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https://github.com/ganelson/inform.git
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249 lines
3.4 KiB
C
249 lines
3.4 KiB
C
/*
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* math.c
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*
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* Arithmetic, compare and logical opcodes
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*
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*/
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#include "frotz.h"
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/*
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* z_add, 16bit addition.
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*
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* zargs[0] = first value
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* zargs[1] = second value
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*
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*/
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void z_add (void)
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{
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store ((zword) ((short) zargs[0] + (short) zargs[1]));
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}/* z_add */
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/*
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* z_and, bitwise AND operation.
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*
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* zargs[0] = first value
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* zargs[1] = second value
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*
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*/
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void z_and (void)
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{
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store ((zword) (zargs[0] & zargs[1]));
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}/* z_and */
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/*
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* z_art_shift, arithmetic SHIFT operation.
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*
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* zargs[0] = value
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* zargs[1] = #positions to shift left (positive) or right
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*
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*/
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void z_art_shift (void)
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{
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if ((short) zargs[1] > 0)
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store ((zword) ((short) zargs[0] << (short) zargs[1]));
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else
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store ((zword) ((short) zargs[0] >> - (short) zargs[1]));
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}/* z_art_shift */
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/*
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* z_div, signed 16bit division.
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*
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* zargs[0] = first value
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* zargs[1] = second value
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*
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*/
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void z_div (void)
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{
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if (zargs[1] == 0)
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runtime_error ("Division by zero");
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store ((zword) ((short) zargs[0] / (short) zargs[1]));
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}/* z_div */
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/*
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* z_je, branch if the first value equals any of the following.
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*
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* zargs[0] = first value
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* zargs[1] = second value (optional)
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* ...
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* zargs[3] = fourth value (optional)
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*
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*/
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void z_je (void)
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{
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branch (
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zargc > 1 && (zargs[0] == zargs[1] || (
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zargc > 2 && (zargs[0] == zargs[2] || (
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zargc > 3 && (zargs[0] == zargs[3]))))));
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}/* z_je */
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/*
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* z_jg, branch if the first value is greater than the second.
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*
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* zargs[0] = first value
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* zargs[1] = second value
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*
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*/
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void z_jg (void)
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{
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branch ((short) zargs[0] > (short) zargs[1]);
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}/* z_jg */
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/*
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* z_jl, branch if the first value is less than the second.
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*
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* zargs[0] = first value
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* zargs[1] = second value
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*
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*/
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void z_jl (void)
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{
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branch ((short) zargs[0] < (short) zargs[1]);
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}/* z_jl */
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/*
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* z_jz, branch if value is zero.
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*
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* zargs[0] = value
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*
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*/
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void z_jz (void)
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{
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branch ((short) zargs[0] == 0);
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}/* z_jz */
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/*
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* z_log_shift, logical SHIFT operation.
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*
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* zargs[0] = value
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* zargs[1] = #positions to shift left (positive) or right (negative)
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*
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*/
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void z_log_shift (void)
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{
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if ((short) zargs[1] > 0)
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store ((zword) (zargs[0] << (short) zargs[1]));
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else
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store ((zword) (zargs[0] >> - (short) zargs[1]));
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}/* z_log_shift */
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/*
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* z_mod, remainder after signed 16bit division.
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*
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* zargs[0] = first value
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* zargs[1] = second value
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*
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*/
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void z_mod (void)
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{
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if (zargs[1] == 0)
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runtime_error ("Division by zero");
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store ((zword) ((short) zargs[0] % (short) zargs[1]));
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}/* z_mod */
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/*
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* z_mul, 16bit multiplication.
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*
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* zargs[0] = first value
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* zargs[1] = second value
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*
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*/
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void z_mul (void)
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{
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store ((zword) ((short) zargs[0] * (short) zargs[1]));
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}/* z_mul */
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/*
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* z_not, bitwise NOT operation.
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*
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* zargs[0] = value
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*
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*/
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void z_not (void)
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{
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store ((zword) ~zargs[0]);
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}/* z_not */
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/*
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* z_or, bitwise OR operation.
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*
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* zargs[0] = first value
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* zargs[1] = second value
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*
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*/
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void z_or (void)
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{
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store ((zword) (zargs[0] | zargs[1]));
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}/* z_or */
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/*
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* z_sub, 16bit substraction.
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*
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* zargs[0] = first value
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* zargs[1] = second value
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*
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*/
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void z_sub (void)
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{
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store ((zword) ((short) zargs[0] - (short) zargs[1]));
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}/* z_sub */
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/*
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* z_test, branch if all the flags of a bit mask are set in a value.
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*
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* zargs[0] = value to be examined
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* zargs[1] = bit mask
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*
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*/
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void z_test (void)
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{
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branch ((zargs[0] & zargs[1]) == zargs[1]);
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}/* z_test */
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