🚀 go-pugleaf

stuartw@ccu1.aukuni.ac.nz (Stuart Woolford) writes:


> A friend of mine has a small problem with the useage of Msoft mouse drivers...

>How do you write a routine in pascal ( or C...asm...etc ) which will be called
>by the standard callback function of the driver ( when a button is pressed, etc
>), and which can still address the programs global variables, the problem is
>that, when the routine is called, DS points at the MOUSE DRIVERS data segment,
>and I at least could not think of an easy way to address the programs global
>data, which will NOT be at a fixed address :-(


I have used the following as inline assembler with Turbo-C. It works. 
I couldn't think of a pure C way to do it.

    push ds
    mov  ds seg DGROUP

    ......

    pop ds

This works because T-C keeps its global variables in a group called 
DGROUP. Basically what you have to do is get ds loaded with a 
_constant_ of the correct value, since no registers have what you want 
when the call occurs. The above code generates such a constant (fixed 
up at link time, of course).


>Also, he said that there is a problem with the mouse in all 256 color VGA modes
>( under TP 6.0, using BGI's ), any comment ????

Are BGI's supposed to support the mouse? The usoft mouse driver 
doesn't really support anything but the standard IBM video modes, i.e. 
only 320x200 (yecch!) if you want 256 colours. You can do it yourself, 
the hard way, by only using the lowest level mouse calls, and 
drawing/erasing the pointer yourself, as required.


>any replies appreciated...

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>stuartw@ccu1.aukuni.ac.nz

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