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
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
|
#ifndef INT10_H
#define INT10_H
#include <stdint.h>
#define BIOS_DATA_AREA_SEGMENT 0x40
static inline uint32_t bda_get_dword(unsigned int offset) {
uint32_t __far *p = MK_FP(BIOS_DATA_AREA_SEGMENT, offset);
return *p;
}
static inline uint16_t bda_get_word(unsigned int offset) {
uint16_t __far *p = MK_FP(BIOS_DATA_AREA_SEGMENT, offset);
return *p;
}
static inline uint8_t bda_get_byte(unsigned int offset) {
uint8_t __far *p = MK_FP(BIOS_DATA_AREA_SEGMENT, offset);
return *p;
}
#define bda_get_ebda_segment() bda_get_word(0x0e)
#define bda_get_video_mode() bda_get_byte(0x49)
#define bda_get_num_columns() bda_get_word(0x4a)
#define bda_get_video_page_size() bda_get_word(0x4c)
#define bda_get_cur_video_page() bda_get_word(0x62)
#define bda_get_last_row() bda_get_byte(0x84)
#define bda_get_tick_count() bda_get_dword(0x6c)
#define bda_get_tick_count_lo() bda_get_word(0x6c)
enum videotype {
VIDEO_UNKNOWN,
VIDEO_TEXT,
VIDEO_CGA,
VIDEO_EGA,
VIDEO_VGA
};
struct modeinfo {
uint8_t mode;
uint8_t page;
enum videotype type;
uint16_t pixels_width, pixels_height;
uint16_t bytes_per_line;
uint16_t odd_scanline_offset;
uint8_t bits_per_pixel;
uint8_t num_planes;
/** Pointer to video memory. */
uint8_t __far * begin;
};
static void get_current_video_mode_info(struct modeinfo *info)
{
uint16_t segment;
info->mode = bda_get_video_mode() & ~0x80;
info->page = bda_get_cur_video_page();
info->odd_scanline_offset = 0;
switch (info->mode) {
case 0:
case 1:
case 2:
case 3: // CGA text modes with 25 rows and variable columns
case 7: // MDA Mono text mode
info->type = VIDEO_TEXT;
info->pixels_width = bda_get_num_columns() * 8;
info->pixels_height = (bda_get_last_row()+1) * 8;
info->bytes_per_line = bda_get_num_columns() * 2;
info->bits_per_pixel = 2 * 8;
info->num_planes = 1;
segment = 0xB800;
break;
case 4:
case 5: // CGA 320x200 4-color
info->type = VIDEO_CGA;
info->pixels_width = 320;
info->pixels_height = 200;
info->bytes_per_line = 80;
info->odd_scanline_offset = 0x2000;
info->bits_per_pixel = 2;
info->num_planes = 1;
segment = 0xB800;
break;
case 6: // CGA 640x200 2-color
info->type = VIDEO_CGA;
info->pixels_width = 640;
info->pixels_height = 200;
info->bytes_per_line = 80;
info->odd_scanline_offset = 0x2000;
info->bits_per_pixel = 1;
info->num_planes = 1;
segment = 0xB800;
break;
case 0xd: // EGA 320x200 16-color
info->type = VIDEO_EGA;
info->pixels_width = 320;
info->pixels_height = 200;
info->bytes_per_line = 40;
info->bits_per_pixel = 1;
info->num_planes = 4;
segment = 0xA000;
break;
case 0xe: // EGA 640x200 16-color
info->type = VIDEO_EGA;
info->pixels_width = 640;
info->pixels_height = 200;
info->bytes_per_line = 80;
info->bits_per_pixel = 1;
info->num_planes = 4;
segment = 0xA000;
break;
case 0xf: // EGA 640x350 4-color
info->type = VIDEO_EGA;
info->pixels_width = 640;
info->pixels_height = 350;
info->bytes_per_line = 80;
info->bits_per_pixel = 1;
info->num_planes = 2;
segment = 0xA000;
break;
case 0x10: // EGA 640x350 16-color
info->type = VIDEO_EGA;
info->pixels_width = 640;
info->pixels_height = 350;
info->bytes_per_line = 80;
info->bits_per_pixel = 1;
info->num_planes = 4;
segment = 0xA000;
break;
case 0x11: // VGA 640x480 2-color
case 0x12: // VGA 640x480 16-color
info->type = VIDEO_VGA;
info->pixels_width = 640;
info->pixels_height = 480;
info->bytes_per_line = 80;
info->bits_per_pixel = 1;
info->num_planes = 4;
segment = 0xA000;
break;
case 0x13: // VGA 320x200 256-color
info->type = VIDEO_VGA;
info->pixels_width = 320;
info->pixels_height = 200;
info->bytes_per_line = 320;
info->bits_per_pixel = 8;
info->num_planes = 1;
segment = 0xA000;
break;
default:
info->type = VIDEO_UNKNOWN;
// Let's put in some default coordinates at leas
info->pixels_width = 640;
info->pixels_height = 200;
segment = 0;
}
info->begin = MK_FP(segment, info->page * bda_get_video_page_size());
}
static inline uint16_t __far * get_video_char(const struct modeinfo *info, unsigned int x, unsigned int y)
{
return (uint16_t __far *) (info->begin + (y * info->bytes_per_line) + (x * 2));
}
static inline uint8_t __far * get_video_scanline(const struct modeinfo *info, unsigned int y)
{
if (info->odd_scanline_offset) {
return info->begin
+ (y%2 * info->odd_scanline_offset)
+ (y/2 * info->bytes_per_line);
} else {
return info->begin
+ (y * info->bytes_per_line);
}
}
struct videoregs {
uint16_t dummy;
};
static void save_video_registers(struct videoregs *regs)
{
// TODO
}
static void restore_video_registers(struct videoregs *regs)
{
// TODO
}
static inline void vga_select_plane(unsigned plane)
{
// TODO
}
#endif
|
