.import popa, _gotoxy
.import xsize
.import soft80_kplot
- .import __bgcolor
+ .import __bgcolor, __textcolor
.importzp tmp4,tmp3
jmp _back
;-------------------------------------------------------------------------------
+; optional "color voodoo". the problem is that each 8x8 cell can only contain
+; two colors, one of which is used for the background color, so two characters
+; have to share the same text color.
+;
+; - in a cell that contains two spaces, both the color ram and the text color
+; in vram contain the background color
+;
+; - in a cell that contains one character, its text color goes into vram. the
+; color ram contains the background color.
+;
+; - in a cell that contains two characters, the color of the left character goes
+; to vram (and is shared by both for display). the "would be" color of the
+; right character goes to color ram as a reminder and can be restored when one
+; of the two characters is cleared by a space.
.if SOFT80COLORVOODOO = 1
-;--- start color vodoo
; remove color from cell, called before putting a "space" character to the bitmap
-; y unmodified
+;
+; __ -> __ -
+; _A -> _A -
+; B_ -> B_ -
+; _A -> __ vram = bgcol
+; B_ -> __ vram = bgcol
+; BA -> _A vram = colram, colram = bgcol
+; BA -> B_ colram = bgcol
+;
+; in: x must be $34
+; y must be $00
+; out: y = $00
remcolor:
;ldy #$00 ; is still $00
lda (CRAM_PTR),y ; vram (textcolor)
and #$0f
cmp __bgcolor
- jeq @l2b ; yes, vram==bgcolor
+ beq @sk1 ; yes, vram==bgcolor
; now check if the textcolor in color ram is equal the background color,
; if yes then there is only one (visible) character in the current cell
- inc $01
+ inc $01 ; $35
lda (CRAM_PTR),y ; colram (2nd textcolor)
- stx $01 ;$34
+ stx $01 ; $34
and #$0f
cmp __bgcolor
- beq @l2s ; yes, colram==bgcolor
+ beq @sk2 ; yes, colram==bgcolor
; two characters in the current cell, of which one will get removed
;lda (CRAM_PTR),y ; colram
;stx $01 ;$34
;and #$0f
+ sta tmp3 ; A contains colram
- ; move 2nd text color to vram
- sta tmp3
+ lda CURS_X
+ and #$01
+ bne @sk3
+
+ ; vram = colram
lda (CRAM_PTR),y ; vram
and #$f0
ora tmp3
sta (CRAM_PTR),y ; vram
-
+@sk3:
; colram = bgcolor
lda __bgcolor
- inc $01
+ inc $01 ; $35
sta (CRAM_PTR),y ; colram
- stx $01 ;$34
+ stx $01 ; $34
- jmp @l2b
+ rts
-@l2s:
+@sk2:
; colram is bgcolor
; => only one char in cell used
jsr soft80_checkchar
- bcc @l2b ; space at current position
+ bcc @sk1 ; space at current position
; vram (textcolor) = bgcolor
lda (CRAM_PTR),y ; vram
and #$f0
ora __bgcolor
sta (CRAM_PTR),y ; vram
-@l2b:
+@sk1:
rts
; put color to cell
-; in: $01 is $34 (RAM under I/O) when entering
-; y must be $00
-; out: y = $00
+;
+; __ -> _A vram = textcol
+; __ -> B_ vram = textcol
+; _A -> BA colram = vram, vram = textcol
+; B_ -> BA colram = textcol
+;
+; _A -> _C vram = textcol
+; B_ -> C_ vram = textcol
+; BA -> BC colram = textcol
+; BA -> CA vram = textcol
+;
+; in: $01 is $34 (RAM under I/O) when entering
+; x must be $34
+; y must be $00
+; out: x = $34
+; y = $00
soft80_putcolor:
;ldy #$00 ; is still $00
lda (CRAM_PTR),y ; vram
and #$0f
cmp __bgcolor
- beq @l2s ; vram==bgcolor => first char in cell
+ beq @sk1 ; vram==bgcolor => first char in cell
; vram!=bgcolor => second char in cell
- inc $01 ;$35
+ inc $01 ; $35
lda (CRAM_PTR),y ; colram
- stx $01 ;$34
+ stx $01 ; $34
and #$0f
cmp __bgcolor
- bne @l2s ; colram!=bgcolor
+ beq @l2s ; colram==bgcolor -> second char in cell
- ; colram==bgcolor => second char in cell or overwrite 1st char
+ ; botch characters in the cell are used
+ lda CURS_X
+ and #$01
+ bne @sk2 ; jump if odd xpos
+
+ ; vram = textcol
+ lda CHARCOLOR
+ sta (CRAM_PTR),y ; vram
+ rts
+
+@l2s:
+ ; one character in cell is already used
jsr soft80_checkchar
- bcs @l2a ; char at current position => overwrite 1st
+ bcs @sk1 ; char at current position => overwrite 1st
+
+ lda CURS_X
+ and #$01
+ beq @sk3 ; jump if even xpos
+@sk2:
+ ; colram = textcol
+ lda __textcolor
+ inc $01 ; $35
+ sta (CRAM_PTR),y ; colram
+ stx $01 ; $34
+ rts
+@sk3:
; colram=vram
lda (CRAM_PTR),y ; vram
- inc $01
+ inc $01 ; $35
sta (CRAM_PTR),y ; colram
- stx $01 ;$34
-
- ;jmp @l2a
-
-@l2s:
- ; colram!=bgcolor => alread 2 chars in cell
-@l2a:
-
- ; Set color
+ stx $01 ; $34
+@sk1:
+ ; vram = textcol
lda CHARCOLOR
sta (CRAM_PTR),y ; vram
-
rts
; test if there is a space or a character at current position
sec
rts
-;--- end color vodoo
.endif
projects / cc65 / blobdiff