The PrintCombatRank (Bank 0) subroutine - Elite on the BBC Micro and NES

       Name: PrintCombatRank                                         [Show more]
       Type: Subroutine
   Category: Status
    Summary: Print the current combat rank
    Context: See this subroutine in context in the source code
 References: This subroutine is called as follows:
             * STATUS calls PrintCombatRank


 This routine is based on part of the STATUS routine from the original source,
 so I have kept the original st3 and st4 labels.


.PrintCombatRank

 LDA #16                ; Print recursive token 130 ("RATING:") followed by
 JSR TT68               ; a colon

 LDA languageNumber     ; If bit 0 of languageNumber is clear then the chosen
 AND #%00000001         ; language is not English, so skip the following
 BEQ P%+5               ; instruction (as the screen has a different layout in
                        ; the other languages)

 JSR TT162              ; Print a space

 LDA TALLY+1            ; Fetch the high byte of the kill tally, and if it is
 BNE st4                ; not zero, then we have more than 256 kills, so jump
                        ; to st4 to work out whether we are Competent,
                        ; Dangerous, Deadly or Elite

                        ; Otherwise we have fewer than 256 kills, so we are one
                        ; of Harmless, Mostly Harmless, Poor, Average or Above
                        ; Average

 TAX                    ; Set X to 0 (as A is 0)

 LDX TALLY              ; Set X to the low byte of the kill tally

 CPX #0                 ; Increment A if X >= 0
 ADC #0

 CPX #2                 ; Increment A if X >= 2
 ADC #0

 CPX #8                 ; Increment A if X >= 8
 ADC #0

 CPX #24                ; Increment A if X >= 24
 ADC #0

 CPX #44                ; Increment A if X >= 44
 ADC #0

 CPX #130               ; Increment A if X >= 130
 ADC #0

 TAX                    ; Set X to A, which will be as follows:
                        ;
                        ;   * 1 (Harmless)        when TALLY = 0 or 1
                        ;
                        ;   * 2 (Mostly Harmless) when TALLY = 2 to 7
                        ;
                        ;   * 3 (Poor)            when TALLY = 8 to 23
                        ;
                        ;   * 4 (Average)         when TALLY = 24 to 43
                        ;
                        ;   * 5 (Above Average)   when TALLY = 44 to 129
                        ;
                        ;   * 6 (Competent)       when TALLY = 130 to 255
                        ;
                        ; Note that the Competent range also covers kill counts
                        ; from 256 to 511, but those are covered by st4 below

.st3

 TXA                    ; Store the combat rank in X on the stack
 PHA

 LDA languageNumber     ; If bits 0 and 2 of languageNumber are clear then the
 AND #%00000101         ; chosen language is not English or French, so skip
 BEQ P%+8               ; the following two instructions (as the screen has a
                        ; different layout in German)

 JSR TT162              ; Print two spaces
 JSR TT162

 PLA                    ; Set A to the combat rank we stored on the stack above

 CLC                    ; Print recursive token 135 + A, which will be in the
 ADC #21                ; range 136 ("HARMLESS") to 144 ("---- E L I T E ----")
 JMP plf                ; followed by a newline, returning from the subroutine
                        ; using a tail call

.st4

                        ; We call this from above with the high byte of the
                        ; kill tally in A, which is non-zero, and want to return
                        ; with the following in X, depending on our rating:
                        ;
                        ;   Competent = 6
                        ;   Dangerous = 7
                        ;   Deadly    = 8
                        ;   Elite     = 9
                        ;
                        ; The high bytes of the top tier ratings are as follows,
                        ; so this a relatively simple calculation:
                        ;
                        ;   Competent       = 1 to 2
                        ;   Dangerous       = 2 to 9
                        ;   Deadly          = 10 to 24
                        ;   Elite           = 25 and up

 LDX #9                 ; Set X to 9 for an Elite rating

 CMP #25                ; If A >= 25, jump to st3 to print out our rating, as we
 BCS st3                ; are Elite

 DEX                    ; Decrement X to 8 for a Deadly rating

 CMP #10                ; If A >= 10, jump to st3 to print out our rating, as we
 BCS st3                ; are Deadly

 DEX                    ; Decrement X to 7 for a Dangerous rating

 CMP #2                 ; If A >= 2, jump to st3 to print out our rating, as we
 BCS st3                ; are Dangerous

 DEX                    ; Decrement X to 6 for a Competent rating

 BNE st3                ; Jump to st3 to print out our rating, as we are
                        ; Competent (this BNE is effectively a JMP as A will
                        ; never be zero)
Status: PrintCombatRank

[NES version, Bank 0]
