optimized cx16 txt screen functions to use VERA autoincrement

compiler/res/prog8lib/c64/textio.p8

@@ -16,11 +16,8 @@ const ubyte DEFAULT_WIDTH = 40
 const ubyte DEFAULT_HEIGHT = 25
 
 
-asmsub  clear_screen() {
+sub  clear_screen() {
-    %asm {{
+    clear_screenchars(' ')
-        lda  #' '
-        jmp  clear_screenchars
-    }}
 }
 
 asmsub  fill_screen (ubyte char @ A, ubyte charcolor @ Y) clobbers(A)  {

compiler/res/prog8lib/cx16/textio.p8

@@ -16,74 +16,78 @@ const ubyte DEFAULT_HEIGHT = 60
 
 
 sub  clear_screen() {
-    c64.CHROUT(147)         ; clear screen (spaces)
+    clear_screenchars(' ')
 }
 
 asmsub  fill_screen (ubyte char @ A, ubyte txtcolor @ Y) clobbers(A)  {
 	; ---- fill the character screen with the given fill character and character color.
-	; TODO this can be done more efficiently with the VERA auto increment mode?
 	%asm {{
-        sta  P8ZP_SCRATCH_W1        ; fillchar
+	    sty  _ly+1
-        sty  P8ZP_SCRATCH_W1+1      ; textcolor
         phx
+        pha
         jsr  c64.SCREEN             ; get dimensions in X/Y
-        dex
-        dey
         txa
-        asl  a
+        lsr  a
-        adc  #1
+        lsr  a
-        sta  P8ZP_SCRATCH_B1
+        sta  _lx+1
--       ldx  P8ZP_SCRATCH_B1
+        lda  #%00010000
--       stz  cx16.VERA_ADDR_H
+        sta  cx16.VERA_ADDR_H       ; enable auto increment by 1, bank 0.
-        stx  cx16.VERA_ADDR_L
+        stz  cx16.VERA_ADDR_L       ; start at (0,0)
-        sty  cx16.VERA_ADDR_M
+        stz  cx16.VERA_ADDR_M
-        lda  cx16.VERA_DATA0
+        pla
-        and  #$f0
+_lx     ldx  #0                     ; modified
-        ora  P8ZP_SCRATCH_W1+1
+        phy
+_ly     ldy  #1                     ; modified
+-       sta  cx16.VERA_DATA0
+        sty  cx16.VERA_DATA0
         sta  cx16.VERA_DATA0
-        dex
+        sty  cx16.VERA_DATA0
-        stz  cx16.VERA_ADDR_H
-        stx  cx16.VERA_ADDR_L
-        sty  cx16.VERA_ADDR_M
-        lda  P8ZP_SCRATCH_W1
         sta  cx16.VERA_DATA0
+        sty  cx16.VERA_DATA0
+        sta  cx16.VERA_DATA0
+        sty  cx16.VERA_DATA0
         dex
-        cpx  #255
         bne  -
+        ply
         dey
-        bpl  --
+        beq  +
-        plx
+        stz  cx16.VERA_ADDR_L
+        inc  cx16.VERA_ADDR_M       ; next line
+        bra  _lx
++       plx
         rts
-    }}
+        }}
-
 }
 
 asmsub  clear_screenchars (ubyte char @ A) clobbers(Y)  {
 	; ---- clear the character screen with the given fill character (leaves colors)
 	;      (assumes screen matrix is at the default address)
-	; TODO this can be done more efficiently with the VERA auto increment mode?
 	%asm {{
         phx
         pha
         jsr  c64.SCREEN             ; get dimensions in X/Y
-        dex
-        dey
         txa
-        asl  a
+        lsr  a
-        sta  _mod+1
+        lsr  a
+        sta  _lx+1
+        lda  #%00100000
+        sta  cx16.VERA_ADDR_H       ; enable auto increment by 2, bank 0.
+        stz  cx16.VERA_ADDR_L       ; start at (0,0)
+        stz  cx16.VERA_ADDR_M
         pla
-_mod    ldx  #0                     ; modified
+_lx     ldx  #0                     ; modified
--       stz  cx16.VERA_ADDR_H
+-       sta  cx16.VERA_DATA0
-        stx  cx16.VERA_ADDR_L
+        sta  cx16.VERA_DATA0
-        sty  cx16.VERA_ADDR_M
+        sta  cx16.VERA_DATA0
         sta  cx16.VERA_DATA0
         dex
-        dex
-        cpx  #-2
         bne  -
         dey
-        bpl  _mod
+        beq  +
-        plx
+        stz  cx16.VERA_ADDR_L
+        inc  cx16.VERA_ADDR_M       ; next line
+        bra  _lx
++       plx
         rts
         }}
 }
@@ -91,30 +95,34 @@ _mod    ldx  #0                     ; modified
 asmsub  clear_screencolors (ubyte scrcolor @ A) clobbers(Y)  {
 	; ---- clear the character screen colors with the given color (leaves characters).
 	;      (assumes color matrix is at the default address)
-	; TODO this can be done more efficiently with the VERA auto increment mode?
 	%asm {{
         phx
-        pha
+        sta  _la+1
         jsr  c64.SCREEN             ; get dimensions in X/Y
-        dex
-        dey
         txa
-        asl  a
+        lsr  a
-        ina
+        lsr  a
-        sta  _mod+1
+        sta  _lx+1
-        pla
+        lda  #%00100000
-_mod    ldx  #0                     ; modified
+        sta  cx16.VERA_ADDR_H       ; enable auto increment by 2, bank 0.
--       stz  cx16.VERA_ADDR_H
+        lda  #1
-        stx  cx16.VERA_ADDR_L
+        sta  cx16.VERA_ADDR_L       ; start at (1,0)
-        sty  cx16.VERA_ADDR_M
+        stz  cx16.VERA_ADDR_M
+_lx     ldx  #0                     ; modified
+_la     lda  #0                     ; modified
+-       sta  cx16.VERA_DATA0
+        sta  cx16.VERA_DATA0
+        sta  cx16.VERA_DATA0
         sta  cx16.VERA_DATA0
         dex
-        dex
-        cpx  #-1
         bne  -
         dey
-        bpl  _mod
+        beq  +
-        plx
+        lda  #1
+        sta  cx16.VERA_ADDR_L
+        inc  cx16.VERA_ADDR_M       ; next line
+        bra  _lx
++       plx
         rts
         }}
 }

examples/test.p8

@@ -1,7 +1,6 @@
 %import syslib
 ; %import graphics
 %import textio
-%import floats
 %zeropage basicsafe
 
 
@@ -9,7 +8,17 @@ main {
 
     sub start()  {
 
-        txt.clear_screenchars('*')
+        ; 40 x 25
+        ; 80 x 60
+        txt.fill_screen('*', 8)
+
+        txt.clear_screen()
+
+        txt.print_ub(txt.width())
+        txt.chrout('\n')
+        txt.print_ub(txt.height())
+        txt.chrout('\n')
+
         ubyte i
         repeat {
             txt.clear_screencolors(i)