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/* math.c - Arithmetic, compare and logical opcodes
* Copyright (c) 1995-1997 Stefan Jokisch
*
* This file is part of Frotz.
*
* Frotz is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* Frotz is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
*/
#include "frotz.h"
/*
* z_add, 16bit addition.
*
* zargs[0] = first value
* zargs[1] = second value
*
*/
void z_add (void)
{
store ((zword) ((short) zargs[0] + (short) zargs[1]));
}/* z_add */
/*
* z_and, bitwise AND operation.
*
* zargs[0] = first value
* zargs[1] = second value
*
*/
void z_and (void)
{
store ((zword) (zargs[0] & zargs[1]));
}/* z_and */
/*
* z_art_shift, arithmetic SHIFT operation.
*
* zargs[0] = value
* zargs[1] = #positions to shift left (positive) or right
*
*/
void z_art_shift (void)
{
if ((short) zargs[1] > 0)
store ((zword) ((short) zargs[0] << (short) zargs[1]));
else
store ((zword) ((short) zargs[0] >> - (short) zargs[1]));
}/* z_art_shift */
/*
* z_div, signed 16bit division.
*
* zargs[0] = first value
* zargs[1] = second value
*
*/
void z_div (void)
{
if (zargs[1] == 0)
runtime_error (ERR_DIV_ZERO);
store ((zword) ((short) zargs[0] / (short) zargs[1]));
}/* z_div */
/*
* z_je, branch if the first value equals any of the following.
*
* zargs[0] = first value
* zargs[1] = second value (optional)
* ...
* zargs[3] = fourth value (optional)
*
*/
void z_je (void)
{
branch (
zargc > 1 && (zargs[0] == zargs[1] || (
zargc > 2 && (zargs[0] == zargs[2] || (
zargc > 3 && (zargs[0] == zargs[3]))))));
}/* z_je */
/*
* z_jg, branch if the first value is greater than the second.
*
* zargs[0] = first value
* zargs[1] = second value
*
*/
void z_jg (void)
{
branch ((short) zargs[0] > (short) zargs[1]);
}/* z_jg */
/*
* z_jl, branch if the first value is less than the second.
*
* zargs[0] = first value
* zargs[1] = second value
*
*/
void z_jl (void)
{
branch ((short) zargs[0] < (short) zargs[1]);
}/* z_jl */
/*
* z_jz, branch if value is zero.
*
* zargs[0] = value
*
*/
void z_jz (void)
{
branch ((short) zargs[0] == 0);
}/* z_jz */
/*
* z_log_shift, logical SHIFT operation.
*
* zargs[0] = value
* zargs[1] = #positions to shift left (positive) or right (negative)
*
*/
void z_log_shift (void)
{
if ((short) zargs[1] > 0)
store ((zword) (zargs[0] << (short) zargs[1]));
else
store ((zword) (zargs[0] >> - (short) zargs[1]));
}/* z_log_shift */
/*
* z_mod, remainder after signed 16bit division.
*
* zargs[0] = first value
* zargs[1] = second value
*
*/
void z_mod (void)
{
if (zargs[1] == 0)
runtime_error (ERR_DIV_ZERO);
store ((zword) ((short) zargs[0] % (short) zargs[1]));
}/* z_mod */
/*
* z_mul, 16bit multiplication.
*
* zargs[0] = first value
* zargs[1] = second value
*
*/
void z_mul (void)
{
store ((zword) ((short) zargs[0] * (short) zargs[1]));
}/* z_mul */
/*
* z_not, bitwise NOT operation.
*
* zargs[0] = value
*
*/
void z_not (void)
{
store ((zword) ~zargs[0]);
}/* z_not */
/*
* z_or, bitwise OR operation.
*
* zargs[0] = first value
* zargs[1] = second value
*
*/
void z_or (void)
{
store ((zword) (zargs[0] | zargs[1]));
}/* z_or */
/*
* z_sub, 16bit substraction.
*
* zargs[0] = first value
* zargs[1] = second value
*
*/
void z_sub (void)
{
store ((zword) ((short) zargs[0] - (short) zargs[1]));
}/* z_sub */
/*
* z_test, branch if all the flags of a bit mask are set in a value.
*
* zargs[0] = value to be examined
* zargs[1] = bit mask
*
*/
void z_test (void)
{
branch ((zargs[0] & zargs[1]) == zargs[1]);
}/* z_test */
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