"The Wizard of Oz" <wizard@emeraldcity.gov> wrote in message
news:pan.2004.08.26.20.49.25.483509@emeraldcity.gov...
> Quick question... First off I managed to do this 10 years ago and can't
> find the program source. It must be on a dead hard drive.
>
> I want to be able to access the RAMRD and RAMWT switches from assembler.
> I'm using 8bit Merlin (thanks for the manual Bill). According to an older
> //e manual I have, the only thing I have to do is make sure 80STORE is
> off. Regardless of the settings of 80STORE when I do a "STA RAMRD"
> followed by a "LDA (somezeropage),Y" it looks as though there is a branch
> occurs into page 1. Specifically into an area I have for tables. Has
> anybody encountered this? Also can someone provide me with a quick code
> segment they use to get these switches working. (FYI, I'm writing the
> program on a ROM 03 GS and testing it on a ROM 01 GS with the eventual
> users being //e and //c folks.)
>
> This was going to be the last subroutine for the utility, but I just
> thought of another useful one. I've been working on this for 8 - 10 months
> and I really want to finish up.
>
> Later
> Mike

READAUX    EQU $C003
READMAIN  EQU $C002
WRTAUX      EQU $C005
WRTMAIN   EQU $C004
AUXZP         EQU $C009
MAINZP      EQU $C008

    ORG $100    ;DANGER USING 35 BYTES OF STACK MEMORY
    STA MAINZP  ;USE MAIN MEMORY ZERO PAGE AND STACK
    LDA    #0
    STA    $F0
    LDA    #$10
    STA    $F1    ;BASE ADDRESS $1000
    LDA    #$AA
    STA    WRTAUX    ;AUXMEM WRITE ACTIVE
    STA    $10FF    ;STORE $AA IN AUXMEM LOCATION $10FF
    STA    WRTMAIN    ;EVERYTHING IN MAIN AGAIN
    STA    READAUX    ;READING AUXRAM
    LDA    #0    ;ZERO ACCUMULATOR
    LDY    #$FF
    LDA    ($F0),Y    ;READ AUXMEM LOCATION $10FF
    STA    READMAIN    ;EVERYTHING IN MAIN, A CONTAINS $AA
    BRK

Notice I used stack memory....
If you have plenty of memory to play with the easiest thing to do would be
to copy your read aux routine to auxmem. When you trigger the read aux
switch the 6502 will get its next byte (instruction) from the auxmemory.

If I had assembled the above at $300 I could add a read main ,write aux and
copy the
    LDA    #0    ;ZERO ACCUMULATOR
    LDY    #$FF
    LDA    ($F0),Y    ;READ AUXMEM LOCATION $10FF
    STA    READMAIN    ;EVERYTHING IN MAIN, A CONTAINS $AA
instructions to auxmem $3xx and execution would be as expected.

If your readaux is somewhat more complicated, assemble it for auxmem and
read it into memory and use the $C311 auxmove to locate it in auxmem.
in zero page have sta readaux jmp mycode.