Endian swapping in QB64pe

[SMcNeill]

For an explanation of the issue you're seeing, (so you can account for it elsewhere in your code), see this:

Code: (Select All)

Print Hex$(&HFFFFFFFF And &HFF)

Print Hex$(&HFFFFFFFF And &HFFFF)

Print Hex$(&HFFFFFFFF And &HFFFFFFFF)

Print

Print &HFF

Print &HFFFF

Print &HFFFFFFFF

Print

Print &HFF~%%

Print &HFFFF~%

Print &HFFFFFFFF~&

Notice how the &H value changes on you? That's because QB64 and basic back in the day, didn't have UNSIGNED values, and also because they wanted to save as much precious memory as possible.

&HH was... an INTEGER, as there was no _BYTE type in QB45. Thus, it represented 255.
&HHHH was... an INTEGER, as integers are 2 bytes and that was the smallest size that could represent those hex digits. As an integer, that made its value -1.
&HHHHHHHH was... an LONG. 4 bytes to hold those 8 hex values. In a signed long, that also made the value -1.

So.... when you AND a value with -1, is that AND with a long or an integer or ????

You run into issues. (As you both have noticed.)

---

Solution?

Take that ambiguity out of your &H type.

IF &HFF is *supposed* to be a LONG, then mark it as one: &HFF&
IF &HFF is *supposed* to be an _INTEGER64, then mark it as one: &HFF&&

Those suffixes there on the end of that &H value is *essential* for what you're doing to work without issues for you. Else you're mixing integers with longs with int64s and... You get FEFOFLOPOP00PS