On Tue, 29 Jan 2002, Nicolas Welte wrote: > Recently I had some problems diagnosing RAM failures in two machines > (one SX and one C64A breadbox), because my normal diagnostic ROM did > not come up at all. I wonder if the KERNAL crashed because it relied > on some RAM portions to be okay The portions it relies to be okay are two bytes somewhere at $1f0-$1ff. The RESET routine does just LDX#xx:SEI:TXS:CLD:JSR$xxxx:...:RTS:BEQ/BNE$xxxx:JMP($8000) if the CBM80 text is found at $8004-$8008. The JSR'd routine checks the text, and if the RAM is bad, the RTS at the end of this routine will fail. Stupid design by Commodore, I'd say. Marko Message was sent through the cbm-hackers mailing list
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