Continued work - version for C64

C64/gr_basics.asm

@@ -0,0 +1,224 @@
+.IF *>0 ;this is a trick that prevents compiling this file alone
+
+; Basic hardware-dependent graphics routines.
+
+; -----------------------------------------
+.proc unPlot
+; plots a point and saves the plotted byte, reverts the previous plot.
+; -----------------------------------------
+    ldx #0 ; only one pixel
+unPlotAfterX
+    stx WhichUnPlot
+
+    ; first remake the oldie
+    lda oldplotL,x
+    sta oldplot
+    lda oldplotH,x
+    sta oldplot+1
+
+    lda oldply,x
+    tay
+    lda oldora,x
+    sta (oldplot),y
+
+
+    ; is it not out of the screen ????
+    cpw ydraw #screenheight
+    jcc CheckX
+    mwa #0 ydraw
+CheckX
+    cpw xdraw #screenwidth
+    jcs EndOfUnPlot
+MakeUnPlot
+    ; let's count coordinates taken from xdraw and ydraw
+    ;xbyte = xbyte/8
+    lda xdraw+1
+    lsr
+    lda xdraw
+    ror ;just one bit over 256. Max screenwidth = 512!!!
+    lsr
+    lsr
+;---
+    tay
+    ldx WhichUnPlot
+	tya
+    sta oldply,x
+
+    ldx ydraw
+    lda linetableL,x
+    sta xbyte
+    sta oldplot
+    lda linetableH,x
+    sta xbyte+1
+    sta oldplot+1
+
+    lda xdraw
+    and #$7
+    tax
+
+    lda color
+    bne ClearUnPlot
+
+    ;plotting here
+    lda (xbyte),y
+    sta OldOraTemp
+    ora bittable,x
+    sta (xbyte),y
+    bne ContinueUnPlot ; allways <>0
+ClearUnPlot
+    lda (xbyte),y
+    sta OldOraTemp
+    and bittable2,x
+    sta (xbyte),y
+ContinueUnPlot
+    ldx WhichUnPlot
+    lda OldOraTemp
+    sta oldora,x
+    lda oldplot
+    sta oldplotL,x
+    lda oldplot+1
+    sta oldplotH,x
+    ; and now we must solve the problem of several plots
+    ; in one byte
+    ldx #4
+    ldy WhichUnPlot
+LetsCheckOverlapping
+    cpx WhichUnPlot
+    beq SkipThisPlot
+    lda oldplotL,x
+    cmp oldplotL,y
+    bne NotTheSamePlot
+    lda oldplotH,x
+    cmp oldplotH,y
+    bne NotTheSamePlot
+    lda oldply,x
+    cmp oldply,y
+    bne NotTheSamePlot
+    ; the pixel is in the same byte so let's take correct contents
+    lda oldora,x
+    sta oldora,y
+NotTheSamePlot
+SkipThisPlot
+    dex
+    bpl LetsCheckOverlapping
+EndOfUnPlot
+    rts
+.endp
+
+; -----------------------------------------
+.proc plot  ;plot (xdraw, ydraw, color)
+; color == 1 --> put pixel
+; color == 0 --> erase pixel
+; this is one of the most important routines in the whole
+; game. If you are going to speed up the game, start with
+; plot - it is used by every single effect starting from explosions
+; through line drawing and small text output!!!
+; 
+; Optimized by 0xF (Fox) THXXXX!!!
+
+; -----------------------------------------
+    ; is it not over the screen ???
+    cpw ydraw #(screenheight+1); changed for one additional line. cpw ydraw #(screenheight-1)
+    bcs unPlot.EndOfUnPlot ;nearest RTS
+CheckX02
+    cpw xdraw #screenwidth
+    bcs EndOfPlot 
+MakePlot
+    ; let's calculate coordinates from xdraw and ydraw
+
+    ;xbyte = xbyte/8
+    lda xdraw+1
+    lsr
+    lda xdraw
+    ror ;just one bit over 256. Max screenwidth = 512!!!
+    lsr
+    lsr
+    sta xbyte
+    ;---
+    ldx ydraw
+    ldy linetableL,x
+    lda linetableH,x
+    sta xbyte+1
+
+    lda xdraw
+    and #$7
+    tax
+    lda color
+    bne ClearPlot
+
+    lda (xbyte),y
+    ora bittable,x
+    sta (xbyte),y
+EndOfPlot
+    rts
+ClearPlot
+    lda (xbyte),y
+    and bittable2,x
+    sta (xbyte),y
+    rts
+.endp
+
+; -----------------------------------------
+.proc point_plot
+; -----------------------------------------
+    ; checks state of the pixel (coordinates in xdraw and ydraw)
+    ; result is in A (zero or appropriate bit is set)
+
+    ; let's calculate coordinates from xdraw and ydraw
+
+    ;xbyte = xbyte/8
+    lda xdraw+1
+    lsr
+    lda xdraw
+    ror ;just one bit over 256. Max screenwidht = 512!!!
+    lsr
+    lsr
+    sta xbyte
+    ;---
+    ldx ydraw
+    ldy linetableL,x
+    lda linetableH,x
+    sta xbyte+1
+
+    lda xdraw
+    and #$7
+    tax
+
+    lda (xbyte),y
+    eor #$ff
+    and bittable,x
+    rts
+.endp
+
+;--------------------------------------------------
+.proc ClearScreen
+;--------------------------------------------------
+    mwa #display temp
+    ldy #0
+@     lda #$ff
+      sta (temp),y
+      inw temp
+      cpw temp #display+screenheight*screenBytes+1
+    bne @-
+   rts 
+.endp
+
+;--------------------------------------------------
+.proc GenerateLineTable
+
+    mwa #displayC64 temp
+    mwa #linetableL temp2
+    mwa #linetableH modify
+    ldy #0
+@     lda temp
+      sta (temp2),y
+      lda temp+1
+      sta (modify),y
+      adw temp #40
+      iny
+      cpy #screenheight+1
+    bne @-
+	rts
+.endp
+
+.ENDIF

C64/interrupts.asm

@@ -0,0 +1,22 @@
+;	@com.wudsn.ide.asm.mainsourcefile=scorch.asm
+
+    .IF *>0 ;this is a trick that prevents compiling this file alone
+
+
+;--------------------------------------------------
+.macro SetDLI
+;	SetDLI #WORD
+;	Initialises Display List Interrupts
+         LDY # <:1
+         LDX # >:1
+		 jsr _SetDLIproc
+.endm
+.proc _SetDLIproc
+;	LDA #$C0
+;	STY VDSLST
+;	STX VDSLST+1
+;	STA NMIEN
+	rts
+.endp
+
+    .ENDIF

C64/lib/MACRO.ASM

@@ -85,7 +85,7 @@ upstartEnd
     // Set Data Direction for CIA #2, Port A to output
     //
     lda $dd02
-    and #%11111100  // Mask the bits we're interested in.
+    and #%11111100  // Mask the bits were interested in.
     ora #$03        // Set bits 0 and 1.
     sta $dd02