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- This file describe tricks that are used throughout the code and might need
- explanation.
-
- or a: Equivalent to "cp 0", but results in a shorter opcode.
-
- xor a: sets A to 0 more efficiently than ld a, 0
-
- and 0xbf: Given a letter in the a-z range, changes it to its uppercase value
- if it's already uppercased, then it stays that way.
-
- Z if almost always used as a success indicator for routines. Set for success,
- Reset for failure. "xor a" (destroys A) and "cp a" (preserves A) are used to
- ensure Z is set. To ensure that it is reset, it's a bit more complicated and
- "unsetZ" routine exists for that, although that in certain circumstances,
- "inc a \ dec a" or "or a" can work.
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