;; This "subroutine" acts as a handler to be able to use variable
;; addresses as a subroutine. You can't JSR to a (variable) in 6502
;; assembly, but you can JSR to a static label, which in turn jumps
;; to the (variable) address. If the routine at that address ends
;; in a RTS, it's handled as the RTS that belongs to the static
;; subroutine. This simulates a variable subroutine, also called a
;; "trampoline" in the NESmaker base scripts.

doTemp16:
    JMP (temp16)

;; Usage:
    LDA low_byte_of_subroutine_address
    STA temp16
    LDA high_byte_of_subroutine_address
    STA temp16+1
    JSR doTemp16



;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; The following adaptation can be used if you need to call a subroutine in a 
;; switchable bank, from another switchable bank. For example, to call
;; "doBank1Subroutine" from bank 2:


;; in the static bank:

doTemp16:
    JMP (temp16)
doTemp16inBankY:
    LDA currentBank
    STA prevBank
    JSR doBankswitchY
    JSR doTemp16
    LDY prevBank
    JSR doBankswitchY
    RTS


;; in Bank 1:

doBank1Subroutine:
    ;; (subroutine stuff here)
    RTS


;; in Bank 2:

    LDA #<doBank1Subroutine
    STA temp16
    LDA #>doBank1Subroutine
    STA temp16+1
    LDY #1
    JSR doTemp16inBankY