Number Entry

The left part of the calculator is for number entry.  The top half represents the Y element of the stack, a number already entered.  The bottom half represents the X element and is the place where new numbers are entered.

There are eight places where you can enter digits or characters:  long, UInt32, Fixed, Octal, Hi-Double, Fract, Hex, and OSType.  These types should be familiar to Macintosh programmers.  Except for Hi-Double all of them are 32-bit values.  Hi-Double means the high 32 bits of an 8-byte double.  These are the most significant bits in a double so it is interesting to see how floating point numbers are represented.  (Note that the lower half of the double is always left as zero so there is a loss of accuracy.)  Whichever edit field is active controls the numeric format of the stack.