APPENDIX B
move.w #7, - (sp) * push XBIOS command number on
stack
trap #14 * call XBIOS handler
addq.l #6,sp * pop parameters (6 bytes) off stack
Calling the XBIOS routines from C is much simpler.
Most C compilers come with a library routine called xbios(),
that stacks the parameters and executes the TRAP #14 in
struction. For example, the sample call illustrated above
could be accomplished in C by the single statement
xbios(7,0,0x770);
Since it's easier to remember a command name than a
command number, most C compilers include a header file
called OSBIND.H.H that defines macros for all of the XBIOS
functions. For example, the macro definition for XBIOS com
mand 7 is:
#define Setcolor (a,b) xbios(7,a,b)
Therefore, after you #include OSBIND.H.H in your pro
gram, you can call the sample function like this:
Setcolor(0,0x777);
The C macro format is the one most commonly found in
discussions of XBIOS routines and sample programs. To use
XBIOS functions in your C programs, you must #include
OSBIND.H if you use the macros, and you must link your
program with the compiler library that contains the xbios()
function.
190
To Next Page
Loading...
