Mercurial > repos > blastem

annotate cd_graphics.c @ 2069:8e51c0c3f2e3 segacd

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Initial attempt at implementing the Sega CD graphics hardware
author Michael Pavone <pavone@retrodev.com>
date Sun, 30 Jan 2022 19:55:33 -0800
parents
children 598017ef4b0d
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
rev   line source
2069
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
1 #include "cd_graphics.h"
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
2 #include "backend.h"
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
3
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
4 void cd_graphics_init(segacd_context *cd)
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
5 {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
6 cd->graphics_int_cycle = CYCLE_NEVER;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
7 }
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
8
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
9 #define BIT_HFLIP 0x8000
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
10
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
11 static uint8_t get_src_pixel(segacd_context *cd)
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
12 {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
13 uint16_t x = cd->graphics_x >> 11;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
14 uint16_t y = cd->graphics_y >> 11;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
15 cd->graphics_x += cd->graphics_dx;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
16 cd->graphics_x &= 0xFFFFFF;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
17 cd->graphics_y += cd->graphics_dy;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
18 cd->graphics_y &= 0xFFFFFF;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
19 uint16_t stamp_shift, pixel_mask;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
20 uint16_t stamp_num_mask;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
21 if (cd->gate_array[GA_STAMP_SIZE] & BIT_STS) {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
22 //32x32 stamps
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
23 stamp_shift = 5;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
24 pixel_mask = 0x1F;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
25 stamp_num_mask = 0x3FC;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
26 } else {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
27 //16x16 stamps
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
28 stamp_shift = 4;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
29 pixel_mask = 0xF;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
30 stamp_num_mask = 0x3FF;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
31 }
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
32 uint16_t stamp_x = x >> stamp_shift;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
33 uint16_t stamp_y = y >> stamp_shift;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
34 uint16_t max, base_mask;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
35 uint32_t row_shift;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
36 if (cd->gate_array[GA_STAMP_SIZE] & BIT_SMS) {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
37 max = 4096 >> stamp_shift;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
38 base_mask = 0xE000 << ((5 - stamp_shift) << 1);
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
39 //128 stamps in 32x32 mode, 256 stamps in 16x16 mode
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
40 row_shift = 12 - stamp_shift;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
41 } else {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
42 max = 256 >> stamp_shift;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
43 base_mask = 0xFFE0 << ((5 - stamp_shift) << 1);
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
44 //8 stamps in 32x32 mode, 16 stamps in 16x16 mode
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
45 row_shift = 8 - stamp_shift;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
46 }
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
47 if (stamp_x > max || stamp_y > max) {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
48 if (cd->gate_array[GA_STAMP_SIZE] & BIT_RPT) {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
49 stamp_x &= max - 1;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
50 stamp_y &= max - 1;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
51 } else {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
52 return 0;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
53 }
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
54 }
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
55 uint32_t address = (cd->gate_array[GA_STAMP_MAP_BASE] & base_mask) << 1;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
56 address += (stamp_y << row_shift) + stamp_x;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
57 uint16_t stamp_def = cd->word_ram[address];
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
58 uint16_t stamp_num = stamp_def & stamp_num_mask;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
59 uint16_t pixel_x = x & pixel_mask;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
60 uint16_t pixel_y = y & pixel_mask;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
61 if (stamp_def & BIT_HFLIP) {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
62 pixel_x = pixel_mask - pixel_x;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
63 }
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
64 uint16_t tmp;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
65 switch (stamp_def >> 13 & 3)
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
66 {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
67 case 0:
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
68 break;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
69 case 1:
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
70 tmp = pixel_y;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
71 pixel_y = pixel_x;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
72 pixel_x = pixel_mask - tmp;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
73 break;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
74 case 2:
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
75 tmp = pixel_y;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
76 pixel_y = pixel_mask - pixel_x;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
77 pixel_x = pixel_mask - tmp;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
78 break;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
79 case 3:
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
80 tmp = pixel_y;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
81 pixel_y = pixel_mask - pixel_x;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
82 pixel_x = tmp;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
83 break;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
84 }
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
85 uint16_t cell_x = pixel_x >> 4;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
86 uint32_t pixel_address = stamp_num << 6;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
87 pixel_address += (pixel_y << 1) + (cell_x << (stamp_shift + 2)) + (pixel_x >> 2 & 1);
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
88 uint16_t word = cd->word_ram[pixel_address];
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
89 switch (pixel_x & 3)
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
90 {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
91 default:
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
92 case 0:
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
93 return word >> 12;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
94 case 1:
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
95 return word >> 8 & 0xF;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
96 case 2:
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
97 return word >> 4 & 0xF;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
98 case 3:
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
99 return word & 0xF;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
100 }
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
101
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
102 }
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
103
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
104 enum {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
105 FETCH_X,
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
106 FETCH_Y,
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
107 FETCH_DX,
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
108 FETCH_DY,
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
109 PIXEL0,
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
110 PIXEL1,
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
111 PIXEL2,
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
112 PIXEL3,
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
113 DRAW
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
114 };
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
115
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
116 void draw_pixels(segacd_context *cd)
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
117 {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
118 uint16_t to_draw = 4 - (cd->graphics_dst_x & 3);
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
119 uint16_t x_end = cd->gate_array[GA_IMAGE_BUFFER_HDOTS] + (cd->gate_array[GA_IMAGE_BUFFER_OFFSET] & 3);
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
120 if (cd->graphics_dst_x + to_draw > x_end) {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
121 to_draw = cd->gate_array[GA_IMAGE_BUFFER_HDOTS] + (cd->gate_array[GA_IMAGE_BUFFER_OFFSET] & 3) - cd->graphics_dst_x;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
122 }
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
123 for(uint16_t i = 0; i < to_draw; i++)
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
124 {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
125 uint32_t dst_address = cd->gate_array[GA_IMAGE_BUFFER_START] << 1;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
126 dst_address += cd->graphics_dst_y << 4;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
127 dst_address += cd->graphics_dst_x >> 2 & 1;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
128 dst_address += ((cd->graphics_dst_x >> 3) * cd->gate_array[GA_IMAGE_BUFFER_VCELLS]) << 4;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
129 uint16_t pixel_shift = 12 - 4 * (cd->graphics_dst_x & 3);
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
130 uint16_t pixel = cd->graphics_pixels[i] << pixel_shift;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
131 uint16_t src_mask_check = 0xFF << pixel_shift;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
132 uint16_t src_mask_keep = ~src_mask_check;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
133 switch (cd->gate_array[1] >> 3 & 3)
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
134 {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
135 case 0:
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
136 //priority mode off
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
137 cd->word_ram[dst_address] &= src_mask_keep;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
138 cd->word_ram[dst_address] |= pixel;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
139 break;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
140 case 1:
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
141 //underwrite
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
142 if (pixel && ! (cd->word_ram[dst_address] & src_mask_check)) {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
143 cd->word_ram[dst_address] &= src_mask_keep;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
144 cd->word_ram[dst_address] |= pixel;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
145 }
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
146 break;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
147 case 3:
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
148 //overwrite
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
149 if (pixel) {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
150 cd->word_ram[dst_address] &= src_mask_keep;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
151 cd->word_ram[dst_address] |= pixel;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
152 }
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
153 break;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
154 }
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
155 }
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
156 cd->graphics_dst_x += to_draw;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
157 if (cd->graphics_dst_x == x_end) {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
158 cd->graphics_dst_y++;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
159 --cd->gate_array[GA_IMAGE_BUFFER_LINES];
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
160 cd->graphics_step = FETCH_X;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
161 } else {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
162 cd->graphics_step = PIXEL0;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
163 }
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
164 }
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
165
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
166 #define CHECK_CYCLES cd->graphics_step++; if(cd->graphics_cycle >= cycle) break
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
167 #define CHECK_ONLY if(cd->graphics_cycle >= cycle) break
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
168
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
169 static void do_graphics(segacd_context *cd, uint32_t cycle)
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
170 {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
171 if (!cd->gate_array[GA_IMAGE_BUFFER_LINES]) {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
172 return;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
173 }
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
174 while (cd->graphics_cycle < cycle)
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
175 {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
176 switch (cd->graphics_step)
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
177 {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
178 case FETCH_X:
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
179 cd->graphics_x = cd->word_ram[cd->gate_array[GA_TRACE_VECTOR_BASE] << 1] << 8;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
180 cd->graphics_cycle += 3*4;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
181 cd->graphics_dst_x = cd->gate_array[GA_IMAGE_BUFFER_OFFSET] & 3;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
182 CHECK_CYCLES;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
183 case FETCH_Y:
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
184 cd->graphics_y = cd->word_ram[cd->gate_array[GA_TRACE_VECTOR_BASE] << 1 + 1] << 8;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
185 cd->graphics_cycle += 2*4;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
186 CHECK_CYCLES;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
187 case FETCH_DX:
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
188 cd->graphics_dx = cd->word_ram[cd->gate_array[GA_TRACE_VECTOR_BASE] << 1 + 2];
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
189 if (cd->graphics_dx & 0x8000) {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
190 cd->graphics_dx |= 0xFF0000;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
191 }
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
192 cd->graphics_cycle += 2*4;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
193 CHECK_CYCLES;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
194 case FETCH_DY:
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
195 cd->graphics_dy = cd->word_ram[cd->gate_array[GA_TRACE_VECTOR_BASE] << 1 + 3];
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
196 if (cd->graphics_dy & 0x8000) {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
197 cd->graphics_dy |= 0xFF0000;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
198 }
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
199 cd->graphics_cycle += 2*4;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
200 CHECK_CYCLES;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
201 case PIXEL0:
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
202 cd->graphics_pixels[0] = get_src_pixel(cd);
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
203 cd->graphics_cycle += 2*4;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
204 if ((cd->graphics_dst_x & 3) == 3 || (cd->graphics_dst_x + 1 == cd->gate_array[GA_IMAGE_BUFFER_HDOTS] + (cd->gate_array[GA_IMAGE_BUFFER_OFFSET] & 3))) {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
205 cd->graphics_step = DRAW;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
206 CHECK_ONLY;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
207 } else {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
208 CHECK_CYCLES;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
209 }
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
210 case PIXEL1:
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
211 cd->graphics_pixels[1] = get_src_pixel(cd);
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
212 cd->graphics_cycle += 2*4;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
213 if ((cd->graphics_dst_x & 3) == 2 || (cd->graphics_dst_x + 2 == cd->gate_array[GA_IMAGE_BUFFER_HDOTS] + (cd->gate_array[GA_IMAGE_BUFFER_OFFSET] & 3))) {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
214 cd->graphics_step = DRAW;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
215 CHECK_ONLY;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
216 } else {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
217 CHECK_CYCLES;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
218 }
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
219 case PIXEL2:
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
220 cd->graphics_pixels[2] = get_src_pixel(cd);
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
221 cd->graphics_cycle += 2*4;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
222 if ((cd->graphics_dst_x & 3) == 1 || (cd->graphics_dst_x + 3 == cd->gate_array[GA_IMAGE_BUFFER_HDOTS] + (cd->gate_array[GA_IMAGE_BUFFER_OFFSET] & 3))) {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
223 cd->graphics_step = DRAW;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
224 CHECK_ONLY;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
225 } else {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
226 CHECK_CYCLES;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
227 }
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
228 case PIXEL3:
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
229 cd->graphics_pixels[3] = get_src_pixel(cd);
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
230 cd->graphics_cycle += 2*4;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
231 CHECK_CYCLES;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
232 case DRAW:
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
233 draw_pixels(cd);
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
234 cd->graphics_cycle += 1*4;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
235 if (!cd->gate_array[GA_IMAGE_BUFFER_LINES]) {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
236 break;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
237 }
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
238 CHECK_ONLY;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
239 }
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
240 }
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
241 }
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
242
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
243 void cd_graphics_run(segacd_context *cd, uint32_t cycle)
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
244 {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
245 while (cd->graphics_cycle < cycle)
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
246 {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
247 if (cd->gate_array[GA_STAMP_SIZE] & BIT_GRON) {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
248 do_graphics(cd, cycle);
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
249 //end calculation and actual emulated execution time probably don't 100% line up yet
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
250 //deal with that here for now
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
251 for(; cd->graphics_cycle < cycle; cd->graphics_cycle += 4)
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
252 {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
253 }
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
254 if (cd->graphics_cycle >= cd->graphics_int_cycle) {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
255 cd->gate_array[GA_STAMP_SIZE] &= ~BIT_GRON;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
256 break;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
257 }
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
258 } else {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
259 cd->graphics_cycle = cycle;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
260 }
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
261 }
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
262 }
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
263 void cd_graphics_start(segacd_context *cd)
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
264 {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
265 if (!(cd->gate_array[GA_STAMP_SIZE] & BIT_GRON)) {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
266 printf("grahpics start @ %u\n", cd->graphics_cycle);
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
267 cd->gate_array[GA_STAMP_SIZE] |= BIT_GRON;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
268 //Manual scan is bad, but formula appears to be
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
269 // vsize * (13 + 2 * hoffset + 9 * (hdots + hoffset - 1))
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
270 //with an additional 13? cycle setup cost per line
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
271 uint32_t lines = cd->gate_array[GA_IMAGE_BUFFER_LINES];
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
272 uint32_t hdots = cd->gate_array[GA_IMAGE_BUFFER_HDOTS];
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
273 uint32_t hoffset = cd->gate_array[GA_IMAGE_BUFFER_OFFSET] & 3;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
274 cd->graphics_int_cycle = cd->graphics_cycle + 4 * lines * (13 + 2 * hoffset + 9 * (hdots + hoffset - 1));
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
275 cd->graphics_dst_y = cd->gate_array[GA_IMAGE_BUFFER_OFFSET] >> 3;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
276 } else {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
277 printf("graphics start ignored @ %u\n", cd->graphics_cycle);
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
278 }
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
279
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
280 }