/* * (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" #include "LLlex.h" #define arith_sign (1L << (sizeof(arith)*8-1)) void ch3bin(arith *pval, int *pis_uns, int oper, arith val, int is_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; } }