charset organization improved + doc

README.md

@@ -12,8 +12,8 @@ You can also make it output useful extra info with:
 $ make debug
 ```
 
-
-## Memory map
+## Developer docs
+### Memory map
 Address               | PRG   | Description
 ----------------------|-------|------------
 ```$0000 - $0001```   | no    | hardware
@@ -30,3 +30,12 @@ Address               | PRG   | Description
 ```$D000 - $DFFF```   | no    | I/O
 ```$E000 - $FFFF```   | no    | Kernal
 
+### Custom charset
+Index           | Description
+----------------|-------------
+```$00 - $1F``` |   A-Z (space first)
+```$20 - $3F``` |   A-Z, reversed (space first)
+```$40 - $4F``` |   hex digits
+```$50 - $5F``` |   hex digits, reversed
+```$60 -    ``` |   game tiles
+

res.org/levels.txt

@@ -7,10 +7,10 @@ x                                      x
 x                                      x
 x                                      x
 x                                      x
-x                                      x
-x                                      x
-x                                      x
-x                                      x
+........................................
+........................................
+........................................
+........................................
 x                                      x
 x                                      x
 x                                      x

src/game.asm

@@ -252,7 +252,7 @@ foodOK:
     ldy #0
     jsr calcTileMem     ; calc food address in memory
     lda (tileMem),y     ; check if memory is empty
-    cmp #$20            ; is there a space?
+    cmp #$00            ; is there a space?
     bne genFood         ; if not, must generate another number
     lda #FOOD_TILE      ; else, just put that fucking piece of food there
     sta (tileMem),y
@@ -312,7 +312,7 @@ checkEndWallHit:
     lda listY,x
     sta calcTileY
     jsr calcTileMem
-    lda #$20            ; just put a space to erase snake tail tile
+    lda #$00            ; just put a space to erase snake tail tile
     sta (tileMem),y
 
 ;    lda #WALL_COLOR

src/gamereset.asm

@@ -4,10 +4,10 @@ gamereset:
     ; Turn MultiColor mode on
     jsr multicolorOn
 
-    ; Upper bar -- fill with reversed spaces, color yellow
+    ; Upper bar -- fill with spaces, color yellow
     ldx #39
 upperbarLoop:
-    lda #$a0    ; reversed color space
+    lda #$0
     sta $400,x
     lda #7
     sta $d800,x

src/initdata.asm

@@ -32,13 +32,13 @@ ST_PAUSE        =	255
 SCREEN_W    =   40
 SCREEN_H    =   24
 ; Snake features
-SNAKE_TILE  =   81
+SNAKE_TILE  =   $60
 SNAKE_COLOR =   13
 ; Food features
-FOOD_TILE   =   90
+FOOD_TILE   =   $61
 FOOD_COLOR  =   10
 ; Wall features
-WALL_TILE   =   91
+WALL_TILE   =   $62
 
 ; Strings
 ; ----------------------------------------------------------------------

src/introreset.asm

@@ -5,7 +5,7 @@ introreset:
 
     ; Clear screen
     ldx #$ff
-    lda #$20
+    lda #$00
 introresetCLS:
     sta $400,x
     sta $500,x

src/subroutines.asm

@@ -58,33 +58,16 @@ printByte:
     lsr
     lsr
     lsr
-    jsr printDigit
+    ora #$40        ; add 64 (see font)
     sta $400,y      ; print msb char
 
     txa             ; Take least significant nibble (use previous copy)
     and #$0f
-    jsr printDigit
-    sta $401,y       ; print lsb char
+    ora #$40        ; add 64 (see font)
+    sta $401,y      ; print lsb char
 
     rts
 
-; Transform a base-36 digit into a Commodore screen code
-; Leave input digit in accumulator; returns output screen code in accumulator
-printDigit:
-    cmp #10
-    bcs printDigitL     ; if it is not a decimal digit, then go to printDigitL
-    clc                 ; it is a decimal digit! Just add `0` (48)
-    adc #48
-    ora #$80            ; reverse color
-    rts
-printDigitL:            ; it is not a decimal digit, then...
-    sec
-    sbc #10             ; take away 10
-    clc
-    adc #1              ; add 1, so you obtain something in [A-F]
-    ora #$80            ; reverse color
-    rts
-
 ; Print null-terminated string on status bar
 ; address of string is given in input using memory location printStatusString
 printStatus:
@@ -94,11 +77,10 @@ printStatusLoop:
     beq printStatusEnd
     cmp #$20
     bne printStatusSkipSpace
-    lda #$60
+    lda #$40 ; space + $40
 printStatusSkipSpace:
     sec
     sbc #$40    ; convert from standard ASCII to Commodore screen code
-    ora #$80    ; reverse color
     sta $413,y
     iny
     jmp printStatusLoop
@@ -114,6 +96,11 @@ printIntro:
 printIntroLoop:
     lda (printIntroString),y    ; get char from string
     beq printIntroEnd           ; if zero, then end (string must be null-terminated)
+    cmp #$20                    ; is space?
+    bne printIntroCheckPunct
+    lda #$0
+    jmp printIntroEndCheck
+printIntroCheckPunct:
     cmp #$40                    ; is char greater or equal to #$40 = #64 = `@' ?
     bcc printIntroEndCheck      ; if not, it is less, thus it must be
                                 ; a full stop, comma, colon or something
@@ -122,6 +109,7 @@ printIntroLoop:
                                 ; otherwise, it is greater than `@`, so must
                                 ; subtract 64 because CBM and its encodings
                                 ; are simply a big shit
+                                ; TODO -- actually must be fixed with new charset
     sec
     sbc #$40
 

util/rlevel.cpp

@@ -7,11 +7,11 @@ void flush(char last, int count) {
     char tile, color;
     switch(last) {
         case 'x':
-            tile = (char)91; color = (char)0x8; break;
+            tile = (char)0x62; color = (char)0x8; break;
         case 'f':
-            tile = (char)90; color = (char)0xa; break;
+            tile = (char)0x61; color = (char)0xa; break;
         default:
-            tile = (char)32; break;
+            tile = (char)0x00; break;
     }
     cout << tile << color << (char)count;
 }