173 lines
3.5 KiB
C
173 lines
3.5 KiB
C
/*
|
|
* (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
|
|
* See the copyright notice in the ACK home directory, in the file "Copyright".
|
|
*/
|
|
/* $Id$ */
|
|
/* EVALUATION OF BINARY OPERATORS */
|
|
|
|
#include "Lpars.h"
|
|
#include "arith.h"
|
|
|
|
#define arith_sign (1L << (sizeof(arith)*8-1))
|
|
|
|
ch3bin(pval, pis_uns, oper, val, is_uns)
|
|
register arith *pval, val;
|
|
int oper, is_uns, *pis_uns;
|
|
{
|
|
if (is_uns) *pis_uns = 1;
|
|
switch (oper) {
|
|
case '/':
|
|
if (val == 0) {
|
|
error("/ by 0");
|
|
break;
|
|
}
|
|
if (*pis_uns) {
|
|
#ifdef UNSIGNED_ARITH
|
|
*pval /= (UNSIGNED_ARITH) val;
|
|
#else
|
|
/* this is more of a problem than you might
|
|
think on C compilers which do not have
|
|
unsigned arith (== long (probably)).
|
|
*/
|
|
if (val & arith_sign) {/* val > max_arith */
|
|
*pval = ! (*pval >= 0 || *pval < val);
|
|
/* this is the unsigned test
|
|
*pval < val for val > max_arith
|
|
*/
|
|
}
|
|
else { /* val <= max_arith */
|
|
arith half, bit, hdiv, hrem, rem;
|
|
|
|
half = (*pval >> 1) & ~arith_sign;
|
|
bit = *pval & 01;
|
|
/* now *pval == 2 * half + bit
|
|
and half <= max_arith
|
|
and bit <= max_arith
|
|
*/
|
|
hdiv = half / val;
|
|
hrem = half % val;
|
|
rem = 2 * hrem + bit;
|
|
*pval = 2 * hdiv + (rem < 0 || rem >= val);
|
|
/* that is the unsigned compare
|
|
rem >= val for val <= max_arith
|
|
*/
|
|
}
|
|
#endif
|
|
}
|
|
else {
|
|
*pval = *pval / val;
|
|
}
|
|
break;
|
|
case '%':
|
|
if (val == 0) {
|
|
error("%% by 0");
|
|
break;
|
|
}
|
|
if (*pis_uns) {
|
|
#ifdef UNSIGNED_ARITH
|
|
*pval %= (UNSIGNED_ARITH) val;
|
|
#else
|
|
if (val & arith_sign) {/* val > max_arith */
|
|
*pval = (*pval >= 0 || *pval < val) ? *pval : *pval - val;
|
|
/* this is the unsigned test
|
|
*pval < val for val > max_arith
|
|
*/
|
|
}
|
|
else { /* val <= max_arith */
|
|
arith half, bit, hrem, rem;
|
|
|
|
half = (*pval >> 1) & ~arith_sign;
|
|
bit = *pval & 01;
|
|
/* now *pval == 2 * half + bit
|
|
and half <= max_arith
|
|
and bit <= max_arith
|
|
*/
|
|
hrem = half % val;
|
|
rem = 2 * hrem + bit;
|
|
*pval = (rem < 0 || rem >= val) ? rem - val : rem;
|
|
}
|
|
#endif
|
|
}
|
|
else {
|
|
*pval = *pval % val;
|
|
}
|
|
break;
|
|
case '*':
|
|
*pval = *pval * val;
|
|
break;
|
|
case '+':
|
|
*pval = *pval + val;
|
|
break;
|
|
case '-':
|
|
*pval = *pval - val;
|
|
break;
|
|
case LEFT:
|
|
*pval = *pval << val;
|
|
break;
|
|
case RIGHT:
|
|
if (val == 0) break;
|
|
if (*pis_uns) {
|
|
*pval = (*pval >> 1) & ~arith_sign;
|
|
*pval = *pval >> (val - 1);
|
|
}
|
|
else *pval = *pval >> val;
|
|
break;
|
|
case '<':
|
|
{ arith tmp = *pval; *pval = val; val = tmp; }
|
|
/* fall through */
|
|
case '>':
|
|
if (*pis_uns) {
|
|
#ifdef UNSIGNED_ARITH
|
|
*pval = (UNSIGNED_ARITH) *pval > (UNSIGNED_ARITH) val;
|
|
#else
|
|
*pval = (*pval & arith_sign ?
|
|
(val & arith_sign ? *pval > val : 1) :
|
|
(val & arith_sign ? 0 : *pval > val)
|
|
);
|
|
#endif
|
|
}
|
|
else *pval = (*pval > val);
|
|
break;
|
|
case LESSEQ:
|
|
{ arith tmp = *pval; *pval = val; val = tmp; }
|
|
/* fall through */
|
|
case GREATEREQ:
|
|
if (*pis_uns) {
|
|
#ifdef UNSIGNED_ARITH
|
|
*pval = (UNSIGNED_ARITH) *pval >= (UNSIGNED_ARITH) val;
|
|
#else
|
|
*pval = (*pval & arith_sign ?
|
|
(val & arith_sign ? *pval >= val : 1) :
|
|
(val & arith_sign ? 0 : *pval >= val)
|
|
);
|
|
#endif
|
|
}
|
|
else *pval = (*pval >= val);
|
|
break;
|
|
case EQUAL:
|
|
*pval = (*pval == val);
|
|
break;
|
|
case NOTEQUAL:
|
|
*pval = (*pval != val);
|
|
break;
|
|
case '&':
|
|
*pval = *pval & val;
|
|
break;
|
|
case '^':
|
|
*pval = *pval ^ val;
|
|
break;
|
|
case '|':
|
|
*pval = *pval | val;
|
|
break;
|
|
case AND:
|
|
*pval = (*pval && val);
|
|
break;
|
|
case OR:
|
|
*pval = (*pval || val);
|
|
break;
|
|
case ',':
|
|
*pis_uns = is_uns;
|
|
*pval = val;
|
|
break;
|
|
}
|
|
}
|