Did a big clean/tidyup of neogeo.c, removed various un-needed codes, commented out code for games i'm not implementing... and finally found a fix for svcplus/svcplusa. I'd left out the px_hack routine. Now, every driver for which I have the roms is working! Decided to add kof10thu and kf10thep, only to discover I don't possess the encrypted kof10thu roms. Therefore I made a kf10thud and substituted the p1 and s1 roms from the nrx set. Two more working games! While watching kof10th attract mode, I discovered that the neogeo/snk screen is corrupted. Since my new kf10thud uses exactly the same c roms without problems, the fault must lie either in the p1-program, or in the driver. This needs to be investigated. This exercise has been a great learning experience, I have thoroughly enjoyed it. Thanks to James for his assistance!