The mouse variables ax, bx, cx, dx.....what do they do?


I have got many mouse routines (you would have seen my previous message),

and in them there are 4 variables which frequently occur,

ax, bx, cx, dx. Does anyone know what each of these do,

and e.g. if the dx is the x axis.

Thanking You,



  • Hmmm... AX,BX,CX, and DX are the names of the geneal registers of the x86 family CPU,

    generally used only in assembly. I assume that means the libraries you have are done in

    assembly (which would make sense, Pascal is rather slow for that sort of stuff.)

    If you have access to a decent library or, better yet, a university library, you should

    be able to find plenty of stuff on assembly.

    Assuming that the lib you're looking at polled the mouse driver in the usual way, the

    registers returned have the following meaning:

    CX - X position in pixels.

    DX - Y position in pixels.

    AL - Status of buttons (individual bits have meanings.)


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