Altera Embedded Systems Development Kit, Cyclone III Edition - Manual (Page 66)

Altera Corporation Development Board Version 1.0. 9–8
July 2010 Altera Embedded Systems Development Kit, Cyclone III Edition
Using the Nios II C2H Compiler
Figure 9–5. Mandelbrot Engine Pixel Interleaving
While the hardware accelerators are calculating a frame, the coordinates
of the next frame are prepared by the Nios II processor. The hardware
accelerator code contains a C pragma that instructs the compiler to
implement non-blocking accelerator which allows both the main
processor and Mandelbrot hardware accelerator to operate in parallel.
The main processor polls the accelerator to determine if the entire frame
has been rendered.