Drawing Text Counters

I am using big evil corporations framework for the sega genesis to create my game and got static text and sprites working fine. I am trying to draw arbitrary text such as the player's score, level counters etc. which change over time. I tried using the same functions for static text but they don't work as they require pointers to memory address where the static text is. Here is a link to my source code which also has the framework code. Any assistance in this matter would be greatly appreciated.

Sincerely,

SegaDev

 

Although I have no idea what you're talking about, I just wanted to let you know that your link's dead

 

Something went wrong with the BBCode. Here you go: https://bitbucket.org/SegaDev/scorpion-illuminati

 

You're going to need some ram to store the text in, there are a couple of ways you can do it.

1. Just store the score in ASCII.
dc.b "000000"

And have your update score method do the maths necessary to update the score. Each digit needs an add, compare, branch, subtract/carry to next digit.

2. Keep the score in a dc.l and then convert that to ASCII (either in some work ram or on the stack) using div instructions. Each digit requires a div instruction and they are slow.

A lot of developers use method 1, the code is faster and the score can be as many digits as you want (method 2 is limited to approximately 4 billion). For bonus points only store the score in screen memory (I don't know how practical that is on the genesis).

* I say ASCII but there is no reason that "0" has to be tile 48, you could make "0" be tile 0 for code simplicity.

 

I've replied to your similar post on SpritesMind but here is my hex word version for completion, hopefully it'll help others too.

Code:

ItoA_Hex_w:
   ; Converts a word to hex ASCII
   ; a0 --- In/Out: String address
   ; d0 (w) In: Number to convert

   ; 4 nybbles + 0x + terminator, working backwards
   add.l  #0x7, a0

   ; Zero terminate
   move.b #0x0, -(a0)

   move.w #0x0, d1   ; Char ptr
   move.w #0x3, d2   ; 4 nybbles in a word
   @NybbleLp:
   move.b d0, d3         ; Byte to d3
   andi.b #0x0F, d3      ; Bottom nybble
   cmp.b  #0x9, d3
   ble    @Numeric         ; Branch if in numeric range
   add.b  #(ASCIIAlphaOffset-0xA), d3   ; In alpha range (A - F)
   move.b d3, -(a0)      ; Back to string
   lsr.w  #0x4, d0         ; Next nybble
   dbra   d2, @NybbleLp   ; Loop
   bra    @End
   @Numeric:
   add.b  #ASCIINumericOffset, d3   ; In numeric range (0 - 9)
   move.b d3, -(a0)      ; Back to string
   lsr.w  #0x4, d0         ; Next nybble
   dbra   d2, @NybbleLp   ; Loop

   @End:

   ;0X
   move.b #'X', -(a0)
   move.b #'0', -(a0)

   rts 

As mentioned above, for 10-base decimal you'll need to use divs instead of offsets, and I like the idea of storing '000000' and nudging the count up/down better than all of this anyway. I'll be using that myself

 

I'm getting errors when assembling the source code with that subroutine:

I added the appropriate labels to framework/charmap.asm as stated and still am getting the errors:

Code:

;==============================================================
;  BIG EVIL CORPORATION .co.uk
;==============================================================
;  SEGA Genesis Framework (c) Matt Phillips 2014
;==============================================================
;  charmap.asm - ASCII character map
;==============================================================

ASCIIStart: equ 0x20 ; First ASCII code in table

ASCIIMap:
   dc.b 0x00  ; SPACE (ASCII code 0x20)
   dc.b 0x28  ; ! Exclamation mark
   dc.b 0x2B  ; " Double quotes
   dc.b 0x2E  ; # Hash
   dc.b 0x00  ; UNUSED
   dc.b 0x00  ; UNUSED
   dc.b 0x00  ; UNUSED
   dc.b 0x2C  ; ' Single quote
   dc.b 0x29  ; ( Open parenthesis
   dc.b 0x2A  ; ) Close parenthesis
   dc.b 0x00  ; UNUSED
   dc.b 0x2F  ; + Plus
   dc.b 0x26  ; , Comma
   dc.b 0x30  ; - Minus
   dc.b 0x25  ; . Full stop
   dc.b 0x31  ; / Slash or divide
ASCIINumericOffset
   dc.b 0x1B  ; 0 Zero
   dc.b 0x1C  ; 1 One
   dc.b 0x1D  ; 2 Two
   dc.b 0x1E  ; 3 Three
   dc.b 0x1F  ; 4 Four
   dc.b 0x20  ; 5 Five
   dc.b 0x21  ; 6 Six
   dc.b 0x22  ; 7 Seven
   dc.b 0x23  ; 8 Eight
   dc.b 0x24  ; 9 Nine
   dc.b 0x2D  ; : Colon
   dc.b 0x00  ; UNUSED
   dc.b 0x00  ; UNUSED
   dc.b 0x00  ; UNUSED
   dc.b 0x00  ; UNUSED
   dc.b 0x27  ; ? Question mark
   dc.b 0x00  ; UNUSED
ASCIIAlphaOffset
   dc.b 0x01  ; A
   dc.b 0x02  ; B
   dc.b 0x03  ; C
   dc.b 0x04  ; D
   dc.b 0x05  ; E
   dc.b 0x06  ; F
   dc.b 0x07  ; G
   dc.b 0x08  ; H
   dc.b 0x09  ; I
   dc.b 0x0A  ; J
   dc.b 0x0B  ; K
   dc.b 0x0C  ; L
   dc.b 0x0D  ; M
   dc.b 0x0E  ; N
   dc.b 0x0F  ; O
   dc.b 0x10  ; P
   dc.b 0x11  ; Q
   dc.b 0x12  ; R
   dc.b 0x13  ; S
   dc.b 0x14  ; T
   dc.b 0x15  ; U
   dc.b 0x16  ; V
   dc.b 0x17  ; W
   dc.b 0x18  ; X
   dc.b 0x19  ; Y
   dc.b 0x1A  ; Z (ASCII code 0x5A)

   EVEN

Any assistance in this matter would be greatly appreciated.

Sincerely,

SegaDev