// Exponent greater than 31 cannot yield 32-bit integers.
// Also, a positive value with an exponent equal to 31 is outside of the
// signed 32-bit integer range.
- __ tst(src1, Operand(HeapNumber::kSignMask));
- __ cmp(scratch, Operand(30), eq); // Executed for positive. If exponent is 30
- // the gt condition will be "correct" and
- // the next instruction will be skipped.
- __ cmp(scratch, Operand(31), ne); // Executed for negative and positive where
- // exponent is not 30.
+ // Another way to put it is that if (exponent - signbit) > 30 then the
+ // number cannot be represented as an int32.
+ Register tmp = dst;
+ __ sub(tmp, scratch, Operand(src1, LSR, 31));
+ __ cmp(tmp, Operand(30));
__ b(gt, not_int32);
// - Bits [21:0] in the mantissa are not null.
__ tst(src2, Operand(0x3fffff));