micropython/py/smallint.c

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#include "misc.h"
#include "mpconfig.h"
#include "qstr.h"
#include "obj.h"
bool mp_small_int_mul_overflow(machine_int_t x, machine_int_t y) {
// Check for multiply overflow; see CERT INT32-C
if (x > 0) { // x is positive
if (y > 0) { // x and y are positive
if (x > (MP_SMALL_INT_MAX / y)) {
return true;
}
} else { // x positive, y nonpositive
if (y < (MP_SMALL_INT_MIN / x)) {
return true;
}
} // x positive, y nonpositive
} else { // x is nonpositive
if (y > 0) { // x is nonpositive, y is positive
if (x < (MP_SMALL_INT_MIN / y)) {
return true;
}
} else { // x and y are nonpositive
if (x != 0 && y < (MP_SMALL_INT_MAX / x)) {
return true;
}
} // End if x and y are nonpositive
} // End if x is nonpositive
return false;
}
machine_int_t mp_small_int_modulo(machine_int_t dividend, machine_int_t divisor) {
machine_int_t lsign = (dividend >= 0) ? 1 :-1;
machine_int_t rsign = (divisor >= 0) ? 1 :-1;
dividend %= divisor;
if (lsign != rsign) {
dividend += divisor;
}
return dividend;
}
machine_int_t mp_small_int_floor_divide(machine_int_t num, machine_int_t denom) {
machine_int_t lsign = num > 0 ? 1 : -1;
machine_int_t rsign = denom > 0 ? 1 : -1;
if (lsign == -1) {num *= -1;}
if (rsign == -1) {denom *= -1;}
if (lsign != rsign){
return - ( num + denom - 1) / denom;
} else {
return num / denom;
}
}