I recall there is a way to do this, but I don't remember exactly how.
I am PRINTing continuous text to the screen using semicolons with each PRINT command. When the printing reaches the bottom of the screen, the screen data "jumps" upward several lines.
It creates a "jerky" scroll effect. I thought I could turn this feature with a POKE 658,1, but it does not seem to have any effect. Does anyone have any ideas?
In addition, there must be a location that tells the cursor how many spaces to move down with a down cursor command. If I could find this, it could be helpful. I am thinking location 213 - 244 could work in some way, but I haven't been able to figure it out.
How do I stop print scrolling?
Moderator: Moderators
Re: How do I stop print scrolling?
Cursor addressing is done using an index into a table of pointers, the row index is called TBLXJeff-20 wrote: In addition, there must be a location that tells the cursor how many spaces to move down with a down cursor command. If I could find this, it could be helpful. I am thinking location 213 - 244 could work in some way, but I haven't been able to figure it out.
https://eden.mose.org.uk/gitweb/?p=rom- ... =HEAD#l617
The table is built on boot from a table in KERNAL ROM, the stride is hard-coded at 22
https://eden.mose.org.uk/gitweb/?p=rom- ... EAD#l10452
Pressing Crsr-Dwn just increments the index.
https://eden.mose.org.uk/gitweb/?p=rom- ... HEAD#l9911
Re: How do I stop print scrolling?
Thanks, srowe! That's very useful information. I figured out a trick to avoid the issue in my specific application. It seems the screen "jumps up" about four rows when I print at the bottom. I thought there was a way to turn that off.
Re: How do I stop print scrolling?
Yes, you must make sure not to print the last character of the last line to avoid the scroll. There is some nifty PRINT-technique where you use cursor-left and insert in quote mode to push the final character to the last position, but it may be easier to just POKE to that screen destination.
Re: How do I stop print scrolling?
print a "home" character at the end of the line???
Re: How do I stop print scrolling?
or just dont use the bottom line...or use it to display score, etc without using the last positiontokra wrote:Yes, you must make sure not to print the last character of the last line to avoid the scroll. There is some nifty PRINT-technique where you use cursor-left and insert in quote mode to push the final character to the last position, but it may be easier to just POKE to that screen destination.