Drawing the screen: LYN

       Name: LYN                                                     [Show more]
       Type: Subroutine
   Category: Drawing the screen
    Summary: Clear most of a row of pixels
    Context: See this subroutine in context in the source code
 References: This subroutine is called as follows:
             * CLYNS calls LYN


 Set pixels 0-233 to the value in A, starting at the pixel pointed to by SC.


 Arguments:

   A                    The value to store in pixels 1-233 (the only value that
                        is actually used is A = 0, which clears those pixels)


 Returns:

   Y                    Y is set to 0


 Other entry points:

   SC5                  Contains an RTS


.LYN

 LDY #233               \ Set up a counter in Y to count down from pixel 233

.EE2

 STA (SC),Y             \ Store A in the Y-th byte after the address pointed to
                        \ by SC

 DEY                    \ Decrement Y

 BNE EE2                \ Loop back until Y is zero

.SC5

 RTS                    \ Return from the subroutine