Write an image to the frame buffer (DrawImage)

The DrawImage(D3nfb) routine in the Image.c file writes an image to the frame buffer. Note the following:

• DrawImage(D3nfb) needs to be able to draw a rectangular area on the screen, applying the given alu and planemask; see ``alu''. You will probably need to set up a static table of size 16 that takes the alu value as an index and returns the actual value required by the hardware. See ``alu''.

• The sample driver uses C defines to create a series of macros that will be used extensively to set the planemask value, the alu value, the various drawing command registers, the drawing coordinates, and so forth. You should attempt to use a similar paradigm in your driver to map the alu functions (especially GXcopy, GXxor, and GXinvert to the adapter's operations.

• Once DrawImage( ) has been written, it may be possible to run the X server in an almost usable manner. The cursor code leave tracking on the screen, and expects ReadImage(D3nfb) to be correctly implemented, but otherwise you should be able to start X clients and see their output on your graphics adapter.