Heinrich Tillack just emailed me with this rather cool news for us Dreamcast sceners:
hi !
SH4 DMAC demo
Yeah, my first working SH4 DMAC demo.
I use DMAC channel 1 in this demo to copy large data amounts to the videoscreen!
This demo also shows how the PVR DMA, Store queues (SQ) and the CPU is performing this copy operation.
(There is also code for Colortable DMA which is not working.)
download at http://a128.ch9.de
Some results of this test:
Results for 1000 loops and 640*480*4 bytes transfer each loop:
test memory Sh4->PVR
51344 ms dmac 32bit mode
16298 ms dmac 256bit mode
40782 ms cpu loop
16321 ms sq loop
6222 ms dma loop
test memory Sh4->Sh4
8920 ms dmac 256bit copy loop
18966 ms CPU 32bit copy loop