// 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 ((flg & DF) == 0)                                                    \
        R(reg) += len;                                                      \
    else                                                                    \
        R(reg) -= len;

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

static void stos_impl(ctx_t *ctx, acc_t *p1, acc_t *p2, uint len)
{
    ulong reg, val;

    if (p2) {
        DECV(v2, p2);
        reg = p1->reg;
        val = v2;
    }

    else if (p1) {
        DECV(v1, p1);
        reg = RDI;
        val = v1;
    }
    
    else {
        reg = RDI;
        val = rax;
    }

    writemem(ctx, val, R(reg), len);

    STR_MOVE(reg, len);
}

IMPL_START_0(stosb)
{
    stos_impl(ctx, p1, p2, 1);
}
IMPL_END;

IMPL_START_0(stosw)
{
    stos_impl(ctx, p1, p2, 2);
}
IMPL_END;

IMPL_START_0(stosl)
{
    stos_impl(ctx, p1, p2, 4);
}
IMPL_END;

IMPL_START_0(stosq)
{
    stos_impl(ctx, p1, p2, 8);
}
IMPL_END;

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

static void lods_impl(ctx_t *ctx, acc_t *p1, acc_t *p2, uint len)
{
    ulong reg1, reg2;

    if (p2) {
        reg1 = p1->reg;
        reg2 = p2->reg;
    }

    else if (p1) {
        reg1 = p1->reg;
        reg2 = RSI;
    }
    
    else {
        reg1 = RAX;
        reg2 = RSI;
    }

    R(reg1) = readmem(ctx, R(reg2), len);
    
    flg = (R(reg1) == 0 ? flg|ZF : flg&~ZF);

    STR_MOVE(reg2, len);
}

IMPL_START_0(lodsb)
{
    lods_impl(ctx, p1, p2, 1);
}
IMPL_END;

IMPL_START_0(lodsw)
{
    lods_impl(ctx, p1, p2, 2);
}
IMPL_END;

IMPL_START_0(lodsl)
{
    lods_impl(ctx, p1, p2, 4);
}
IMPL_END;

IMPL_START_0(lodsq)
{
    lods_impl(ctx, p1, p2, 8);
}
IMPL_END;

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

static void scas_impl(ctx_t *ctx, acc_t *p1, acc_t *p2, uint len)
{
    ulong reg, val;

    if (p2) {
        DECV(v2, p2);
        reg = p1->reg;
        val = v2;
    }

    else if (p1) {
        DECV(v1, p1);
        reg = RDI;
        val = v1;
    }

    else {
        reg = RDI;
        val = rax;
    }

    ulong x = readmem(ctx, R(reg), len);
    COMPARE(x, val);

    STR_MOVE(reg, len);
}

IMPL_START_0(scasb)
{
    scas_impl(ctx, p1, p2, 1);
}
IMPL_END;

IMPL_START_0(scasw)
{
    scas_impl(ctx, p1, p2, 2);
}
IMPL_END;

IMPL_START_0(scasl)
{
    scas_impl(ctx, p1, p2, 4);
}
IMPL_END;

IMPL_START_0(scasq)
{
    scas_impl(ctx, p1, p2, 8);
}
IMPL_END;

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

static void scazs_impl(ctx_t *ctx, acc_t *p1, uint len)
{
    ulong reg;

    if (p1)
        reg = p1->reg;
    else
        reg = RDI;

    ulong x = readmem(ctx, R(reg), len);
    COMPARE(x, 0);

    if (!(flg&ZF)) {
        STR_MOVE(reg, len);
    }
}

IMPL_START_0(scazsb)
{
    scazs_impl(ctx, p1, 1);
}
IMPL_END;

IMPL_START_0(scazsw)
{
    scazs_impl(ctx, p1, 2);
}
IMPL_END;

IMPL_START_0(scazsl)
{
    scazs_impl(ctx, p1, 4);
}
IMPL_END;

IMPL_START_0(scazsq)
{
    scazs_impl(ctx, p1, 8);
}
IMPL_END;

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

static void cmps_impl(ctx_t *ctx, acc_t *p1, acc_t *p2, uint len)
{
    ulong reg1, reg2;

    if (p2) {
        reg1 = p1->reg;
        reg2 = p2->reg;
    }

    else if (p1) {
        reg1 = RDI;
        reg2 = p1->reg;
    }

    else {
        reg1 = RDI;
        reg2 = RSI;
    }

    ulong x1 = readmem(ctx, R(reg1), len);
    ulong x2 = readmem(ctx, R(reg2), len);

    COMPARE(x1, x2);

    STR_MOVE(reg1, len);
    STR_MOVE(reg2, len);
}

IMPL_START_0(cmpsb)
{
    cmps_impl(ctx, p1, p2, 1);
}
IMPL_END;

IMPL_START_0(cmpsw)
{
    cmps_impl(ctx, p1, p2, 2);
}
IMPL_END;

IMPL_START_0(cmpsl)
{
    cmps_impl(ctx, p1, p2, 4);
}
IMPL_END;

IMPL_START_0(cmpsq)
{
    cmps_impl(ctx, p1, p2, 8);
}
IMPL_END;

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

static void cmpzs_impl(ctx_t *ctx, acc_t *p1, acc_t *p2, uint len)
{
    ulong reg1, reg2;

    if (p2) {
        reg1 = p1->reg;
        reg2 = p2->reg;
    }

    else if (p1) {
        reg1 = RDI;
        reg2 = p1->reg;
    }

    else {
        reg1 = RDI;
        reg2 = RSI;
    }

    ulong x1 = readmem(ctx, R(reg1), len);
    ulong x2 = readmem(ctx, R(reg2), len);

    COMPARE(x1, x2);

    if (!x1 && !x2)
        flg &= ~ZF;

    STR_MOVE(reg1, len);
    STR_MOVE(reg2, len);
}

IMPL_START_0(cmpzsb)
{
    cmpzs_impl(ctx, p1, p2, 1);
}
IMPL_END;

IMPL_START_0(cmpzsw)
{
    cmpzs_impl(ctx, p1, p2, 2);
}
IMPL_END;

IMPL_START_0(cmpzsl)
{
    cmpzs_impl(ctx, p1, p2, 4);
}
IMPL_END;

IMPL_START_0(cmpzsq)
{
    cmpzs_impl(ctx, p1, p2, 8);
}
IMPL_END;

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

static void movs_impl(ctx_t *ctx, acc_t *p1, acc_t *p2, uint len)
{
    ulong reg1, reg2;

    if (p2) {
        reg1 = p1->reg;
        reg2 = p2->reg;
    }

    else if (p1) {
        reg1 = RDI;
        reg2 = p1->reg;
    }

    else {
        reg1 = RDI;
        reg2 = RSI;
    }

    ulong x = readmem(ctx, R(reg2), len);
    writemem(ctx, x, R(reg1), len);

    flg = (x == 0 ? flg|ZF : flg&~ZF);

    STR_MOVE(reg1, len);
    STR_MOVE(reg2, len);
}

IMPL_START_0(movsb)
{
    movs_impl(ctx, p1, p2, 1);
}
IMPL_END;

IMPL_START_0(movsw)
{
    movs_impl(ctx, p1, p2, 2);
}
IMPL_END;

IMPL_START_0(movsl)
{
    movs_impl(ctx, p1, p2, 4);
}
IMPL_END;

IMPL_START_0(movsq)
{
    movs_impl(ctx, p1, p2, 8);
}
IMPL_END;

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