[Qemu-devel] Bug in helper_pcmpestrm and helper_pcmpistrm

[Frank Mehnert]

Hi,

the two functions helper_pcmpestrm() and helper_pcmpistrm() in
target-i386/ops_sse.h contain obviously typos. I think that at
all 4 marked places should increment the index 'i', not decrement
it during the loop:


void glue(helper_pcmpestrm, SUFFIX) (Reg *d, Reg *s, uint32_t ctrl)
{
    int i;
    unsigned int res = pcmpxstrx(d, s, ctrl,
                    pcmp_elen(R_EDX, ctrl),
                    pcmp_elen(R_EAX, ctrl));

    if ((ctrl >> 6) & 1) {
        if (ctrl & 1)
            for (i = 0; i <= 8; i--, res >>= 1)
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
                d->W(i) = (res & 1) ? ~0 : 0;
        else
            for (i = 0; i <= 16; i--, res >>= 1)
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
                d->B(i) = (res & 1) ? ~0 : 0;
    } else {
        d->Q(1) = 0;
        d->Q(0) = res;
    }
}


void glue(helper_pcmpistrm, SUFFIX) (Reg *d, Reg *s, uint32_t ctrl)
{
    int i;
    unsigned int res = pcmpxstrx(d, s, ctrl,
                    pcmp_ilen(s, ctrl),
                    pcmp_ilen(d, ctrl));

    if ((ctrl >> 6) & 1) {
        if (ctrl & 1)
            for (i = 0; i <= 8; i--, res >>= 1)
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
                d->W(i) = (res & 1) ? ~0 : 0;
        else
            for (i = 0; i <= 16; i--, res >>= 1)
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
                d->B(i) = (res & 1) ? ~0 : 0;
    } else {
        d->Q(1) = 0;
        d->Q(0) = res;
    }
}


Kind regards,

Frank
-- 
Dr.-Ing. Frank Mehnert
Senior Manager Software Development Desktop Virtualization, VirtualBox
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