Subject: Re: [stella] FE bank switching again From: Adam Wozniak <adam@xxxxxxxxxxxxxxxx> Date: Fri, 24 Jan 2003 10:15:34 -0800 (PST) |
Ahhh.. Thanks. That's what I was looking for... On Thu, 23 Jan 2003, Eric Ball wrote: > The following (from http://www-2.cs.cmu.edu/~dsladic/vice/doc/64doc.txt) may > help you figure out how FE works: > > RTS > > # address R/W description > --- ------- --- ----------------------------------------------- > 1 PC R fetch opcode, increment PC > 2 PC R read next instruction byte (and throw it away) > 3 $0100,S R increment S > 4 $0100,S R pull PCL from stack, increment S > 5 $0100,S R pull PCH from stack > 6 PC R increment PC > > JSR > > # address R/W description > --- ------- --- ------------------------------------------------- > 1 PC R fetch opcode, increment PC > 2 PC R fetch low address byte, increment PC > 3 $0100,S R internal operation (predecrement S?) > 4 $0100,S W push PCH on stack, decrement S > 5 $0100,S W push PCL on stack, decrement S > 6 PC R copy low address byte to PCL, fetch high address byte > to PCH -- Will code for food. http://cuddlepuddle.org/~adam/resume.html adam@xxxxxxxxxxxxxxxx http://cuddlepuddle.org/~adam/pgp.html ---------------------------------------------------------------------------------------------- Archives (includes files) at http://www.biglist.com/lists/stella/archives/ Unsub & more at http://www.biglist.com/lists/stella/
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