kvisc/vm/in/arith.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>

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

IMPL_START_2(sgn)
{
    v1 = (v2 == 0 ? 0 : 
            ((long)v2 < 0 ? (ulong)-1L : 1));
}
IMPL_OUT;

IMPL_START_2(sgnf)
{
    v1 = (long)v2 < 0 ? (ulong)-1L : 1;
}
IMPL_OUT_ZSF;

IMPL_START_1(neg)
{
    v1 = ~v1 + 1;
}
IMPL_OUT;

IMPL_START_1(negf)
{
    if (v1 == 0) flg |= CF;

    else {
        flg &= ~CF;

        if (v1 == LONG_MIN) flg |= OF;
        else flg &= ~OF;
    }

    v1 = ~v1 + 1;
}
IMPL_OUT_ZSF;

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

IMPL_START_1(inc)
{
    v1++;
}
IMPL_OUT;

IMPL_START_1(incf)
{
    if (v1 == LONG_MAX) flg |= OF;
    else flg &= ~OF;

    v1++;
}
IMPL_OUT_ZSF;

IMPL_START_1(dec)
{
    v1--;
}
IMPL_OUT;

IMPL_START_1(decf)
{
    if (v1 == LONG_MIN) flg |= OF;
    else flg &= ~OF;

    v1--;
}
IMPL_OUT_ZSF;

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

IMPL_START_2(add)
{
    v1 += v2;
}
IMPL_OUT;

IMPL_START_2(addf)
{
    if (v1 + v2 < v1) flg |= OF;
    else flg &= ~OF;

    if ( ((v2 > 0) && (v1 > LONG_MAX - v2))
      || ((v2 < 0) && (v1 < LONG_MIN - v2)) )
         flg |= CF;
    else flg &= ~CF;

    v1 += v2;
}
IMPL_OUT_ZSF;

IMPL_START_2(sub)
{
    v1 -= v2;
}
IMPL_OUT;

IMPL_START_2(subf)
{
    COMPARE(v1, v2);
    v1 -= v2;
}
IMPL_OUT;

//
// i_subf but discards result
//
IMPL_START_2(cmp)
{
    COMPARE(v1, v2);
}
IMPL_END;

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

//
// www.codeproject.com/Tips/618570/UInt-Multiplication-Squaring
//
static void multiply(ulong u, ulong v, ulong *hi, ulong *lo)
{
    ulong u1 = (u & 0xffffffff);
    ulong v1 = (v & 0xffffffff);
    ulong t = (u1 * v1);
    ulong w3 = (t & 0xffffffff);
    ulong k = (t >> 32);
    
    u >>= 32;
    t = (u * v1) + k;
    k = (t & 0xffffffff);
    ulong w1 = (t >> 32);
    
    v >>= 32;
    t = (u1 * v) + k;
    k = (t >> 32);
    
    *hi = (u * v) + w1 + k;
    *lo = (t << 32) + w3;
}

IMPL_START_2(mul)
{
    ulong hi;
    multiply(v1, v2, &hi, &v1);
}
IMPL_OUT;

IMPL_START_2(mulf)
{
    ulong hi;

    multiply(v1, v2, &hi, &v1);

    if (hi > 0) {
        flg |= CF;
        flg |= OF;
    }

    else {
        flg &= ~CF;
        flg &= ~OF;
    }
}
IMPL_OUT;

IMPL_START_1(mul2)
{
    multiply(rax, v1, &rdx, &rax);
}
IMPL_END;

IMPL_START_1(mul2f)
{
    multiply(rax, v1, &rdx, &rax);

    if (rdx > 0) {
        flg |= CF;
        flg |= OF;
    }

    else {
        flg &= ~CF;
        flg &= ~OF;
    }
}
IMPL_END;

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

IMPL_START_2(div)
{
    v1 /= v2;
}
IMPL_OUT;

IMPL_START_2(mod)
{
    v1 %= v2;
}
IMPL_OUT;

IMPL_START_1(div2)
{
    rdx = rax % v1;
    rax = rax / v1;
}
IMPL_END;