On Fri, 20 Jan 1995 11:02:50 GMT, Brian Gaff Sam Dept. said: > I have been thinking.. (dangerous) As SAM in a mass produced for > is basically dead, I wonder what sort of PC would be needed to > emulate it?
I would say that if you used the software Z80 emulation of, say, Z80, then a graphics board and a sound chip would be sufficient. The sound chip would obviously be a Philips one identical to the Sam's. The graphics board would have to have either DMA or on-board memory in order to store the following information. * a memory image of the screen (between 6K and 24K) * palette info, including mid-screen palette changes * mode info, including mid-screen mode changes. If it didn't do this, then making a complete emulation would be a real pain because the mode can change on any part of the screen at a moment's notice and that would require a whole lot of processing to emulate in software. However, perhaps a SuperEmulator(tm) such as Arnt's proposed QAOP might be able to spare enough processing time to recreate the video whenever necessary. The software emulation should be able to count cycles and generate line interrupts at the correct times. Whenever the palette or mode changes, it should be able to work out what position on the screen to make the change from the cycle count. imc
