1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
|
INCLUDE "constants.asm"
SECTION "Video Copy functions", ROM0[$0D2A]
FarCopyData: ; d2a (0:d2a)
; Identical to FarCopyBytes except for tail call optimization
; Copy bc 2bpp bytes from a:hl to de.
ld [wBuffer], a
ldh a, [hROMBank]
push af
ld a, [wBuffer]
call Bankswitch
call CopyBytes
pop af
call Bankswitch
ret
FarCopyDataDouble: ; d3e (0:d3e)
; Copy and expand bc 1bpp bytes from a:hl to de.
ld [wBuffer], a
ldh a, [hROMBank]
push af
ld a, [wBuffer]
call Bankswitch
ld a, h
ld h, d
ld d, a
ld a, l
ld l, e
ld e, a
ld a, b
and a
jr z, .copy_small
ld a, c
and a
jr z, .next
.copy_small
inc b
.next
ld a, [de]
inc de
ld [hli], a
ld [hli], a
dec c
jr nz, .next
dec b
jr nz, .next
pop af
call Bankswitch
ret
CopyVideoData:: ; d68 (0:d68)
; Wait for the next VBlank, then copy c 2bpp
; tiles from b:de to hl, 8 tiles at a time.
; This takes c/8 frames.
ldh a, [hBGMapMode]
push af
xor a ; disable auto-transfer while copying
ldh [hBGMapMode], a
ldh a, [hROMBank]
push af
ld a, b
call Bankswitch
ld a, e
ld [wVBCopySrc], a
ld a, d
ld [wVBCopySrc + 1], a
ld a, l
ld [wVBCopyDst], a
ld a, h
ld [wVBCopyDst + 1], a
.loop
ld a, c
cp $8
jr nc, .keepgoing
ld [wVBCopySize], a
call DelayFrame
pop af
call Bankswitch
pop af
ldh [hBGMapMode], a
ret
.keepgoing
ld a, $8
ld [wVBCopySize], a
call DelayFrame
ld a, c
sub $8
ld c, a
jr .loop
CopyVideoDataDouble:: ; da6 (0:da6)
; Wait for the next VBlank, then copy c 1bpp
; tiles from b:de to hl, 8 tiles at a time.
; This takes c/8 frames.
ldh a, [hBGMapMode]
push af
xor a
ldh [hBGMapMode], a
ldh a, [hROMBank]
push af
ld a, b
call Bankswitch
ld a, e
ld [wVBCopyDoubleSrc], a
ld a, d
ld [wVBCopyDoubleSrc + 1], a
ld a, l
ld [wVBCopyDoubleDst], a
ld a, h
ld [wVBCopyDoubleDst + 1], a
.loop
ld a, c
cp $8
jr nc, .keepgoing
ld [wVBCopyDoubleSize], a
call DelayFrame
pop af
call Bankswitch
pop af
ldh [hBGMapMode], a
ret
.keepgoing
ld a, $8
ld [wVBCopyDoubleSize], a
call DelayFrame
ld a, c
sub $8
ld c, a
jr .loop
CopyVideoDataOptimized:: ; de4 (0:de4)
; Copy c 2bpp tiles from b:de to hl in VRAM
; using VBlank service or direct copy in
; case LCD is off
ldh a, [rLCDC]
bit rLCDC_ENABLE, a
jp nz, CopyVideoData ; copy video data during vblank while screen is on
push hl ; convert to FarCopyData call
ld h, d
ld l, e
pop de
ld a, b
push af
swap c
ld a, $0f
and c
ld b, a
ld a, $f0
and c
ld c, a
pop af
jp FarCopyData
CopyVideoDataDoubleOptimized: ; dff (0:dff)
; Copy c 1bpp tiles from b:de to hl in VRAM
; using VBlank service or direct copy in
; case LCD is off
ldh a, [rLCDC]
bit rLCDC_ENABLE, a
jp nz, CopyVideoDataDouble
push de
ld d, h
ld e, l
ld a, b
push af
ld h, 0
ld l, c
add hl, hl
add hl, hl
add hl, hl
ld b, h
ld c, l
pop af
pop hl
jp FarCopyDataDouble
; 0xe18
|
