first commit

graphics.s

@@ -0,0 +1,177 @@
+; Graphics Module
+; ---------------------------------------------------------------------------
+
+    INCDIR  "c:/Users/capitano/Documents/giochino/"
+    INCLUDE "custom.i"
+    
+    ; XDEF    InitGraphics
+    ; XDEF    CopperList
+    ; XDEF    Bitplane1
+    ; XDEF    ClearScreen
+    ; XDEF    DrawText
+    ; XDEF    DrawChar
+
+    ; XREF    Font8x8
+
+    ; SECTION Code,CODE_C
+
+InitGraphics:
+    lea     CUSTOM,a6
+
+    ; 1. Setup Bitplanes
+    move.w  #$1200,BPLCON0(a6)  ; 1 Bitplane, Color on
+    move.w  #0,BPLCON1(a6)      ; Scroll 0
+    move.w  #0,BPLCON2(a6)      ; Priority 0
+    move.w  #0,BPL1MOD(a6)      ; Modulo 0
+    
+    ; Setup Display Window
+    move.w  #$2c81,DIWSTRT(a6)
+    move.w  #$2cc1,DIWSTOP(a6)
+    move.w  #$0038,DDFSTRT(a6)
+    move.w  #$00d0,DDFSTOP(a6)
+
+    ; 2. Setup Copper List
+    lea     CopperList,a0
+    move.l  a0,COP1LCH(a6)
+    move.w  #0,COPJMP1(a6)
+
+    ; 3. Setup Bitplane Pointers
+    lea     Bitplane1,a1
+    move.l  a1,d0
+    lea     CopperBplPtr,a0
+    swap    d0
+    move.w  d0,2(a0)
+    swap    d0
+    move.w  d0,6(a0)
+
+    ; 4. Clear Screen
+    bsr     ClearScreen
+
+    rts
+
+ClearScreen:
+    lea     Bitplane1,a0
+    move.w  #(40*256)/4-1,d0 ; Longwords
+.loop:
+    move.l  #0,(a0)+
+    dbf     d0,.loop
+    rts
+
+; DrawText
+; d0 = X, d1 = Y, a0 = String
+DrawText:
+    movem.l d0-d3/a0-a2,-(sp)
+    
+    ; d0 = Initial X (keep in d3 for CR)
+    move.w  d0,d3
+    
+    ; Initial Setup
+    bsr     .calcAddr
+
+.charLoop:
+    move.b  (a0)+,d2    ; Get char
+    beq.s   .done       ; Null terminator?
+
+    cmp.b   #10,d2      ; Newline (LF)?
+    beq.s   .newline
+    cmp.b   #13,d2      ; CR?
+    beq.s   .carriageReturn
+
+    sub.b   #32,d2      ; ASCII adjustment
+    ext.w   d2
+    
+    ; Get font address
+    lea     Font8x8,a2
+    lsl.w   #3,d2       ; * 8
+    add.w   d2,a2
+
+    ; Draw 8 lines of the char
+    move.b  (a2)+,(a1)
+    move.b  (a2)+,40(a1)
+    move.b  (a2)+,80(a1)
+    move.b  (a2)+,120(a1)
+    move.b  (a2)+,160(a1)
+    move.b  (a2)+,200(a1)
+    move.b  (a2)+,240(a1)
+    move.b  (a2)+,280(a1)
+
+    addq.w  #1,a1       ; Next char pos
+    bra.s   .charLoop
+
+.newline:
+    addq.w  #1,d1       ; Increment Y (lines)
+    bsr     .calcAddr   ; Recalculate address (Resets X to d3)
+    bra.s   .charLoop
+
+.carriageReturn:
+    ; Just reset X to d3, keep Y
+    bsr     .calcAddr
+    bra.s   .charLoop
+
+.done:
+    movem.l (sp)+,d0-d3/a0-a2
+    rts
+
+.calcAddr:
+    lea     Bitplane1,a1
+    move.l  d1,d4       ; Copy Y
+    mulu    #320,d4     ; Y * 320
+    add.l   d4,a1
+    add.w   d3,a1       ; Add Initial X
+    rts
+
+; DrawChar
+; d2 = Char code, d0 = X, d1 = Y
+DrawChar:
+    movem.l d0-d3/a0-a2,-(sp)
+    lea     Bitplane1,a1
+    mulu    #320,d1
+    add.l   d1,a1
+    add.w   d0,a1
+
+    sub.b   #32,d2
+    ext.w   d2
+    lea     Font8x8,a2
+    lsl.w   #3,d2
+    add.w   d2,a2
+
+    move.b  (a2)+,(a1)
+    move.b  (a2)+,40(a1)
+    move.b  (a2)+,80(a1)
+    move.b  (a2)+,120(a1)
+    move.b  (a2)+,160(a1)
+    move.b  (a2)+,200(a1)
+    move.b  (a2)+,240(a1)
+    move.b  (a2)+,280(a1)
+
+    movem.l (sp)+,d0-d3/a0-a2
+    rts
+
+    ; SECTION Data,DATA_C
+
+    CNOP 0,4
+CopperList:
+    DC.W    COLOR00, $0333  ; Background
+    DC.W    COLOR01, $0FF0  ; Text
+
+CopperBplPtr:
+    DC.W    BPL1PTH, $0000
+    DC.W    BPL1PTL, $0000
+
+    ; Desk Top
+    DC.W    $2c07, $FFFE
+    DC.W    COLOR00, $0642
+
+    ; Monitor Area (Lines 80-200 approx)
+    DC.W    $5007, $FFFE
+    DC.W    COLOR00, $0000
+
+    ; Desk Bottom
+    DC.W    $D007, $FFFE
+    DC.W    COLOR00, $0642
+
+    DC.W    $FFFF, $FFFE
+
+    CNOP 0,4
+Bitplane1:
+    DS.B    40*256