I Need Technical Help

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bryybow49er

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Joined
Jan 14, 2002
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3
Where can I get information on the Programmable Interrupt Controller and or a Memory Map which includes The Interrupt Vectors.
For a Compaq PC running Windows 98 2nd Edition

What I am looking for is the address of the interrupt vector which
points to the extended ASCII set, (CHR$(128) and up)
So that I can reprogram the extended characters to make my own custom characters to use in a Dos program I wrote in Quick Basic.
 
Joined
Nov 25, 2000
Messages
8,994
Hi bryybow49er,

Welcome to this site.
I think you can get to a lot of extended ASCII Chrs from
the keyboard, but i didnt know you could make custom ones.
Best of luck with it.

John
 
 

bryybow49er

Thread Starter
Joined
Jan 14, 2002
Messages
3
Hi John Thanks for responding to my post
On my old PC 8088 this code would produce a crescent Moon Two characters wide when I wrote PRINT CHR$(128)+CHR$(129)
But on the new computers they changed the addresses of the Interrupt Vectors.

CLS
DATA 31,49,0,0,0,49,31,0,248,142,227,99,227,142,248,0
DEF SEG = &H3000
FOR N = 0 TO 15
READ Q
POKE N, Q
NEXT N
DEF SEG = 0
POKE 124, 0
POKE 125, 0
POKE 126, 0
POKE 127, &H30
PRINT CHR$(128) + CHR$(129)
END
 
Joined
Nov 25, 2000
Messages
8,994
Hi Brian,

i used to write stuff in basic.
but ive never tried to run it on a newer machine.

please tell me if i go wrong with this:

CLS
clear screen, on some machines this also sets the cursor position.
DATA
system waits for user input.
DEF SEG
dont know, probably the location to start data.
FOR N=0 TO 15
instruction to loop round from following next 15 times
READ Q
probably to display some previous entry from data
POKE N,Q
instruction to insert entry Q into mem location N
NEXT N
increments mem location
DEF SEG=0
re-assigns the seg to 0
POKE
POKE
POKE
POKE
puts zeros in
PRINT CHR$(128) + CHR$(129)
operates printer
END
this is needed on some progs to return to prompt

Well its not a calculation,
Im not good enough to tell what it is.

Whats it for?

John
 

bryybow49er

Thread Starter
Joined
Jan 14, 2002
Messages
3
Hi John

The CLS just clears the screen in Basic and it does the same in Quick Basic on a new Machine.
The Data is read by the Read Q statment and is placed in memory
by the POKE statment in a place defined by the
DEF SEG = &H3000 statment.
The data is a binary pattern in decimal form. This is how all ASCII
charaters are made.
DEF SEG = 0, POKE 124 is the location of the interrupt vector and the 0's and the &H30 are offsets that tell the computer where to look for the data to make charater 128 and up. And in old basic, GW Basic as well as Quick Basic on a new computer when you write PRINT CHR$(128), the first extended ASCII chareter is printed on the computer screen.
I learned how to do this from the old book by Robert Jourdain
Programmer's Problem solver for the IBM PC
I know that there is somebody out there who knows how to do this on a new computer it's just a question where the interrupt vectors is.
 
Joined
Nov 25, 2000
Messages
8,994
Would i be right that this little prog
is just to make a character for you to use?

A moon shaped character?

I suppose if this little prog were sent with
mail, then the character could be used on the
recieving machine as well?

I remember trying to find the screen addresses
on an old machine, it took a long time.
I did it by using the 'copy' command for a section
of mem at a time.

When the screen filled with the letter i had copied
that indicated the section.
Then i copied into smaller sections with another
letter to narrow it further.
Finally i was able to define the memory locations
for the screen area.

That doesnt sound very hard, but it took me a while
to figure a way, and do it.

You can get direct access to mem locations in WIN by
using the 'DEBUG' command.

Alongside are the ascii chrs for the assembler bytes.
So if you have a rough idea of where the character
set is, you might find the locations by looking for
them.

I havent used any of this kind of stuff since 3.1 hit
the streets, im sorry i have no suggestions for you
but there are so many smart people that come and go
on this site that i am sure you will get the info
that you want. Personally, i dont see where the
interrupts are involved in custom making a pair of
characters from assembler.
That probably shows my lack of knowledge.

So long as this thread is up, sooner or later someone
will see it and know exactly what you need.
Best of luck,
John
 
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