Le mercredi 23 décembre 2009 à 10:55 +0000, Paul Brook a écrit : > > The problem is that the whole define is just plain wrong which tells me > > that the code is using the bswap functions incorrectly. This really > > needs to be fixed by someone who knows the dbdma device. I don't see how > > calling incorrect calls even more incorrect makes any difference. > > The real problem is that devices shouldn't be doing byteswapping at all. This > should be determined by the (currently non-existant) bus layers and > implemented in generic code before the device callback. > > The current code[1] is a nasty hack that sort-of works for most of the > current > machines because all devices happen to be connected the same way. However > there are other machines (e.g. ixp4xx) some peripherals are connected > natively, whereas others are cross-wired. > > On a related note, I'm not sure what the author of mac_bdbma.c was > smoking[2].
I didn't smoke... just need some sleep. > It appears to keep register values in big-endian form for no good reason. > Much > easier would be to store them in native form, and just do the byteswapping > when accessed by the CPU. > > Paul > > [1] e.g. vga.c:vga_mem_readw > [2] My guess is that the code is cribbed from elsewhere, and the original > source gave the CPU direct access to the ch->regs[] array. >From pearpc io/macio/macio.cc. Regards, Laurent -- --------------------- laur...@vivier.eu ---------------------- "Tout ce qui est impossible reste à accomplir" Jules Verne "Things are only impossible until they're not" Jean-Luc Picard
