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From: ccs016@deneb.UUCP
Newsgroups: comp.sys.ibm.pc
Subject: Re: Direct video access
Message-ID: <769@ucdavis.UUCP>
Date: Thu, 17-Sep-87 16:33:51 EDT
Article-I.D.: ucdavis.769
Posted: Thu Sep 17 16:33:51 1987
Date-Received: Sat, 19-Sep-87 09:42:51 EDT
References: <7871.1678.forumexp@mts.rpi.edu>
Organization: University of California, Davis
Lines: 29

> 
>    I know you can get the current MODEM and video PAGE from
>    INT 0x10. These numbers are also stored in low (0:400) memory.
>    Are the values in low memory always (100%) accurate?
> 
>    Also, I've come up with some direct video read/write routines.
>    I seem to get trouble when I use pointers (*vidp = buf[i], etc.
>    where vidp is a far pointer pointing to the current video page)
>    but if I use PEEKs and POKEs I have no problems. Is there
>    a problem with using far pointers (vidp = ((unsigned char *) 0xB800)

     Yes, you forgot the offset. Just add on more 0's on your address. 
 
main()
{
  long address = 0xb800000;
  char far buf;
  int x;

  buf = (char far *) address;
  for (x=1;x<4000;x+=2)        /* skip the attributes */
      printf("%c",*buf++);
}
  
     This should work. I just wrote this so please don flame me. However,
it has worked in the past. 
 
Patrick Tully
pstully@ucdavis