Binary to Decimal 32bit signed with PHP

I currently have a Decimal that is coming through as: 4294960896

This is then converted to Binary with this function:

decbin('4294960896')

Which equals: 11111111111111111110011100000000

I then need to take that binary and convert it to the 32bit signed version which should be ‘-6400’

I can’t seem to find any built in functions that support 32bit signed output.

Answer

The hexadecimal representation of the number 4294960896 is FFFFE700h. This should be interpreted as 32 bit signed long. The functions that support such tasks are pack and unpack.

$i64 = 4294960896;

$i32 = unpack('l',pack('V',$i64))[1];
//int(-6400)