Rounding error in floating point division of constant values

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    • Type: Bug
    • Resolution: Unresolved
    • Priority: Low

      The attached file contains this line ...

         if (delay  >= ( (unsigned short) (20e-3/(1e-3)) ) )

      Thus, you would expect the variable delay to be compared with the value 20.

      Build it ...

      % cl2000 -s try1.c

      Then inspect the resulting assembly file to see these lines ...

      ;----------------------------------------------------------------------
;   5 | if (delay  >= ( (unsigned short) (20e-3/(1e-3)) ) )
;----------------------------------------------------------------------
        MOVW      DP,#_delay            ; [CPU_ARAU]
        MOV       AL,@_delay            ; [CPU_ALU] |5|
        CMPB      AL,#19                ; [CPU_ALU] |5|
        B         $C$L1,LO              ; [CPU_ALU] |5|

      It is not compared again 20, but 19.

       

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            TI User
            Reporter:
            TI User
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              Created:
              Updated:

                Connection: Intermediate to External PROD System
                EXTSYNC-2583 - Rounding error in floating point di...
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