DEF SEG ADDRESSES
DEF SEG ADDRESSES
(OP)
I was wondering what the DEF SEG = &HFFA6 is pointing to? And also could you tell me more useful memory addresses. Any would be fine. THX 
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RE: DEF SEG ADDRESSES
Text mode screen
for loading screen image (text)
def seg &HA000
VGA mode screen 12 (most others too)
RE: DEF SEG ADDRESSES
I believe even Vesa modes bank the data through this segment... (Not Sure)
Have Fun, Be Young... Code BASIC
-Josh
http://cubee.topcities.com
RE: DEF SEG ADDRESSES
and I also have 1 more question what is a buffer and what does it mean. THX
RE: DEF SEG ADDRESSES
A buffer is an area of memory set aside to receive data.
rgds
Zeit.
RE: DEF SEG ADDRESSES
&HFFA6 is where the bios font is stored.
doing....
DEF SEG = &HAFFA6
...points to this location. Then you can use PEEK to retrieve the font data. Here's a small SUB that uses this method which prints words on the screen without using PRINT.
DEFINT A-Z
DECLARE SUB BIOSPRINT (x%, y%, Text$, clr%)
SCREEN 13
BIOSPRINT 12, 12, "Hello", 12
DEFSNG A-Z
SUB BIOSPRINT (x%, y%, Text$, clr%)
'================================
'x%, y% = location to print.
'Text$ = Text to print
'clr% = Color of text
'================================
FOR d% = 1 TO LEN(Text$)
FOR c% = 0 TO 7
DEF SEG = &HFFA6
l% = PEEK(14 + 8 * ASC(MID$(Text$, d%, 1)) + c%)
x1% = x% + d% * 8 - 1
x2% = x% + d% * 8 + 15: a% = 7
FOR b% = x1% TO x2%
IF l% AND 2 ^ a% THEN
PSET (b%, c% + y%), clr%
END IF: a% = a% - 1
NEXT
NEXT
NEXT
DEF SEG
END SUB
People often use method instead PRINT because the text has a transparent background,instead of blocking out the background the way PRINT does.
- Dav
My Qbasic Source code....
http://sys.blissdev.com/dav/
RE: DEF SEG ADDRESSES
RE: DEF SEG ADDRESSES
Such as a video buffer... it is an area (or array) of memory where you use to set up the screen for quick 'flipping'... this way you don't see the changes being made to the image until it is done... also, it is usually faster to use 'Normal' memory then Video memory to quickly read and write multiple data... Such as with blurring filters...
A keyboard buffer is another area of memory where the keypresses are processed and sent so you can go and see what keys were pressed...
Inkey$ reads from the keyboard buffer...
Inp(96) aka Inp(&h60) reads directly from the port...
If you use Inp(96), the buffer is bypassed and you must clear it out or it will overflow and begin to beep...
Have Fun, Be Young... Code BASIC
-Josh
http://cubee.topcities.com
RE: DEF SEG ADDRESSES
RE: DEF SEG ADDRESSES
when I POKE a value to it it just changes back? Is there a way to change it? Thx for all the help so far
RE: DEF SEG ADDRESSES
And should not let anything change it...
It stored the Data for the ASCII characters... Such as the ones shown at startup... and Dos Prompt...
Have Fun, Be Young... Code BASIC
-Josh
http://cubee.topcities.com
RE: DEF SEG ADDRESSES
RE: DEF SEG ADDRESSES
NOT THAT I KNOW OF...
And if you did would that change the all of the DOS font?
YES, IT WOULD
Have Fun, Be Young... Code BASIC
-Josh
http://cubee.topcities.com
RE: DEF SEG ADDRESSES
RE: DEF SEG ADDRESSES
Though, I believe Windows NT handles something differently...
Some Qbasic routines to draw Graphic fonts, using the Bios Ascii Character Map, any where on the screen tend to result in scrambled characters when you use the FFA6 segment to get the masks...
So I really don't know where the data comes from or what manages it...
If you find a work around, be sure to post it
Have Fun, Be Young... Code BASIC
-Josh
http://cubee.topcities.com
RE: DEF SEG ADDRESSES