Date: 2002-10-31 08:40:37
Hi Cameron, >> I was just catching up with old postings and this idea caught my attention. >> C't Aug1985 (German magazine) had an article about simulation of a 65C02 >> with a software 6502 emulator, and so it raises the question how about a >> software 65816. >Did this actually have any code for the 65C02 emulator? My project is just >doing NMOS opcodes. Yep it did. Are you interest (all the text commentary is in German though...) >> I did have some questions about the actually code you used: >> 1) what did your decode routine look like. How did decode the op code and >Well, going back to the vector table, >I just took the opcode, shifted it left, and used that as an index to get >the vector to the servant routine (obviously adding 256 if the high bit >were set), and then did an indirect JMP. Sorry, but the bit-banging part of my brain is on holidays.... so: clc lda (opcode),y ;y=0) asl ; two bytes per JMP vector sta jmpvector bcc + .... sta jmpvector+1 + jmp(jmpvector) ???? or something like that? Regards, - Nick PLEASE TAKE NOTE: The contents of this email (including any attachments) may be privileged and confidential. Any unauthorised use of the contents is expressly prohibited. If you have received this email in error, please advise us immediately (you can contact us by telephone on +61 8 9441 2311 by reverse charge) and then permanently delete this email together with any attachments. We appreciate your co-operation. Whilst Orbital endeavours to take reasonable care to ensure that this email and any attachments are free from viruses or other defects, Orbital does not represent or warrant that such is explicitly the case (C) 2000: Orbital Engine Company (Australia) PTY LTD and its affiliates Message was sent through the cbm-hackers mailing list
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