Howdy, Stranger!

It looks like you're new here. If you want to get involved, click one of these buttons!

Categories

assembler , disassembler for AM2900

nasernaser Member Posts: 17
Hi all
i want to get disassembler for Am29xx series 4 slicebit processor.
please tell me where i find this Tools.
Thanks

Comments

  • big_endianbig_endian Member Posts: 20
    Oh Lord!

    That is a really old bit slice processor and is no longer being made.
    Something I have to relay to you about bit slice processors vs.
    standard off the shelf (pre-made) processors. A bit slice processor
    is a very basic processor (a sub component of a CPU) where you put one
    or more of them in a bus line, and connect carry lines and other logic
    to these processors to make it into a general purpose CPU. All a bit
    slice is, is a section of a processor, I have seen ALUs and straight
    Integer based bit slices. Basically you use a bunch of different bit
    slice processors together to make a CPU aka central processing unit.

    So in order to understand what a bit slice processor is doing by itself
    or in conjunctions with other logic devices, you need to look at it from
    an electronics standpoint as well, running through the truth tables in
    logic (learn boolean algebra, it is your best friend for programming and
    reducing the amount of logic required to get what you want for an end
    result).

    Trying to get a disassembler for for a 2900 or 2904 bit slice is darn
    near impossible, they didn't have those back then. Everyone was using
    hardware monitors with register & return switches, and other primative
    equipment.

    Here is something that will bake your noodle.

    In order to get an assembler or disassembler for a processor
    it must first have microcode embedded in the core of the processor.

    CPUs and DSPs have microcode

    Bit slice processors do not have microcode

    Therefore you can't disassemble the programming the normal way.
    The primative way of doing what microcoding does for the instruction
    registers (and execution units do) is figure out the logic that
    your bit slice processor is using currently. The way in which
    bit slices operated until it got a clocking, buffering, and execution
    unit with a reference ROM (microcode) to look into and execute internal
    logic, was to hardcode logic gates to do certain tasks. Believe me,
    this is quite annoying when you are first learning how to do this.

    To better understand what I am refering to, look for the old AMD
    29xxx product guides online, they have sample circuits, and the
    logic tables (discreet logic or PALs you need to burn or build)
    in order to get a working Central Processing Unit that can use
    a really small ROM to load microcode from.

    I hope you're an electronic / electrical engineer, otherwise
    you are going to run into some serious trouble trying to comprehend
    processor bit slice architecture and what you need to be able
    to make a processor out of it, then write an assembly / disassembler
    monitor for the new processor you have created out of the bit
    slice (Building Blocks for a CPU).

    I know this probably is confusing you.

    The bit slices are nothing more than building blocks for a real CPU.
    Building blocks don't use assembler and disassemblers, it is
    all based on logic gates and other discreet devices at that level.
    What you need to do is make a virtual processor out of the bit slices
    with gates, registers, and other glue logic (the stuff that makes the
    whole thing work together), like a timing chip with buffer, etc.). It
    complex from here on out.

    Now, instead of trying to do something like that with an AM2900 or
    AM2904, try using an in circuit simulator you can get for the PC
    to make virtual processors, and build the CPU out of blocks on there,
    run simulations, and if you find a version of a processor you like and
    think it will do well, have it burn a PGA or PIC processor for you with
    the layout you describe and logic tables you have designed. This saves
    your sanity, trust me! Plus that program is a lot faster than you, it
    can take years out of development time, can check for logic problems /
    errors, and simplify the circuits to get a faster processor.

    That idea is a Win-Win situation.

    The only disassemblers and assemblers that were available for the
    AMD 29xxx series processors were the math co-processors, the AMD 29000
    series not to get confused with the bit slice 2900 or 2904 or the rare
    2908 (8-bit, bit slice processor).

    : Hi all
    : i want to get disassembler for Am29xx series 4 slicebit processor.
    : please tell me where i find this Tools.
    : Thanks
    :



Sign In or Register to comment.