Chapter 5 (Math) missing some details

[m00dawg]

Ideally the relevant info should be transcribed and updated from the C128 doc it links. That doc has the wrong addresses for some things. Likewise the ZP addresses, which are needed for some functions (e.g. AYINT) are not documented (e.g. FACMO and FACLO which in the c128 docs are $63 and $64, but on the X16 they are $C6 and $C7). This requires looking at the basic.sym file after compiling the kernal from source.

VAL_1 also doesn't require the INDEX1 ZP variable on the X16 (according to DesertFish which I was able to confirm in my tests) though the C128 docs indicate that it does.