Maths (Arithmetic): MU5

       Name: MU5                                                     [Show more]
       Type: Subroutine
   Category: Maths (Arithmetic)
    Summary: Set K(3 2 1 0) = (A A A A) and clear the C flag
    Context: See this subroutine in context in the source code
 References: This subroutine is called as follows:
             * MULT3 calls MU5
             * DVID3B2 calls via n_store


 In practice this is only called via a BEQ following an AND instruction, in
 which case A = 0, so this routine effectively does this:

   K(3 2 1 0) = 0


 Other entry points:

   n_store              Set K(3 2 1) = (A A A) and clear the C flag


.MU5

                        \ --- Mod: Code removed for Elite-A: ------------------>

\STA K                  \ Set K(3 2 1 0) to (A A A A)
\STA K+1
\STA K+2
\STA K+3

                        \ --- And replaced by: -------------------------------->

 STA K                  \ Set K(3 2 1 0) to (A A A A), starting with the lowest
                        \ byte

.n_store

 STA K+1                \ And then the high bytes
 STA K+2
 STA K+3

                        \ --- End of replacement ------------------------------>

 CLC                    \ Clear the C flag

 RTS                    \ Return from the subroutine