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Homework Help: Can someone check if this is correct please

  1. Dec 29, 2009 #1
    1. The problem statement, all variables and given/known data

    If the content of d0 is $30 state in words what each of the following numbered instructions will do when placed immediately after the test instruction below
    tst d0

    2. Relevant equations

    a) bne fred
    b) beq fred
    c) bpl fred
    d) bmi fred

    3. The attempt at a solution

    a) bne fred = [go to label fred] [if d0] [not equal to $30]
    b) beq fred = [go to label fred] [if d0] [equal to $30]
    c) bpl fred = [go to label fred] [if d0] [ plus $30]
    d) bmi fred = [go to label fred] [if d0] [minus $30]


    TST or tst direct against zero instruction.

    This is really the same as compare with zero

    tst <effective address>

    it subtracts 0 from a copy of the location specified and sets the condition flags accordingly.
    If the value to be tested is positive then +N –0 = +N or if negative –N –0= -N or if 0 then 0-0 =0

    tst d0 is d0 equal to 0, greater than zero or less than zero
    beq joe go to label joe if d0 equal to 0
    bgt dan go to label dan if d0 greater than 0
    blt ben go to label ben if d0 less than 0

    iam confused can someone help

    If the content of d0 is $30 state in words what each of the following numbered instruction pairs will do.

    a. cmpi #$30,d0
    beq dan

    b. cmp.l unknown,d0
    bne dan

    c. cmp.w d1,d0
    bgt dan
  2. jcsd
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