// 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>

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

IMPL_START(jmp) { R(RIP) = p1->val; return 0; }

IMPL_START(loop) {
    if (R(RCX) > 0) {
        R(RCX)--;
        R(RIP) = p1->val;
    }
    return 0;
}

IMPL_START(b)
{
    ulong v;

    if (ACC_FMT_IS_MEM(p1->type))
        v = readmemsx(ctx, p1->addr, p1->mlen);
    
    else v = p1->val;

    COMPARE_SUB(v, p2->val);

    if (eval_cond(ctx, ctx->cond))
        R(RIP) = p3->val;

    return 0;
}

IMPL_START(cmp)
{
    ulong v;

    if (ACC_FMT_IS_MEM(p1->type))
        v = readmemsx(ctx, p1->addr, p1->mlen);
    
    else v = p1->val;

    COMPARE_SUB(v, p2->val);

    return 0;
}

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

IMPL_START(lea) { *r1 = p2->addr; return 1; }

IMPL_START(mov)
{
    if (ACC_FMT_IS_MEM(p2->type))
        *r1 = readmemsx(ctx, p2->addr, p2->mlen);

    else *r1 = p2->val;

    return 1;
}

IMPL_START(movzx)
{
    if (ACC_FMT_IS_MEM(p2->type))
    {
        if (__builtin_expect(p2->mlen == 8, 0))
            _except(ctx, E_ILL, "MOVZX with qword memory source");

        *r1 = readmemzx(ctx, p2->addr, p2->mlen);
    }

    else *r1 = p2->val;

    return 1;
}

IMPL_START(movsxb) { *r1 = (ulong)(long)(char)(p2->val & 0xFF); return 1; }
IMPL_START(movsxw) { *r1 = (ulong)(long)(short)(p2->val & 0xFFFF); return 1; }
IMPL_START(movsxd) { *r1 = (ulong)(long)(int)(p2->val & 0xFFFFFFFF); return 1; }

IMPL_START(xchg)
{
    *r2 = p1->val;

    if (ACC_FMT_IS_MEM(p2->type))
        *r1 = readmemsx(ctx, p2->addr, p2->mlen);

    else *r1 = p2->val;

    return 2;
}

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

//
// Stack manipulation instructions
//

IMPL_START(push)
{
    ulong v;

    if (ACC_FMT_IS_MEM(p1->type))
        v = readmemzx(ctx, p1->addr, p1->mlen);

    else v = p1->val;

    R(RSP) -= 8;
    writemem(ctx, v, R(RSP), 8);

    return 0;
}

IMPL_START(pop)
{
    *r1 = readmemzx(ctx, R(RSP), 8);
    R(RSP) += 8;
    
    return 1;
}

IMPL_START(call)
{
    R(RSP) -= 8;
    writemem(ctx, R(RIP), R(RSP), 8);
    R(RIP) = p1->val;

    if (p2)
    {
        R(AX0) = p2->val;

        if (p3)
            R(AX1) = p3->val;
    }

    return 0;
}

IMPL_START(ret)
{
    R(RIP) = readmemzx(ctx, R(RSP), 8);
    R(RSP) += 8;

    return 0;
}

IMPL_START(enter)
{
    writemem(ctx, R(RBP), R(RSP) - 8, 8);
    R(RBP) = R(RSP) - 8;
    R(RSP) -= (p1->val + 1) * 8;

    return 0;
}

IMPL_START(leave)
{
    R(RSP) = R(RBP) + 8;
    R(RBP) = readmemzx(ctx, R(RBP), 8);

    return 0;
}

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