Loader: mvsm

       Name: mvsm                                                    [Show more]
       Type: Subroutine
   Category: Loader
    Summary: Copy 280 bytes in memory
    Context: See this subroutine in context in the source code
 References: This subroutine is called as follows:
             * Elite loader (Part 5 of 7) calls mvsm
             * Elite loader (Part 6 of 7) calls mvsm


 Arguments:

   (A ZP2)              The source address

   ZP(1 0)              The destination address


.mvsm

 LDX #1                 ; Set X = 1 to pass to mvblock so it copies one page of
                        ; data

 JSR mvblock            ; Call mvblock to copy 1 page of data (256 bytes) from
                        ; (A ZP2) to ZP(1 0)

 LDY #23                ; We now want to copy the next 24 bytes to give a total
                        ; of 280 bytes (as 256 + 24 = 280), so set a byte
                        ; counter in Y

 LDX #1                 ; Set X = 1 (though this has no effect, so this is
                        ; presumably left over from development)

.LOOP5new

 LDA (ZP2),Y            ; Copy the Y-th byte of ZP2(1 0) to the Y-th byte of
 STA (ZP),Y             ; ZP(1 0)

 DEY                    ; Decrement the byte counter to point to the next byte

 BPL LOOP5new           ; Loop back to LOOP5new until we have copied all
                        ; 24 bytes

 LDX #0                 ; Set X = 0

 RTS                    ; Return from the subroutine