General 8085 question(s)

Discussion in 'Assembly Language Programming (ALP) Forum' started by LanguidLegend, Sep 12, 2011.

  1. LanguidLegend

    LanguidLegend New Member

    Sep 12, 2011
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    Ok, so I've started learning 8085 assembly language on my own a bit, and I have a couple general questions I'm hoping someone can help me clarify..

    So I'm reading this tutorial on 8085 instructions, and I come across example instructions.
    My questions are regarding the binary/hex translations of these instructions..
    First, is there a place where I can find a list of opcode binary representations for every instruction and/or register in the 8085 language?
    Let's take the first instruction in the list for example:
    MOV C, A (copy 8-bit data from accumulator reg to reg C)
    Do registers A and C have specific binary translations regardless of context? (i.e.: A = 111, C = 001) Does MOV?

    And second, why do so many hex codes in with an "H"? What does it mean?

    Any help appreciated!
  2. oldisgold

    oldisgold New Member

    Apr 16, 2012
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    0. Sorry for the belated response; i joined this forum just today & saw your post just now; hope your doubts might have been already cleared long long ago by somebody else; still, let me give you a few words of explanation.
    1. in the opcode (binary) the first 2 bits (01) indicate a MOV operation; next 3 bits indicate the destination regr; here it is 001; it stands for regr C; last 3 bits indicate source regr; here it is 111; it stands for regr A.
    2. the letter H (or h) is suffixed to numbers to indicate they are hex numbers & not the usual decimal numbers; in this case, the H suffix is not necessary, because the column heading in the table clearly says hex code.
    3. you may refer to some good book on 8085 (like "Microprocessors and applications" by Aditya P Mathur) to understand the "field encoding" of opcodes; that is: what the different bits in the opcode mean to the processor; that is: what the processor understands from the different bits in the opcode.

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