Re: [stella] FE bank switching again

Subject: Re: [stella] FE bank switching again
From: "Eric Ball" <ericball@xxxxxxxxxxxx>
Date: Thu, 23 Jan 2003 21:31:32 -0500
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

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