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Altera_Forum's avatar
Altera_Forum
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13 years ago

mod - remainder confiusion

Dear all,

Anyone can explain what mean by this line of code:

ad<=(-5) mod 8;

I know the "mod" is the remainder. But, why need negative? What the different with ad<=5 mod 8? Thanks in advance

3 Replies

  • Altera_Forum's avatar
    Altera_Forum
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    13 years ago

    While I am not sure if this is the helpful or not (as I can not see the context of your code):

    5 as a byte:

    0b00000101

    -5 as a byte (one's complement):

    0b11111010

    -5 as a byte (two's complement):

    0b11111011
  • Altera_Forum's avatar
    Altera_Forum
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    13 years ago

    Do some simple maths...

    If you divide 13 by 8 you get 1 remander 5.

    If you divide 13-8 (= 5) by 8 you get 0 remainder 5.

    If you divide 13-8*2 (= -3) by 8 you get -1 remainder 5 (or 0 remainder -3).

    If you divide 13-8*3 (= -11) by 8 you get -2 remainder 5 (or -1 remainder -3).

    Which of the quotient and remainder is negative varies according to the definition used by the language.
  • Altera_Forum's avatar
    Altera_Forum
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    13 years ago

    --- Quote Start ---

    Do some simple maths...

    If you divide 13 by 8 you get 1 remander 5.

    If you divide 13-8 (= 5) by 8 you get 0 remainder 5.

    If you divide 13-8*2 (= -3) by 8 you get -1 remainder 5 (or 0 remainder -3).

    If you divide 13-8*3 (= -11) by 8 you get -2 remainder 5 (or -1 remainder -3).

    Which of the quotient and remainder is negative varies according to the definition used by the language.

    --- Quote End ---

    Hai all,

    Actually I try to understand this code example. I used this code as my reference to rewrite my own code later. One more thing, I try to view the state machine diagram using Quartus, but it said that "no state machine". I search from this forum, it said that I need to add reset case to create the state machine automatically. How to add the reset case? Thanks for quick reply