cgfour(7D)




NAME

     cgfour - P4-bus 8-bit color memory frame buffer


SYNOPSIS

     /dev/fbs/cgfourn


DESCRIPTION

     The cgfour is a color memory frame buffer with a  monochrome
     overlay  plane  and an overlay enable plane. It provides the
     standard frame buffer interface as defined in fbio(7I).

     In addition to  the  ioctls  described  under  fbio(7I)  the
     cgfour  interface  responds  to two cgfour-specific colormap
     ioctls, FBIOPUTCMAP and FBIOGETCMAP. FBIOPUTCMAP returns  no
     information  other  than  success/failure  using  the  ioctl
     return value. FBIOGETCMAP returns  its  information  in  the
     arrays pointed to by the red, green, and blue members of its
     fbcmap structure argument; fbcmap is defined in <sys/fbio.h>
     as:

     struct fbcmap {
          int  index;             /* first element (0 origin) */
          int  count;             /* number of elements */
          unsigned  char *red     /* red color map elements */
          unsigned  char *green;  /* green color map elements */
          unsigned  char *blue;   /* blue color map elements */
     };

     The driver uses color board vertical-retrace  interrupts  to
     load the colormap.

     The cgfour has an overlay plane colormap, which is  accessed
     by  encoding  the  plane group into the index value with the
     PIX_GROUP macro (see <sys/pr_planegroups.h>).


FILES

     /dev/fbs/cgfour0


SEE ALSO

     mmap(2), fbio(7I)


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