extern "C" Box* pow_i64_i64(i64 lhs, i64 rhs) {
i64 orig_rhs = rhs;
i64 rtn = 1, curpow = lhs;
if (rhs < 0)
return boxFloat(pow_float_float(lhs, rhs));
if (rhs == 0) {
if (lhs < 0)
return boxInt(-1);
return boxInt(1);
}
assert(rhs > 0);
while (rhs) {
if (rhs & 1) {
// TODO: could potentially avoid restarting the entire computation on overflow?
if (__builtin_smull_overflow(rtn, curpow, &rtn))
return longPow(boxLong(lhs), boxLong(orig_rhs));
}
if (__builtin_smull_overflow(curpow, curpow, &curpow))
return longPow(boxLong(lhs), boxLong(orig_rhs));
rhs >>= 1;
}
return boxInt(rtn);
}
OBJ
readNumber(OBJ inStream, char firstChar, int isNegative){
//printf(YEL "\nreadNumber>" RESET);
/*
* TO-DO refactor!
*/
jscheme_int64 *iVal = NULL;
char ch;
OBJ retVal;
// substract the ASCII value of '0' from char to get the actual value between 0 and 9.
jscheme_int64 start = (jscheme_int64) firstChar - '0';
if(isNegative) start *= -1;
iVal = &start;
while( isDigit( ch = nextChar(inStream) )){
//iVal = iVal * 10 + ( (int)ch - '0');
jscheme_int64 ch_val = (jscheme_int64) ch - '0';
if(isNegative){
int mul = __builtin_smull_overflow(*iVal, 10, iVal);
int sub = __builtin_ssubl_overflow(*iVal, ch_val, iVal);
if( mul || sub ){
if(thisIsTheEnd(inStream)){
prompt_on();
}
js_error("readNumber: integer underflow", newInteger(*iVal));
}
}else{
int mul = __builtin_smull_overflow(*iVal, 10, iVal);
int add = __builtin_saddl_overflow(*iVal, ch_val, iVal);
if( mul || add ){
if(thisIsTheEnd(inStream)){
prompt_on();
}
js_error("readNumber: integer overflow", newInteger(*iVal));
}
}
}
unreadChar(inStream, ch);
retVal = newInteger( *iVal );
return retVal;
}
OBJ
builtin_times(int numArgs){
jscheme_int64 *product= NULL;
jscheme_int64 start = 1;
product = &start;
for(int i = 0; i < numArgs; i++){
OBJ theArg = POP();
if( !ISINTEGER(theArg)){
POPN((numArgs - 1) - i);
js_error("(*): non-integer argument", theArg);
}
if(__builtin_smull_overflow(*product,INTVAL(theArg),product)){
// clean stack
POPN((numArgs - 1) - i);
js_error("(*): integer overflow", newInteger(*product));
}
}
return newInteger(*product);
}
extern "C" Box* mul_i64_i64(i64 lhs, i64 rhs) {
i64 result;
if (!__builtin_smull_overflow(lhs, rhs, &result))
return boxInt(result);
return longMul(boxLong(lhs), boxLong(rhs));
}
