bug181 in DMD 2.0.66.1

/* Test program for Digital Mars D (DMD)
** which shows that it has some sort of bug.
*/

import std.stdio;

char filter(uint i) {
    enum bloop = '#'; // traditional substitute for non-printable (hak tradition)
    enum bleck = '.'; // for zero as it is null and not "bloop", but non-printable

    i = i & 0x7f;
    if (i == 0)
        return bleck;
    if (i < 32)
        return bloop;
    else
        return cast(char)i;
}

string ex_18_1b() {
    string textReturned;
    uint r[3];

    uint r1, r2, r3; // NOTE: needed for a workaround of an apparent bug!
    asm {
        mov EAX, 0;
        cpuid;
        mov r1, EBX;
        mov r2, EDX;
        mov r3, ECX;
    }
    r[0] = r1;
    r[1] = r2;
    r[2] = r3;

    textReturned = decode(r, 3);

    return textReturned;
}

string decode(uint[] r, int n) {
    uint wrd;
    int y, x;
    string textReturned;

    bool verbose = true; // NOTE: just to make the bug transparent.

    for (y = 0; y < n; y++) {
        wrd = r[y];
        if (verbose)
            writefln("\tword[%d]:0x%x", y, wrd);
        for (x = 0; x < 4; x++) {
            textReturned ~= filter(wrd);
            wrd >>= 8;
        }
    }

    return textReturned;
}

string ex_18_1() {
    string textReturned;

    uint r[3];

    asm {
        mov EAX, 0;
        cpuid;
        mov r[0], EBX;
        mov r[1], EDX;
        mov r[2], ECX;
    }

    textReturned = decode(r, 3);

    return textReturned;
}

void main()
{
    writefln("Temporary D test program by \"K1pp\".");
    writefln("\tBased on Ex.18-1 in Brey's old book.");
    writefln("This illustrates an annoying DMD bug, or something.\n");

    writefln("CPUID based on Ex 18-1:\n\t\"%s\".\n", ex_18_1() );
    writefln("CPUID based on Ex 18-1, variant 'b':\n\t\"%s\".\n", ex_18_1b() );
}