The following program does not run as expected, since it performs a signed comparison (jge in asm) instead of an unsigned comparison (jae in asm) when comparing unsigned shorts. Is this correct or is it a bug?

I do not know how the integral promotion rules are applied in this case. But if I cast the (k-l) to (unsigned short)(k-l) it works as desired.

// Compile with
// dmc -3 -mn -o+all -cod test.cpp
// or
// dmc -3 -mx -o+all -cod test.cpp x32.lib
//
// run as: test x x

#include <stdio.h>

int main(int argc, char argv[])
{
    unsigned short j,k,l;

    j = argc;
    k = j+1;
    l = k+5;

    if (j > (k-l))
    {
        printf("j greater\n");
    }
    else
    {
        printf("j not greater\n");
    }

    return(0);
}

Tim

That's how C works with the integral promotion rules. The unsigned shorts get promoted to ints, which are signed.

"tjulian" <tjulian@removethis.oldi.com> wrote in message news:MPG.18bc1125c83c2330989681@news.digitalmars.com...
> The following program does not run as expected, since it performs a signed comparison (jge in asm) instead of an unsigned comparison (jae in asm) when comparing unsigned shorts. Is this correct or is it a bug?
>
> I do not know how the integral promotion rules are applied in this case.
> But if I cast the (k-l) to (unsigned short)(k-l) it works as desired.
>
> // Compile with
> // dmc -3 -mn -o+all -cod test.cpp
> // or
> // dmc -3 -mx -o+all -cod test.cpp x32.lib
> //
> // run as: test x x
>
> #include <stdio.h>
>
> int main(int argc, char argv[])
> {
>     unsigned short j,k,l;
>
>     j = argc;
>     k = j+1;
>     l = k+5;
>
>     if (j > (k-l))
>     {
>         printf("j greater\n");
>     }
>     else
>     {
>         printf("j not greater\n");
>     }
>
>     return(0);
> }
>
> Tim