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gbdk-releases/gbdk-lib/libc/gb/drawing.s
Michael Hope 42b070e5e9 Imported gbdk-2.95.
2015-01-10 16:25:08 +01:00

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;; Optimised Drawing library
;; By Jon Fuge (jonny@q-continuum.demon.co.uk) based on original file
;; Updates
;; 990223 Michael Removed mod_col, splitting it up into
;; fg_colour, bg_colour, and draw_mode
;; Note: some optimisations are available with unneded PUSH DE/POP DE's
;; BANKED: checked
.include "global.s"
.globl .init_vram
.globl .copy_vram
.M_SOLID = 0x00
.M_OR = 0x01
.M_XOR = 0x02
.M_AND = 0x03
.if 0
.M_SOLID = 0x10
.M_OR = 0x20
.M_XOR = 0x40
.M_AND = 0x80
.endif
;; Format of mod_col
;; 7 6 5 4 3 2 1 0
;; mode fg bg
.area _HEADER (ABS)
.org .MODE_TABLE+4*.G_MODE
JP .gmode
.module Drawing1
;; Data
.area _BSS
;; Foreground drawing colour
.fg_colour::
.ds 1
;; Background drawing colour
.bg_colour::
.ds 1
;; Drawing mode (.SOILD etc)
.draw_mode:
.ds 1
;; Fill style
.style:
.ds 0x01
;; Various varibles
.x_s:
.ds 2
.y_s:
.ds 2
.delta_x:
.ds 1
.delta_y:
.ds 1
.l_inc:
.ds 1
.l_d:
.ds 2
.dinc1:
.ds 2
.dinc2:
.ds 2
.tx:
.ds 1
.ty:
.ds 1
.area _BASE
;; Enter graphic mode
.gmode::
DI ; Disable interrupts
;; Turn the screen off
LDH A,(.LCDC)
BIT 7,A
JR Z,1$
;; Turn the screen off
CALL .display_off
1$:
LD HL,#0x8000+0x10*0x10
LD DE,#0x1800-0x18*0x10
LD B,#0x00
CALL .init_vram ; Init the charset at 0x8000
;; Install interrupt routines
LD BC,#.vbl
CALL .add_VBL
LD BC,#.lcd
CALL .add_LCD
LD A,#72 ; Set line at which LCD interrupt occurs
LDH (.LYC),A
LD A,#0b01000100 ; Set LCD interrupt to occur when LY = LCY
LDH (.STAT),A
LDH A,(.IE)
OR #0b00000010 ; Enable LCD interrupt
LDH (.IE),A
;; (9*20) = 180 tiles are used in the upper part of the screen
;; (9*20) = 180 tiles are used in the lower part of the screen
;; => We have 24 tiles free
;; We keep 16 at 0x8000->0x80FF, and 8 at 0x9780->97FF
LD HL,#0x9800
LD A,#0x10 ; Keep 16 tiles free
LD BC,#12 ; 12 unused columns
LD E,#18 ; 18 lines
2$:
LD D,#20 ; 20 used columns
3$:
LD (HL+),A
INC A
DEC D
JR NZ,3$
ADD HL,BC
DEC E
JR NZ,2$
;; Turn the screen on
LDH A,(.LCDC)
OR #0b10010001 ; LCD = On
; BG Chr = 0x8000
; BG = On
AND #0b11110111 ; BG Bank = 0x9800
LDH (.LCDC),A
LD A,#.G_MODE
LD (.mode),A
;; Setup the default colours and draw modes
LD A,#.M_SOLID
LD (.draw_mode),A
LD A,#0x03 ; Black
LD (.fg_colour),A
LD A,#0x00 ; White
LD (.bg_colour),A
EI ; Enable interrupts
RET
.vbl::
LDH A,(.LCDC)
OR #0b00010000 ; Set BG Chr to 0x8000
LDH (.LCDC),A
LD A,#72 ; Set line at which LCD interrupt occurs
LDH (.LYC),A
RET
;; Is the STAT check required, as we are already in the HBL?
.lcd::
1$:
LDH A,(.STAT)
BIT 1,A
JR NZ,1$
LDH A,(.LCDC)
AND #0b11101111 ; Set BG Chr to 0x8800
LDH (.LCDC),A
RET
;; Draw a full-screen image at (BC)
.draw_image::
LD HL,#0x8000+0x10*0x10
LD DE,#0x1680
CALL .copy_vram ; Move the charset
RET
;; Replace tile data at (B,C) with data at DE and store old value at HL
.switch_data::
PUSH DE ; Save src
PUSH HL ; Save dst
LD L,B
SLA L
SLA L
SLA L
LD H,#0x00
ADD HL,HL
LD D,H
LD E,L
LD HL,#.y_table
SLA C
SLA C
SLA C
LD B,#0x00
ADD HL,BC
ADD HL,BC
LD B,(HL)
INC HL
LD H,(HL)
LD L,B
ADD HL,DE
LD B,H ; BC = src
LD C,L
POP HL ; HL = dst
PUSH BC ; Save dst
LD A,H
OR L
JR Z,1$
LD DE,#0x10
CALL .copy_vram
1$:
POP HL ; HL = dst
POP BC ; BC = src
LD DE,#0x10
CALL .copy_vram
RET
.area _CODE
;; Advance the cursor
.adv_gcurs::
PUSH HL
LD HL,#.tx ; X coordinate
LD A,#.MAXCURSPOSX
CP (HL)
JR Z,1$
INC (HL)
JR 99$
1$:
LD (HL),#0x00
LD HL,#.ty ; Y coordinate
LD A,#.MAXCURSPOSY
CP (HL)
JR Z,2$
INC (HL)
JR 99$
2$:
LD (HL),#0x00
99$:
POP HL
RET
;; Draw a circle from (B,C) with radius D
.circle::
LD A,B ;Store center values
LD (.x_s),A
LD A,C
LD (.y_s),A
XOR A
LD (.x_s+1),A
LD A,D
LD (.y_s+1),A
CPL
LD L,A
LD H,#0xFF
INC HL
LD BC,#0
ADD HL,BC
LD A,L
LD (.l_d+1),A
LD A,H
LD (.l_d),A
cloop$:
LD A,(.x_s+1)
LD B,A
LD A,(.y_s+1)
SUB B
RET C
LD A,(.style)
OR A
CALL Z,.circplot
LD A,(.l_d)
BIT 7,A
JR Z,ycirc$
LD A,(.style)
OR A
CALL NZ,.horlin
LD A,(.x_s+1)
INC A
LD (.x_s+1),A
LD A,(.l_d)
LD B,A
LD A,(.l_d+1)
LD C,A
LD H,#0
LD A,(.x_s+1)
LD L,A
ADD HL,HL
ADD HL,HL
ADD HL,BC
LD BC,#6
ADD HL,BC
LD A,H
LD (.l_d),A
LD A,L
LD (.l_d+1),A
JR cloop$
ycirc$:
LD A,(.style)
OR A
CALL NZ,.verlin
LD A,(.x_s+1)
INC A
LD (.x_s+1),A
LD B,#0
LD A,(.x_s+1)
LD C,A
LD H,#0xFF
LD A,(.y_s+1)
CPL
LD L,A
INC HL
ADD HL,BC
LD A,(.l_d)
LD B,A
LD A,(.l_d+1)
LD C,A
ADD HL,HL
ADD HL,HL
ADD HL,BC
LD BC,#10
ADD HL,BC
LD A,H
LD (.l_d),A
LD A,L
LD (.l_d+1),A
LD A,(.y_s+1)
DEC A
LD (.y_s+1),A
JP cloop$
.horlin::
LD A,(.x_s)
LD B,A
LD A,(.y_s)
LD C,A
LD A,(.x_s+1)
LD D,A
LD A,(.y_s+1)
LD E,A
PUSH BC
PUSH DE
LD A,B
SUB E
LD H,A
LD A,B
ADD E
LD B,A
LD A,C
ADD D
LD C,A
LD D,H
LD E,C
CALL .line
POP DE
POP BC
LD A,D
OR A
RET Z
PUSH BC
PUSH DE
LD A,B
SUB E
LD H,A
LD A,B
ADD E
LD B,A
LD A,C
SUB D
LD C,A
LD D,H
LD E,C
CALL .line
POP DE
POP BC
RET
.verlin::
LD A,(.x_s)
LD B,A
LD A,(.y_s)
LD C,A
LD A,(.x_s+1)
LD D,A
LD A,(.y_s+1)
LD E,A
PUSH BC
PUSH DE
LD A,B
SUB E
LD H,A
LD A,B
ADD E
LD B,A
LD A,C
ADD D
LD C,A
LD D,H
LD E,C
CALL .line
POP DE
POP BC
PUSH BC
PUSH DE
LD A,B
SUB E
LD H,A
LD A,B
ADD E
LD B,A
LD A,C
SUB D
LD C,A
LD D,H
LD E,C
CALL .line
POP DE
POP BC
LD A,D
SUB E
RET Z
PUSH BC
PUSH DE
LD A,B
SUB D
LD H,A
LD A,B
ADD D
LD B,A
LD A,C
SUB E
LD C,A
LD D,H
LD E,C
CALL .line
POP DE
POP BC
PUSH BC
PUSH DE
LD A,B
SUB D
LD H,A
LD A,B
ADD D
LD B,A
LD A,C
ADD E
LD C,A
LD D,H
LD E,C
CALL .line
POP DE
POP BC
RET
.circplot::
LD A,(.x_s)
LD B,A
LD A,(.y_s)
LD C,A
LD A,(.x_s+1)
LD D,A
LD A,(.y_s+1)
LD E,A
PUSH BC
PUSH DE
LD A,B
ADD D
LD B,A
LD A,C
SUB E
LD C,A
CALL .plot
POP DE
POP BC
PUSH BC
PUSH DE
LD A,B
SUB E
LD B,A
LD A,C
SUB D
LD C,A
CALL .plot
POP DE
POP BC
PUSH BC
PUSH DE
LD A,B
SUB D
LD B,A
LD A,C
ADD E
LD C,A
CALL .plot
POP DE
POP BC
PUSH BC
PUSH DE
LD A,B
ADD E
LD B,A
LD A,C
ADD D
LD C,A
CALL .plot
POP DE
POP BC
LD A,D
OR A
RET Z
SUB E
RET Z
PUSH BC
PUSH DE
LD A,B
SUB D
LD B,A
LD A,C
SUB E
LD C,A
CALL .plot
POP DE
POP BC
PUSH BC
PUSH DE
LD A,B
SUB E
LD B,A
LD A,C
ADD D
LD C,A
CALL .plot
POP DE
POP BC
PUSH BC
PUSH DE
LD A,B
ADD D
LD B,A
LD A,C
ADD E
LD C,A
CALL .plot
POP DE
POP BC
PUSH BC
PUSH DE
LD A,B
ADD E
LD B,A
LD A,C
SUB D
LD C,A
CALL .plot
POP DE
POP BC
RET
;; Draw a box between (B,C) and (D,E)
.box::
LD A,(.x_s)
LD B,A
LD A,(.x_s+1)
LD C,A
SUB B
JR NC,ychk$
LD A,C
LD (.x_s),A
LD A,B
LD (.x_s+1),A
ychk$:
LD A,(.y_s)
LD B,A
LD A,(.y_s+1)
LD C,A
SUB B
JR NC,dbox$
LD A,C
LD (.y_s),A
LD A,B
LD (.y_s+1),A
dbox$:
LD A,(.x_s)
LD B,A
LD D,A
LD A,(.y_s)
LD C,A
LD A,(.y_s+1)
LD E,A
CALL .line
LD A,(.x_s+1)
LD B,A
LD D,A
LD A,(.y_s)
LD C,A
LD A,(.y_s+1)
LD E,A
CALL .line
LD A,(.x_s)
INC A
LD (.x_s),A
LD A,(.x_s+1)
DEC A
LD (.x_s+1),A
LD A,(.x_s)
LD B,A
LD A,(.x_s+1)
LD D,A
LD A,(.y_s)
LD C,A
LD E,A
CALL .line
LD A,(.x_s)
LD B,A
LD A,(.x_s+1)
LD D,A
LD A,(.y_s+1)
LD C,A
LD E,A
CALL .line
LD A,(.style)
OR A
RET Z
LD A,(.x_s)
LD B,A
LD A,(.x_s+1)
SUB B
RET C
LD A,(.y_s)
INC A
LD (.y_s),A
LD A,(.y_s+1)
DEC A
LD (.y_s+1),A
LD A,(.y_s)
LD B,A
LD A,(.y_s+1)
SUB B
RET C
.if 0
LD A,(.mod_col) ;Swap fore + back colours.
LD D,A
AND #0xF0
LD C,A ;Preserve Style
LD A,D
AND #0x0C
RRCA
RRCA
OR C ;Foreground->background + style
LD C,A
LD A,D
AND #0x03
RLCA
RLCA
OR C
LD (.mod_col),A
.else
LD A,(.fg_colour)
LD C,A
LD A,(.bg_colour)
LD (.fg_colour),A
LD A,C
LD (.bg_colour),A
.endif
filllp$:
LD A,(.x_s)
LD B,A
LD A,(.x_s+1)
LD D,A
LD A,(.y_s)
LD C,A
LD E,A
CALL .line
LD A,(.y_s+1)
LD B,A
LD A,(.y_s)
CP B
JR Z,swap$
INC A
LD (.y_s),A
JR filllp$
swap$:
.if 0
LD A,(.mod_col) ;Swap fore + back colours.
LD D,A
AND #0xF0
LD C,A ;Preserve Style
LD A,D
AND #0x0C
RRCA
RRCA
OR C ;Foreground->background + style
LD C,A
LD A,D
AND #0x03
RLCA
RLCA
OR C
LD (.mod_col),A
.else
LD A,(.fg_colour)
LD C,A
LD A,(.bg_colour)
LD (.fg_colour),A
LD A,C
LD (.bg_colour),A
.endif
RET
;; Draw a line between (B,C) and (D,E)
.line::
LD A,C ;Calculate Delta Y
SUB E
JR NC,s1$
CPL
INC A
s1$: LD (.delta_y),A
LD H,A
LD A,B ;Calculate Delta X
SUB D
JR NC,s2$
CPL
INC A
s2$: LD (.delta_x),A
SUB H
JP C,y1
;; Use Delta X
LD A,B
SUB D
JP NC,x2$
LD A,C
SUB E
JR Z,x3$
LD A,#0x00
JR NC,x3$
LD A,#0xFF
JR x3$
x2$:
LD A,E
SUB C
JR Z,x2a$
LD A,#0x00
JR NC,x2a$
LD A,#0xFF
x2a$:
LD B,D
LD C,E ;BC holds start X,Y
x3$:
LD (.l_inc),A ;Store Y increment
LD HL,#.y_table
LD D,#0x00
LD E,C
ADD HL,DE
ADD HL,DE
LD A,(HL+)
LD H,(HL)
LD L,A
LD A,B
AND #0xf8
LD E,A
ADD HL,DE
ADD HL,DE
LD A,(.delta_y)
OR A
JP Z,.xonly
;; Got to do it the hard way.
; Calculate (2*deltay) -> dinc1
PUSH HL
LD H,#0x00
LD L,A
ADD HL,HL
LD A,H
LD (.dinc1),A
LD A,L
LD (.dinc1+1),A
; Calculate (2*deltay)-deltax -> d
LD D,H
LD E,L
LD A,(.delta_x)
CPL
LD L,A
LD H,#0xFF
INC HL
dx1$:
ADD HL,DE
LD A,H
LD (.l_d),A
LD A,L
LD (.l_d+1),A
; Calculate (deltay-deltax)*2 -> dinc2
LD A,(.delta_x)
CPL
LD L,A
LD H,#0xFF
INC HL
LD A,(.delta_y)
LD D,#0x00
LD E,A
ADD HL,DE
ADD HL,HL
LD A,H
LD (.dinc2),A
LD A,L
LD (.dinc2+1),A
POP HL
.if 0
LD A,(.mod_col)
LD D,A
.endif
LD A,(.delta_x)
LD E,A
LD A,B
AND #7
ADD #0x10 ; Table of bits is located at 0x0010
LD C,A
LD B,#0x00
LD A,(BC) ; Get start bit
LD B,A
LD C,A
xloop$:
RRC C
LD A,(.l_d)
BIT 7,A
JR Z,ychg$
PUSH DE
BIT 7,C
JR Z,nbit$
LD A,B
CPL
LD C,A
CALL .wrbyte
DEC HL
LD C,#0x80
LD B,C
nbit$:
LD A,(.l_d+1)
LD D,A
LD A,(.dinc1+1)
ADD D
LD (.l_d+1),A
LD A,(.l_d)
LD D,A
LD A,(.dinc1)
ADC D
LD (.l_d),A
POP DE
JR nchg$
ychg$:
PUSH DE
PUSH BC
LD A,B
CPL
LD C,A
CALL .wrbyte
LD A,(.l_inc)
OR A
JR Z,ydown$
INC HL
LD A,L
AND #0x0F
JR NZ,bound$
LD DE,#0x0130
ADD HL,DE ;Correct screen address
JR bound$
ydown$:
DEC HL
DEC HL
DEC HL
LD A,L
AND #0x0F
XOR #0x0E
JR NZ,bound$
LD DE,#0xFED0
ADD HL,DE ;Correct screen address
bound$:
LD A,(.l_d+1)
LD D,A
LD A,(.dinc2+1)
ADD D
LD (.l_d+1),A
LD A,(.l_d)
LD D,A
LD A,(.dinc2)
ADC D
LD (.l_d),A
POP BC
LD B,C
POP DE
nchg$:
BIT 7,C
JR Z,nadj$
PUSH DE
LD DE,#0x0010
ADD HL,DE ;Correct screen address
POP DE
LD B,C
nadj$:
LD A,B
OR C
LD B,A
DEC E
JP NZ,xloop$
LD A,B
CPL
LD C,A
JP .wrbyte
.xonly::
;; Draw accelerated horizontal line
.if 0
;; xxx needed?
LD A,(.mod_col)
LD D,A
.endif
LD A,(.delta_x)
LD E,A
INC E
LD A,B ;check X
AND #7 ;just look at bottom 3 bits
JR Z,2$
PUSH HL
ADD #0x10 ;Table of bits is located at 0x0010
LD L,A
LD H,#0x00
LD C,(HL)
POP HL
XOR A ;Clear A
1$: RRCA ;Shift data right 1
OR C
DEC E
JR Z,3$
BIT 0,A
JR Z,1$
JR 3$
2$:
LD A,E
DEC A
AND #0xF8
JR Z,4$
JR 8$
3$:
LD B,A
CPL
LD C,A
PUSH DE
CALL .wrbyte
LD DE,#0x0F
ADD HL,DE ;Correct screen address
POP DE
8$: LD A,E
OR A
RET Z
AND #0xF8
JR Z,4$
XOR A
LD C,A
CPL
LD B,A
PUSH DE
CALL .wrbyte
LD DE,#0x0F
ADD HL,DE ;Correct screen address
POP DE
LD A,E
SUB #8
RET Z
LD E,A
JR 8$
4$: LD A,#0x80
5$: DEC E
JR Z,6$
SRA A
JR 5$
6$: LD B,A
CPL
LD C,A
JP .wrbyte
;; Use Delta Y
y1:
LD A,C
SUB E
JP NC,y2$
LD A,B
SUB D
JR Z,y3$
LD A,#0x00
JR NC,y3$
LD A,#0xFF
JR y3$
y2$:
LD A,C
SUB E
JR Z,y2a$
LD A,#0x00
JR NC,y2a$
LD A,#0xFF
y2a$:
LD B,D
LD C,E ;BC holds start X,Y
y3$:
LD (.l_inc),A ;Store X increment
LD HL,#.y_table
LD D,#0x00
LD E,C
ADD HL,DE
ADD HL,DE
LD A,(HL+)
LD H,(HL)
LD L,A
LD A,B
AND #0xf8
LD E,A
ADD HL,DE
ADD HL,DE
.if 0
;; Trashed by later instructions
LD A,(.mod_col)
LD D,A
.endif
LD A,(.delta_y)
LD E,A
INC E
LD A,(.delta_x)
OR A
JP Z,.yonly
;; Got to do it the hard way.
; Calculate (2*deltax) -> dinc1
PUSH HL
LD H,#0x00
LD L,A
ADD HL,HL
LD A,H
LD (.dinc1),A
LD A,L
LD (.dinc1+1),A
; Calculate (2*deltax)-deltay -> d
LD D,H
LD E,L
LD A,(.delta_y)
CPL
LD L,A
LD H,#0xFF
INC HL
dy1$:
ADD HL,DE
LD A,H
LD (.l_d),A
LD A,L
LD (.l_d+1),A
; Calculate (deltax-deltay)*2 -> dinc2
LD A,(.delta_y)
CPL
LD L,A
LD H,#0xFF
INC HL
LD A,(.delta_x)
LD D,#0x00
LD E,A
ADD HL,DE
ADD HL,HL
LD A,H
LD (.dinc2),A
LD A,L
LD (.dinc2+1),A
POP HL
.if 0
;; xxx Not used?
LD A,(.mod_col)
LD D,A
.endif
LD A,(.delta_y)
LD E,A
LD A,B
AND #7
ADD #0x10 ; Table of bits is located at 0x0010
LD C,A
LD B,#0x00
LD A,(BC) ; Get start bit
LD B,A
LD C,A
yloop$:
PUSH DE
PUSH BC
LD A,B
CPL
LD C,A
CALL .wrbyte
INC HL
LD A,L
AND #0x0F
JR NZ,nybound$
LD DE,#0x0130
ADD HL,DE ;Correct screen address
nybound$:
POP BC
LD A,(.l_d)
BIT 7,A
JR Z,xchg$
LD A,(.l_d+1)
LD D,A
LD A,(.dinc1+1)
ADD D
LD (.l_d+1),A
LD A,(.l_d)
LD D,A
LD A,(.dinc1)
ADC D
LD (.l_d),A
JR nchgy$
xchg$:
LD A,(.l_inc)
OR A
JR NZ,yright$
RLC B
BIT 0,B
JR Z,boundy$
LD DE,#0xFFF0
ADD HL,DE ;Correct screen address
JR boundy$
yright$:
RRC B
BIT 7,B
JR Z,boundy$
LD DE,#0x0010
ADD HL,DE ;Correct screen address
boundy$:
LD A,(.l_d+1)
LD D,A
LD A,(.dinc2+1)
ADD D
LD (.l_d+1),A
LD A,(.l_d)
LD D,A
LD A,(.dinc2)
ADC D
LD (.l_d),A
nchgy$:
POP DE
DEC E
JR NZ,yloop$
LD A,B
CPL
LD C,A
JP .wrbyte
.yonly::
;; Draw accelerated vertical line
LD A,B ;check X
AND #7 ;just look at bottom 3 bits
PUSH HL
ADD #0x10 ;Table of bits is located at 0x0010
LD L,A
LD H,#0x00
LD A,(HL) ;Get mask bit
POP HL
LD B,A
CPL
LD C,A
1$: PUSH DE
CALL .wrbyte
INC HL ;Correct screen address
LD A,L
AND #0x0F
JR NZ,2$
LD DE,#0x0130
ADD HL,DE
2$: POP DE
DEC E
RET Z
JR 1$
;; Draw a point at (B,C) with mode and color D
.plot::
LD HL,#.y_table
LD D,#0x00
LD E,C
ADD HL,DE
ADD HL,DE
LD A,(HL+)
LD H,(HL)
LD L,A
LD A,B
AND #0xf8
LD E,A
ADD HL,DE
ADD HL,DE
LD A,B
AND #7
ADD #0x10 ; Table of bits is located at 0x0010
LD C,A
LD B,#0x00
LD A,(BC)
LD B,A
CPL
LD C,A
.wrbyte::
.if 0
LD A,(.mod_col) ; Restore color and mode
LD D,A
BIT 5,D
JR NZ,10$
BIT 6,D
JR NZ,20$
BIT 7,D
JR NZ,30$
.else
LD A,(.fg_colour)
LD D,A
LD A,(.draw_mode)
CP #.M_OR
JR Z,10$
CP #.M_XOR
JR Z,20$
CP #.M_AND
JR Z,30$
.endif
; Fall through to SOLID by default
1$:
;; Solid
LD E,B
.if 0
BIT 2,D
.else
BIT 0,D
.endif
JR NZ,2$
PUSH BC
LD B,#0x00
2$:
.if 0
BIT 3,D
.else
BIT 1,D
.endif
JR NZ,3$
LD E,#0x00
3$:
LDH A,(.STAT)
BIT 1,A
JR NZ,3$
LD A,(HL)
AND C
OR B
LD (HL+),A
LD A,(HL)
AND C
OR E
LD (HL),A
LD A,B
OR A
RET NZ
POP BC
RET
10$:
;; Or
LD C,B
.if 0
BIT 2,D
.else
BIT 0,D
.endif
JR NZ,11$
LD B,#0x00
11$:
.if 0
BIT 3,D
.else
BIT 1,D
.endif
JR NZ,12$
LD C,#0x00
12$:
LDH A,(.STAT)
BIT 1,A
JR NZ,12$
LD A,(HL)
OR B
LD (HL+),A
LD A,(HL)
OR C
LD (HL),A
RET
20$:
;; Xor
LD C,B
.if 0
BIT 2,D
.else
BIT 0,D
.endif
JR NZ,21$
LD B,#0x00
21$:
.if 0
BIT 3,D
.else
BIT 1,D
.endif
JR NZ,22$
LD C,#0x00
22$:
LDH A,(.STAT)
BIT 1,A
JR NZ,22$
LD A,(HL)
XOR B
LD (HL+),A
LD A,(HL)
XOR C
LD (HL),A
RET
30$:
;; And
LD B,C
.if 0
BIT 2,D
.else
BIT 0,D
.endif
JR Z,31$
LD B,#0xFF
31$:
.if 0
BIT 3,D
.else
BIT 1,D
.endif
JR Z,32$
LD C,#0xFF
32$:
LDH A,(.STAT)
BIT 1,A
JR NZ,32$
LD A,(HL)
AND B
LD (HL+),A
LD A,(HL)
AND C
LD (HL),A
RET
;; Get color of pixel at point (B,C) returns in A
.getpix::
LD HL,#.y_table
LD D,#0x00
LD E,C
ADD HL,DE
ADD HL,DE
LD A,(HL+)
LD H,(HL)
LD L,A
LD A,B
AND #0xf8
LD E,A
ADD HL,DE
ADD HL,DE
LD A,B
AND #7
ADD #0x10 ; Table of bits is located at 0x0010
LD C,A
LD B,#0x00
LD A,(BC)
LD C,A
gp$:
LDH A,(.STAT)
BIT 1,A
JR NZ,gp$
LD A,(HL+)
LD D,A
LD A,(HL+)
LD E,A
LD B,#0
LD A,D
AND C
JR Z,npix$
SET 0,B
npix$: LD A,E
AND C
JR Z,end$
SET 1,B
end$: LD E,B
RET
;; Write character C
.wrtchr::
LD HL,#.y_table
LD D,#0x00
LD A,(.ty)
RLCA
RLCA
RLCA
LD E,A
ADD HL,DE
ADD HL,DE
LD B,(HL)
INC HL
LD H,(HL)
LD L,B
LD A,(.tx)
RLCA
RLCA
RLCA
LD E,A
ADD HL,DE
ADD HL,DE
LD A,C
LD B,H
LD C,L
LD H,D
LD L,A
ADD HL,HL
ADD HL,HL
ADD HL,HL
.if 0
LD DE,#.tp1
.else
.globl _font_ibm_fixed_tiles
LD DE,#_font_ibm_fixed_tiles
.endif
ADD HL,DE
LD D,H
LD E,L
LD H,B
LD L,C
.if 0
LD A,(.mod_col)
LD C,A
.else
LD A,(.fg_colour)
LD C,A
.endif
chrloop$:
LD A,(DE)
INC DE
PUSH DE
.if 1
PUSH HL
LD HL,#.bg_colour
LD L,(HL)
.endif
LD B,A
XOR A
.if 0
BIT 0,C
.else
BIT 0,L
.endif
JR Z,a0$
CPL
a0$: OR B
.if 0
BIT 2,C
.else
BIT 0,C
.endif
JR NZ,a1$
XOR B
a1$: LD D,A
XOR A
.if 0
BIT 1,C
.else
BIT 1,L
.endif
JR Z,b0$
CPL
b0$: OR B
.if 0
BIT 3,C
.else
BIT 1,C
.endif
JR NZ,b1$
XOR B
b1$:
LD E,A
.if 1
POP HL
.endif
chrwait$:
LDH A,(.STAT)
BIT 1,A
JR NZ,chrwait$
LD A,D
LD (HL+),A
LD A,E
LD (HL+),A
POP DE
LD A,L
AND #0x0F
JR NZ,chrloop$
RET
.area _CODE
_gotogxy:: ; Banked
LDA HL,.BANKOV(SP) ; Skip return address
LD A,(HL+) ; A = x
LD (.tx),A
LD A,(HL+) ; A = y
LD (.ty),A
RET
_wrtchr:: ; Banked
PUSH BC
LD A,(.mode)
CP #.G_MODE
CALL NZ,.gmode
LDA HL,.BANKOV+2(SP) ; Skip return address and registers
LD A,(HL)
LD C,A ; C = Char to print
CALL .wrtchr
CALL .adv_gcurs
POP BC
RET
_getpix:: ; Banked
PUSH BC
LDA HL,.BANKOV+2(SP) ; Skip return address and registers
LD A,(HL+) ; B = x
LD B,A
LD A,(HL+) ; C = y
LD C,A
CALL .getpix
POP BC
RET
_color:: ; Banked
LDA HL,.BANKOV(SP) ; Skip return address and registers
LD A,(HL+) ; A = Foreground
LD (.fg_colour),a
LD A,(HL+)
LD (.bg_colour),a
LD A,(HL)
LD (.draw_mode),a
RET
_circle:: ; Banked
PUSH BC
LD A,(.mode)
CP #.G_MODE
CALL NZ,.gmode
LDA HL,.BANKOV+2(SP) ; Skip return address and registers
LD A,(HL+) ; B = x
LD B,A
LD A,(HL+) ; C = y
LD C,A
LD A,(HL+) ; D = Radius
LD D,A
LD A,(HL)
LD (.style),A
CALL .circle
POP BC
RET
_box:: ; Banked
PUSH BC
LD A,(.mode)
CP #.G_MODE
CALL NZ,.gmode
LDA HL,.BANKOV+2(SP) ; Skip return address and registers
LD A,(HL+) ; B = x1
LD (.x_s),A
LD A,(HL+) ; C = y1
LD (.y_s),A
LD A,(HL+) ; D = x2
LD (.x_s+1),A
LD A,(HL+) ; E = y2
LD (.y_s+1),A
LD A,(HL)
LD (.style),A
CALL .box
POP BC
RET
_line:: ; Banked
PUSH BC
LD A,(.mode)
CP #.G_MODE
CALL NZ,.gmode
LDA HL,.BANKOV+2(SP) ; Skip return address and registers
LD A,(HL+) ; B = x1
LD B,A
LD A,(HL+) ; C = y1
LD C,A
LD A,(HL+) ; D = x2
LD D,A
LD A,(HL+) ; E = y2
LD E,A
CALL .line
POP BC
RET
_plot_point:: ; Banked
PUSH BC
LD A,(.mode)
CP #.G_MODE
CALL NZ,.gmode
LDA HL,.BANKOV+2(SP) ; Skip return address and registers
LD A,(HL+) ; B = x
LD B,A
LD A,(HL+) ; C = y
LD C,A
CALL .plot
POP BC
RET
;; Old, compatible version of plot()
_plot:: ; Banked
PUSH BC
LD A,(.mode)
CP #.G_MODE
CALL NZ,.gmode
LDA HL,.BANKOV+2(SP) ; Skip return address and registers
LD A,(HL+) ; B = x
LD B,A
LD A,(HL+) ; C = y
LD C,A
LD A,(HL+) ; colour
LD (.fg_colour),A
LD A,(HL+) ; mode
LD (.draw_mode),A
CALL .plot
POP BC
RET
.area _BASE
_switch_data:: ; Non Banked as pointer
PUSH BC
LD A,(.mode)
CP #.G_MODE
CALL NZ,.gmode
LDA HL,4(SP) ; Skip return address and registers
LD A,(HL+) ; B = x
LD B,A
LD A,(HL+) ; C = y
LD C,A
LD A,(HL+) ; DE = src
LD E,A
LD A,(HL+)
LD D,A
LD A,(HL+) ; HL = dst
LD H,(HL)
LD L,A
CALL .switch_data
POP BC
RET
_draw_image:: ; Non banked as pointer
PUSH BC
LD A,(.mode)
CP #.G_MODE
CALL NZ,.gmode
LDA HL,4(SP) ; Skip return address and registers
LD A,(HL+) ; HL = data
LD C,A
LD B,(HL)
CALL .draw_image
POP BC
RET
.area _BASE
.y_table::
.word 0x8100,0x8102,0x8104,0x8106,0x8108,0x810A,0x810C,0x810E
.word 0x8240,0x8242,0x8244,0x8246,0x8248,0x824A,0x824C,0x824E
.word 0x8380,0x8382,0x8384,0x8386,0x8388,0x838A,0x838C,0x838E
.word 0x84C0,0x84C2,0x84C4,0x84C6,0x84C8,0x84CA,0x84CC,0x84CE
.word 0x8600,0x8602,0x8604,0x8606,0x8608,0x860A,0x860C,0x860E
.word 0x8740,0x8742,0x8744,0x8746,0x8748,0x874A,0x874C,0x874E
.word 0x8880,0x8882,0x8884,0x8886,0x8888,0x888A,0x888C,0x888E
.word 0x89C0,0x89C2,0x89C4,0x89C6,0x89C8,0x89CA,0x89CC,0x89CE
.word 0x8B00,0x8B02,0x8B04,0x8B06,0x8B08,0x8B0A,0x8B0C,0x8B0E
.word 0x8C40,0x8C42,0x8C44,0x8C46,0x8C48,0x8C4A,0x8C4C,0x8C4E
.word 0x8D80,0x8D82,0x8D84,0x8D86,0x8D88,0x8D8A,0x8D8C,0x8D8E
.word 0x8EC0,0x8EC2,0x8EC4,0x8EC6,0x8EC8,0x8ECA,0x8ECC,0x8ECE
.word 0x9000,0x9002,0x9004,0x9006,0x9008,0x900A,0x900C,0x900E
.word 0x9140,0x9142,0x9144,0x9146,0x9148,0x914A,0x914C,0x914E
.word 0x9280,0x9282,0x9284,0x9286,0x9288,0x928A,0x928C,0x928E
.word 0x93C0,0x93C2,0x93C4,0x93C6,0x93C8,0x93CA,0x93CC,0x93CE
.word 0x9500,0x9502,0x9504,0x9506,0x9508,0x950A,0x950C,0x950E
.word 0x9640,0x9642,0x9644,0x9646,0x9648,0x964A,0x964C,0x964E
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