kvisc/vm/in/string.c

// The OS/K Team licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.

#include <in/instrs.h>

//----------------------------------------------------------------------------//

#define STR_MOVE(reg, len)                                                  \
    if (!(R(RFX) & DF)) R(reg) += len;                                      \
    else R(reg) -= len;

//----------------------------------------------------------------------------//

static void scas_impl(acc_t *p1, acc_t *p2, uint len)
{
    if (p1->type != A_REG)
        _except(E_ILL, "SCASX given a non-REG operand");

    while (R(RCX) > 0)
    {
        ulong x = readmemzx(R(p1->reg), len);

        if (x == 0 || x == p2->val)
            break;

        R(p1->reg) += len;

        R(RCX)--;
    }
}

IMPL_START(scasb, 2) { scas_impl(p1, p2, 1); return 0; }
IMPL_START(scasw, 2) { scas_impl(p1, p2, 2); return 0; }
IMPL_START(scasd, 2) { scas_impl(p1, p2, 4); return 0; }
IMPL_START(scasq, 2) { scas_impl(p1, p2, 8); return 0; }

//----------------------------------------------------------------------------//