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191 lines (166 loc) · 2.38 KB
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Copy pathplot_line2.asm
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191 lines (166 loc) · 2.38 KB
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plot_line1:
ld a,(_xoffset)
add a,e
ld e,a ; de = y*256+x
ld a,(_displaypage)
[2] add a,a
di
out (0x99),a ; set bits 14-16
ld a,14+128
out (0x99),a
ei
ld d,0x40 ; write access
jp _1stblock ; trace 16 pixels
plot_line2:
inc h
ld a,(_xoffset)
add a,e
ld e,a ; de = y*256+x
ld a,(_displaypage)
[2] add a,a
di
out (0x99),a ; set bits 14-16
ld a,14+128
out (0x99),a
ei
ld d,0x50 ; write access
call _2nd ; trace 48 pixels
ld a,(_displaypage)
[2] add a,a
or 1
di
out (0x99),a ; set bits 14-16
ld a,14+128
out (0x99),a
ei
ld d,0x40 ; write access
call _1st ; trace 64 pixels
ld a,(_displaypage)
[2] add a,a
or 2
di
out (0x99),a ; set bits 14-16
ld a,14+128
out (0x99),a
ei
ld d,0x40 ; write access
call _2nd ; trace 48 pixels
ret
; plot_line:
; ld a,(_xoffset)
; add a,e
; ld e,a ; de = y*256+x
; ld a,(_displaypage)
; [2] add a,a
; di
; out (0x99),a ; set bits 14-16
; ld a,14+128
; out (0x99),a
; ei
; ld d,0x40 ; write access
; call _1st
; ld a,(_displaypage)
; [2] add a,a
; or 1
; di
; out (0x99),a ; set bits 14-16
; ld a,14+128
; out (0x99),a
; ei
; ld d,0x40 ; write access
; call _1st
; ld a,(_displaypage)
; [2] add a,a
; or 2
; di
; out (0x99),a ; set bits 14-16
; ld a,14+128
; out (0x99),a
; ei
; ld d,0x40 ; write access
; call _2nd
; ret
_1stblock:
; hl -> Map in RAM
ld a,(hl)
[3] rlca
and 00000111B
add a,:_tiles0
ld (_kBank4),a
ld a,(hl)
and 00011111B
add a,high _tiles0
ld h,a
ld a,(_xoffset)
[4] add a,a
ld l,a
; hl -> tile column
ld bc,16*256+0x98
di
1: ld a,e ;set bits 0-7
out (0x99),a
ld a,d ;set bits 8-13
out (0x99),a
inc d
outi
jp nz,1b
ei
ret
_1st:
; hl -> Map in RAM
push hl
ld a,(hl)
[3] rlca
and 00000111B
add a,:_tiles0
ld (_kBank4),a
ld a,(hl)
and 00011111B
add a,high _tiles0
ld h,a
ld a,(_xoffset)
[4] add a,a
ld l,a
; hl -> tile column
ld bc,16*256+0x98
di
1: ld a,e ;set bits 0-7
out (0x99),a
ld a,d ;set bits 8-13
out (0x99),a
inc d
outi
jp nz,1b
ei
pop hl
inc h
_2nd:
repeat 3
push hl
ld a,(hl)
[3] rlca
and 00000111B
add a,:_tiles0
ld (_kBank4),a
ld a,(hl)
and 00011111B
add a,high _tiles0
ld h,a
ld a,(_xoffset)
[4] add a,a
ld l,a
; hl -> tile column
ld bc,16*256+0x98
di
1: ld a,e ;set bits 0-7
out (0x99),a
ld a,d ;set bits 8-13
out (0x99),a
inc d
outi
jp nz,1b
ei
pop hl
inc h
endrepeat
ret