/83 display controller _does_ have a nice feature.  Below
is the routine from the OS-82 version of FFX4.  As you can see, it won't
work on the 85/86:

shake:
 ld      b,3
shakeloop:
 push    bc
 ld      a,42h
 out     (10h),a
 CALL_(DELAY4)
 ld      a,40h
 out     (10h),a
 CALL_(DELAY4)
 pop     bc
 djnz    shakeloop
 RET



>
> How can you write a routine to "shake" the screen, by changing the
> offset?  I'm trying to make it so that this box I have defined around the
> edges of the screen appears to shake up and down.  I did not define the
> very bottom pixel row and the busy indicator row, to allow for this.  So,
> how do I shift the box to the lower row then back up, to make it look
> like the screen shakes.  I've seen this effect on FFX4 for the 82/83.
> Thanx,

• A86: Re: Screen Offset Routine
• From: Nicolas P Zagorin <ziggy2282@juno.com>

• A86: Screen Offset Routine
• From: Nicolas P Zagorin <ziggy2282@juno.com>

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