Equipment: prx

       Name: prx                                                     [Show more]
       Type: Subroutine
   Category: Equipment
    Summary: Return the price of a piece of equipment
    Context: See this subroutine in context in the source code
 References: This subroutine is called as follows:
             * eq calls prx
             * EQSHP calls prx
             * refund calls prx
             * PrintEquipment calls via prx-3
             * eq calls via c


 This routine returns the price of equipment as listed in the table at PRXS.


 Arguments:

   A                    The item number of the piece of equipment (0-13) as
                        shown in the table at PRXS


 Returns:

   (Y X)                The item price in Cr * 10 (Y = high byte, X = low byte)


 Other entry points:

   prx-3                Return the price of the item with number A - 1

   c                    Contains an RTS


 SEC                    ; Decrement A (for when this routine is called via
 SBC #1                 ; prx-3)

.prx

 ASL A                  ; Set Y = A * 2, so it can act as an index into the
 TAY                    ; PRXS table, which has two bytes per entry

 LDX PRXS,Y             ; Fetch the low byte of the price into X

 LDA PRXS+1,Y           ; Fetch the high byte of the price into A and transfer
 TAY                    ; it to X, so the price is now in (Y X)

.c

 RTS                    ; Return from the subroutine

 LDX priceDebug         ; This code is never run, but it looks like it might
 LDA #0                 ; have been used to override the price of equipment
 TAY                    ; during testing, as it sets (Y X) to (0 priceDebug)
 RTS                    ; before returning from the subroutine