🚀 go-pugleaf

In <1992Dec27.000209.19554@proto.com> joe@proto.com (Joe Huffman) writes:

>rwallace@unix1.tcd.ie (russell wallace) writes:

>>Basically the method of accessing screen memory I'm using is with a far
>>pointer with segment = B800h and offset = row*160 + column*2, to give a
>>pointer to the character+attribute at (row,column). This works fine in
>>tiny, small, large etc. memory models, but does not work in extended
>>(option mx) memory model - as soon as I try to write a value into the

>The following should work:

>#include <dos.h> /* For the declaration of _x386_zero_base_selector. */
>		 /* Also, MK_FP() is prototyped. */
>int main()
>{
>  char _far *screen_ptr = MK_FP(_x386_zero_base_selector, 0xb800);

>  /* Now use the screen_ptr as you normally would, it points to the base
>     address of the start of the screen. */

>  /* If you get the X-32VM extender (the successor to DOSX) from FlashTek,
>  there is a near pointer that points to the start of memory 0000:0000 that
>  you could also use for somewhat faster access.   It is called 
>  _x32_zero_base_pointer (or ptr, I forget right now). */
>}

Thanks, this works perfectly! (Except the typo: 0xb800 in the above
should read 0xb8000. With this, there are no further problems.)
--
"To summarize the summary of the summary: people are a problem"
Russell Wallace, Trinity College, Dublin
rwallace@unix1.tcd.ie