Save and load: PrintCommanderName

       Name: PrintCommanderName                                      [Show more]
       Type: Subroutine
   Category: Save and load
    Summary: Print the commander name from the commander file in BUF, with the
             save count added to the end
    Context: See this subroutine in context in the source code
 References: This subroutine is called as follows:
             * PrintNameInMiddle calls PrintCommanderName


 Returns:

   A                    A is preserved


.PrintCommanderName

 PHA                    ; Store the value of A on the stack so we can restore it
                        ; at the end of the subroutine

 LDY #0                 ; We start by printing the commander name from the first
                        ; seven bytes of the commander file at BUF, so set a
                        ; character index in Y so we can loop though the name
                        ; one character at a time

.pnam1

 LDA BUF,Y              ; Set A to the Y-th character from the name at BUF

 JSR DASC_b2            ; Print the character

 INY                    ; Increment the character index in Y

 CPY #7                 ; Loop back until we have printed all seven characters
 BCC pnam1              ; in the BUF buffer from BUF to BUF+6

                        ; Now that the name is printed, we print the save count
                        ; after the end of the name as a one- or two-digit
                        ; decimal value

 LDX #0                 ; Set X = 0 to use as a division counter in the loop
                        ; below

 LDA BUF+7              ; Set A to the byte after the end of the name, which
                        ; contains the save counter in SVC

 AND #%01111111         ; Clear bit 7 of the save counter so we are left with
                        ; the number of saves in A

 SEC                    ; Set the C flag for the subtraction below

.pnam2

 SBC #10                ; Set A = A - 10

 INX                    ; Increment X

 BCS pnam2              ; If the subtraction didn't underflow, jump back to
                        ; pnam2 to subtract another 10

 TAY                    ; By this point X contains the number of whole tens in
                        ; the original number, plus 1 (as that extra one broke
                        ; the subtraction), while A contains the remainder, so
                        ; this instruction sets Y so the following is true:
                        ;
                        ;   SVC = 10 * (X + 1) - (10 - Y)
                        ;       = 10 * (X + 1) + (Y - 10)

 LDA #' '               ; Set A to the ASCII for space

 DEX                    ; Decrement X so this is now true:
                        ;
                        ;   SVC = 10 * X + (Y - 10)

 BEQ pnam3              ; If X = 0 then jump to pnam3 to print a space for the
                        ; first digit of the save count, as it is less than ten

 TXA                    ; Otherwise set A to the ASCII code for the digit in X
 ADC #'0'               ; so we print the correct tens digit for the save
                        ; counter

.pnam3

 JSR DASC_b2            ; Print the character in A to print the first digit of
                        ; the save counter

 TYA                    ; The remainder of the calculation above is Y - 10, so
 CLC                    ; to get the second digit in the value of SVC, we need
 ADC #'0'+10            ; to add 10 to the value in Y, before adding ASCII "0"
                        ; to convert it into a character

 JSR DASC_b2            ; Print the character in A to print the second digit of
                        ; the save counter

 PLA                    ; Restore the value of A that we stored on the stack, so
                        ; A is preserved

 RTS                    ; Return from the subroutine