Re: Hires - to - Lores ... Yikes

["Bill Garber" <willy46pa@comcast DOT net>]

"Bender MX" <no@morespam.com> wrote in message
news:Mq0Mc.47557$2i3.27799@clgrps12...
: Hi All,
:
: LOL, I was messing around with converting Lo-Res into Hires and
for
: kicks, decided to try it the other way around ...
:
: Here's the Routine, starting at 768 ($300)
:
: 300- A2 00                LDX  #$00
: 302- BD 00 20           LDA $2000,X
: 305- 9D 00 04           STA $0400,X
: 308- E8                      INX
: 309- D0 F7                BNE $0302
: 30B- EE 04 03           INC $0304
: 30E- EE 07 03           INC $0307
: 311- AD 07 03          LDA $0307
: 314- C9 08               CMP #$08
: 316- D0 E8               BNE $0300
: 318- 60                     RTS
:
: What it will do is only scan from $2000 to $2400 (hires pg 1)
: and move it into $0400 - $0800 (lores pg 1) memory locations
: and it trashes the memory locations $0304 and $0307
: after - or more correctly, it never returns them to the
: original value, so don't Call 768 (or 300G) two times
: in a row without re-poking or resetting $0304 to $20
: and $0307 to $40 as these two locations are what set
: it to scan page 1 HGR and put it into page 1 gr/text

Restore those locations at the end before you RTS.  :o)

Bill @ GarberStreet Enterprizez };-)
Web Site - http://garberstreet.netfirms.com
Email - willy46pa @ comcast DOT net
Change DOT to a dot to contact me



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