QBlit

Queue up a request for blitter usage

Link a request for the use of the blitter to the end of the current blitter queue. The pointer bp points to a blit structure containing, among other things, the link information, and the address of your routine which is to be called when the blitter queue finally gets around to this specific request. When your routine is called, you are in control of the blitter ... it is not busy with anyone else's requests. This means that you can directly specify the register contents and start the blitter. See the description of the blit structure and the uses of QBlit in the section titled Graphics Support in the OS Kernel Manual. Your code must be written to run either in supervisor or user mode on the 68000.

bp

pointer to a blit structure

Your routine is called when the blitter is ready for you. In general requests for blitter usage through this channel are put in front of those who use the blitter via OwnBlitter and DisownBlitter. However for small blits there is more overhead using the queuer than Own/Disown Blitter.

Code which uses QBlit(), or QBSBlit() should make use of the pointer to a cleanup routine in the bltnode structure. The cleanup routine may be called on the context of an interrupt, therefore the routine may set a flag, and signal a task, but it may not call FreeMem() directly. Use of the cleanup routine is the only safe way to signal that your bltnode has completed.

QBlit(), and QBSBlit() have been rewritten for V39 due to various long standing bugs in earlier versions of this code.

QBSBlit() <hardware/blit.h>