🚀 go-pugleaf

gay@selkirk.sfu.ca (Ian D. Gay) writes:

>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

sorry, not thinking, that should be
     push ds
     mov ax, seg DGROUP
     mov ds,ax
since you cant load a constant to a segment register



>    ......

>    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...

>>------------------------------------------------------------------------------
>>stuartw@ccu1.aukuni.ac.nz

>>   >>>>In VI Where Available<<<<
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