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⌂ ∞ ▽ Elite on the BBC Micro and NES

Version analysis of MLS2

This code appears in the following versions (click to see it in the source code):

Code variations between these versions are shown below.

       Name: MLS2
       Type: Subroutine
   Category: Maths (Arithmetic)
    Summary: Calculate (S R) = XX(1 0) and (A P) = A * ALP1



 Calculate the following:

   (S R) = XX(1 0)

   (A P) = A * ALP1

 where ALP1 is the magnitude of the current roll angle alpha, in the range
 0-31.



.MLS2

 LDX XX                 \ Set (S R) = XX(1 0), starting with the low bytes
 STX R

 LDX XX+1               \ And then doing the high bytes
 STX S

Code variation 1 of 1Other (e.g. bug fix, optimisation)

There's an extra bit of code in the disc version of the MLS2 routine that has no effect.

Tap on a block to expand it, and tap it again to revert.

Cassette, Flight, 6502SP, Master, Electron
Docked
                        \ Fall through into MLS1 to calculate (A P) = A * ALP1

 LDX ALP1               \ This repeats the first two instructions of MLS1, which
 STX P                  \ is presumably unintentional (though it has no effect)

                        \ Fall through into SQUA to calculate (A P) = A * ALP1