d2l : convert double to long integer : index : visitInsn()

Description

Pops a two-word double precision floating point number off of the operand stack, converts it into a 64-bit long integer, and pushes the resulting two-word long onto the stack.

Rounding is done using IEEE 754 round-to-nearest mode. The fractional part is lost by rounding towards zero, so (long)-3.14 becomes -3.

If the original double value is NaN, the result is 0. If the value is too large to be represented as an integer, or if it is positive infinity, the result is the largest possible long integer Long.MAX_VALUE. If the value is too small (i.e. a negative value of large magnitude, or negative infinity) then the result is the most negative long integer Long.MIN_VALUE.

In some implementations, this may be coded using the C casting mechanism, e.g.

void d2l(double d, int &l_high, int &l_low)
{
    l_low = (unsigned int)d;
	l_high = (unsigned int)(d / 2**32);
}

where l_low and l_high are respectively the least significant and most significant 32-bit words of the long.

See also

d2i d2f

Stack

Before	After
double-word1	long-word1
double-word2	long-word2
...	...

Bytecode

Type	Description
u1	d2l opcode = 0x8F (143)