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Since I noticed it was some question about how I
solved my program and PC problem, here it is:
I use a ordinary desktop PC wich i really a pain
to carry. I have bought a 9 inch VGA screen to
have less to carry but it is a pain to look at.
I want to have a laptop but I wrote my program for
the graphic card I have and I manipulate it
trhought the VESA 1.2 standard. This standard
however is not a standard but only a recommendation
that the VGA properties should be readable with
BIOS call. Its differ a lot from card to card.
I found alse that even if I do the correct call
to a card it could respond different depending
on the manufacturer. Finally I didn't care to try
to write for a card in general, I wrote for my
Cirrus Logic 5434.
To scroll my image I change the staring point for
the VGA card reading its memory.
To write to the memory I have to define a 64 K
memory window in the PC RAM wich I map over the
VGA card memory. This window is then "scrolled"
over the VGA memory and allows me to write and
read directly to the VGA memory troght a array
defined at a absolute adress in the PC.
The program is written in Pascal and the graphics
access routines is machine code procedures who
does the BIOS calls.
As you may understand, to make this transportable
to every PC is a lot of work.
However... he he.. there is no way doing a faster
scroll than just change the starting point for
the VGA card.
Sture
solved my program and PC problem, here it is:
I use a ordinary desktop PC wich i really a pain
to carry. I have bought a 9 inch VGA screen to
have less to carry but it is a pain to look at.
I want to have a laptop but I wrote my program for
the graphic card I have and I manipulate it
trhought the VESA 1.2 standard. This standard
however is not a standard but only a recommendation
that the VGA properties should be readable with
BIOS call. Its differ a lot from card to card.
I found alse that even if I do the correct call
to a card it could respond different depending
on the manufacturer. Finally I didn't care to try
to write for a card in general, I wrote for my
Cirrus Logic 5434.
To scroll my image I change the staring point for
the VGA card reading its memory.
To write to the memory I have to define a 64 K
memory window in the PC RAM wich I map over the
VGA card memory. This window is then "scrolled"
over the VGA memory and allows me to write and
read directly to the VGA memory troght a array
defined at a absolute adress in the PC.
The program is written in Pascal and the graphics
access routines is machine code procedures who
does the BIOS calls.
As you may understand, to make this transportable
to every PC is a lot of work.
However... he he.. there is no way doing a faster
scroll than just change the starting point for
the VGA card.
Sture