QUADMATH





                             Quadword Math Routines










                                       by

                              Rodrick A. Eldridge
                             Iowa State University


















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                                    Overview



This paper presents a set of routines which implement, in VAX-11 Macro, quadword
math  routines to add, clear, compare, divide, move, multiply, subtract and test
quadword values.





                                     Notice



In order to reassemble these routines, you must have  the  MLR  Macro  Language.
The  MLR  Macro Language is a set of macro that implement structured programming
in VAX-11 Macro.





                                   References




     1.  VAX ARCHITECTURE HANDBOOK; Digital Equipment Corporation.

     2.  QUADMATH - Quadword Math; HUGHES AIRCRAFT DECUS  SIG  tape  submission.
         [VAX83C.HUGHES]





















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ADDQ  add,sum
ADDQ3 add1,add2,sum



The ADDQ procedure will add one quadword to another and leave the result in  the
second quadword.  The ADDQ3 procedure will add one quadword to another and leave
the result in a third quadword.

After the addition is performed, r0 will contain one of the following values:

        -1      sum < 0
        0       sum = 0
        1       sum > 0

The ADDQ procedure is equivalent to the expression:

        sum = add + sum

and the ADDQ3 procedure is equivalent to the expression:

        sum = add1 + add2


MLR Example:

        var
          add1:         .blkq 1
          add2:         .blkq 1
          sum:          .blkq 1

        external module addq <add,sum>
        external module addq3 <add1,add2,sum>

        addq    add1,sum
        addq3   add1,add2,sum


















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CLRQ dst



The CLRQ procedure will zero a quadword.

After the quadword is cleared, r0 will contain one of the following value:

        0       dst = 0

The CLRQ procedure is equivalent to the expression:

        dst = 0


MLR Example:

        var
          dst:          .blkq 1

        external module clrq <dst>

        clrq    dst































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CMPQ src,dst

The CMPQ procedure will compare a quadword with another quadword.

After the comparision is performed, r0 will contain one of the following values:

        -1      src < dst
        0       src = dst
        1       src > dst


MLR Example:

        var
          src:          .blkq 1
          dst:          .blkq 1

        external module cmpq <src,dst>

        cmpq    src,dst


































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DIVQ4 divisor,dividend,quotient,remainder



The DIVQ4 procedure will divide one quadword with another quadword and leave the
quotient and remainder in two other quadwords.

After the division is performed, r0 will contain one of the following values:

        -1      quotient < 0
        0       quotient = 0
        1       quotient > 0

The DIVQ4 procedure is equivalent to the expression:

        (quoitent,remainder) = divisor / dividend


MLR Example:

        var
          divr:         .blkq 1
          divd:         .blkq 1
          quo:          .blkq 1
          rem:          .blkq 1

        external module divq4 <divr,divd,quo,rem>

        divq4   divr,divd,quo,rem

























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MOVQ src,dst



The MOVQ procedure will move one quadword to another quadword.

After the quadword is moved, r0 will contain one of the following values:

        -1      dst < 0
        0       dst = 0
        1       dst > 0

The MOVQ procedure is equivalent to the expression:

        dst = src


MLR Example:

        var
          src:          .blkq 1
          dst:          .blkq 1

        external module movq <src,dst>

        movq    src,dst




























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MULQ  multiplier,product
MULQ3 multiplier,multipland,product



The MULQ procedure will multiply one quadword with another and leave the  result
in  the  second  quadword.   The MULQ3 procedure will multiply one quadword with
another and leave the result in a third quadword.

After the multiplication is performed, r0 will  contain  one  of  the  following
values:

        -1      product < 0
        0       product = 0
        1       product > 0

The MULQ macro is equivalent to the expression:

        product = multiplier * product

and the MULQ3 macro is equivalent to the expression:

        product = multiplier * multipland


MLR Example:

        var
          mulr:         .blkq 1
          muld:         .blkq 1
          prod:         .blkq 1

        external module mulq <mulr,prod>
        external module mulq3 <mulr,muld,prod>

        mulq    mulr,prod
        mulq3   mulr,muld,prod

















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SUBQ  sub,dif
SUBQ3 sub,min,dif



The SUBQ procedure will subtract one quadword from another and leave the  result
in  the  second  quadword.   The SUBQ3 procedure will subtract one quadword from
another and leave the result in a third quadword.

After the subtraction is performed, r0 will contain one of the following values:

        -1      dif < 0
        0       dif = 0
        1       dif > 0

The SUBQ macro is equivalent to the expression:

        dif = sub - dif

and the SUBQ3 macro is equivalent to the expression:

        dif = sub - min


MLR Example:

        var
          sub:          .blkq 1
          min:          .blkq 1
          dif:          .blkq 1

        external module subq <sub,dif>
        external module subq3 <sub,min,dif>

        subq    sub,dif
        subq3   sub,min,dif


















                                - 9 -



TSTQ dst



The TSTQ procedure will test a quadword with zero.

After the test is performed, r0 will contain one of the following values:

        -1      dst < 0
        0       dst = 0
        1       dst > 0


MLR Example:

        var
          src:          .blkq 1

        external module tstq <src>

        tstq    src

































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                                Index



ADDQ, 3                             MOVQ, 7
ADDQ3, 3                            MULQ, 8
                                    MULQ3, 8
CLRQ, 4
CMPQ, 5                             SUBQ, 9
                                    SUBQ3, 9
 
DIVQ4, 6                            TSTQ, 10










































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