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annotate cd_graphics.c @ 2071:598017ef4b0d segacd

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Fix a few sega cd graphics processor bugs
author Michael Pavone <pavone@retrodev.com>
date Sun, 30 Jan 2022 22:29:04 -0800
parents 8e51c0c3f2e3
children c3241eff3c3a
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2069
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1 #include "cd_graphics.h"
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2 #include "backend.h"
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3
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4 void cd_graphics_init(segacd_context *cd)
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5 {
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6 cd->graphics_int_cycle = CYCLE_NEVER;
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7 }
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8
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9 #define BIT_HFLIP 0x8000
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10
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11 static uint8_t get_src_pixel(segacd_context *cd)
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12 {
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13 uint16_t x = cd->graphics_x >> 11;
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14 uint16_t y = cd->graphics_y >> 11;
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15 cd->graphics_x += cd->graphics_dx;
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16 cd->graphics_x &= 0xFFFFFF;
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17 cd->graphics_y += cd->graphics_dy;
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18 cd->graphics_y &= 0xFFFFFF;
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19 uint16_t stamp_shift, pixel_mask;
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20 uint16_t stamp_num_mask;
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21 if (cd->gate_array[GA_STAMP_SIZE] & BIT_STS) {
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22 //32x32 stamps
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23 stamp_shift = 5;
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24 pixel_mask = 0x1F;
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25 stamp_num_mask = 0x3FC;
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26 } else {
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27 //16x16 stamps
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28 stamp_shift = 4;
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29 pixel_mask = 0xF;
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30 stamp_num_mask = 0x3FF;
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31 }
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32 uint16_t stamp_x = x >> stamp_shift;
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33 uint16_t stamp_y = y >> stamp_shift;
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34 uint16_t max, base_mask;
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35 uint32_t row_shift;
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36 if (cd->gate_array[GA_STAMP_SIZE] & BIT_SMS) {
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37 max = 4096 >> stamp_shift;
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38 base_mask = 0xE000 << ((5 - stamp_shift) << 1);
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39 //128 stamps in 32x32 mode, 256 stamps in 16x16 mode
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40 row_shift = 12 - stamp_shift;
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41 } else {
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42 max = 256 >> stamp_shift;
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43 base_mask = 0xFFE0 << ((5 - stamp_shift) << 1);
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44 //8 stamps in 32x32 mode, 16 stamps in 16x16 mode
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45 row_shift = 8 - stamp_shift;
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46 }
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47 if (stamp_x > max || stamp_y > max) {
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48 if (cd->gate_array[GA_STAMP_SIZE] & BIT_RPT) {
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49 stamp_x &= max - 1;
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50 stamp_y &= max - 1;
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51 } else {
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52 return 0;
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53 }
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54 }
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55 uint32_t address = (cd->gate_array[GA_STAMP_MAP_BASE] & base_mask) << 1;
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56 address += (stamp_y << row_shift) + stamp_x;
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57 uint16_t stamp_def = cd->word_ram[address];
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58 uint16_t stamp_num = stamp_def & stamp_num_mask;
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59 if (!stamp_num) {
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60 //manual says stamp 0 can't be used, I assume that means it's treated as transparent
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61 return 0;
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62 }
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63 uint16_t pixel_x = x & pixel_mask;
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64 uint16_t pixel_y = y & pixel_mask;
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65 if (stamp_def & BIT_HFLIP) {
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66 pixel_x = pixel_mask - pixel_x;
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67 }
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68 uint16_t tmp;
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69 switch (stamp_def >> 13 & 3)
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70 {
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71 case 0:
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72 break;
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73 case 1:
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74 tmp = pixel_y;
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75 pixel_y = pixel_x;
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76 pixel_x = pixel_mask - tmp;
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77 break;
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78 case 2:
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79 tmp = pixel_y;
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80 pixel_y = pixel_mask - pixel_x;
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81 pixel_x = pixel_mask - tmp;
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82 break;
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83 case 3:
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84 tmp = pixel_y;
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85 pixel_y = pixel_mask - pixel_x;
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86 pixel_x = tmp;
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87 break;
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88 }
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89 uint16_t cell_x = pixel_x >> 3;
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90 uint32_t pixel_address = stamp_num << 6;
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91 pixel_address += (pixel_y << 1) + (cell_x << (stamp_shift + 1)) + (pixel_x >> 2 & 1);
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92 uint16_t word = cd->word_ram[pixel_address];
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93 switch (pixel_x & 3)
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94 {
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95 default:
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96 case 0:
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97 return word >> 12;
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98 case 1:
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99 return word >> 8 & 0xF;
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100 case 2:
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101 return word >> 4 & 0xF;
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102 case 3:
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103 return word & 0xF;
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104 }
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105
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106 }
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107
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108 enum {
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109 FETCH_X,
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110 FETCH_Y,
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111 FETCH_DX,
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112 FETCH_DY,
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113 PIXEL0,
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114 PIXEL1,
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115 PIXEL2,
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116 PIXEL3,
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117 DRAW
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118 };
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119
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120 void draw_pixels(segacd_context *cd)
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121 {
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122 uint16_t to_draw = 4 - (cd->graphics_dst_x & 3);
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123 uint16_t x_end = cd->gate_array[GA_IMAGE_BUFFER_HDOTS] + (cd->gate_array[GA_IMAGE_BUFFER_OFFSET] & 3);
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124 if (cd->graphics_dst_x + to_draw > x_end) {
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125 to_draw = cd->gate_array[GA_IMAGE_BUFFER_HDOTS] + (cd->gate_array[GA_IMAGE_BUFFER_OFFSET] & 3) - cd->graphics_dst_x;
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126 }
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127 for(uint16_t i = 0; i < to_draw; i++)
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128 {
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129 uint32_t dst_address = cd->gate_array[GA_IMAGE_BUFFER_START] << 1;
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130 dst_address += cd->graphics_dst_y << 1;
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131 dst_address += cd->graphics_dst_x >> 2 & 1;
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132 dst_address += ((cd->graphics_dst_x >> 3) * cd->gate_array[GA_IMAGE_BUFFER_VCELLS]) << 4;
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parents:
diff changeset
133 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
134 uint16_t pixel = cd->graphics_pixels[i] << pixel_shift;
2071
598017ef4b0d Fix a few sega cd graphics processor bugs
Michael Pavone <pavone@retrodev.com>
parents: 2069
diff changeset
135 uint16_t src_mask_check = 0xF << pixel_shift;
2069
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
136 uint16_t src_mask_keep = ~src_mask_check;
2071
598017ef4b0d Fix a few sega cd graphics processor bugs
Michael Pavone <pavone@retrodev.com>
parents: 2069
diff changeset
137 pixel &= src_mask_check;
2069
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
138 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
139 {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
140 case 0:
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
141 //priority mode off
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
142 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
143 cd->word_ram[dst_address] |= pixel;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
144 break;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
145 case 1:
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
146 //underwrite
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
147 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
148 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
149 cd->word_ram[dst_address] |= pixel;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
150 }
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
151 break;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
152 case 3:
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
153 //overwrite
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
154 if (pixel) {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
155 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
156 cd->word_ram[dst_address] |= pixel;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
157 }
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
158 break;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
159 }
2071
598017ef4b0d Fix a few sega cd graphics processor bugs
Michael Pavone <pavone@retrodev.com>
parents: 2069
diff changeset
160 cd->graphics_dst_x++;
2069
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
161 }
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
162 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
163 cd->graphics_dst_y++;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
164 --cd->gate_array[GA_IMAGE_BUFFER_LINES];
2071
598017ef4b0d Fix a few sega cd graphics processor bugs
Michael Pavone <pavone@retrodev.com>
parents: 2069
diff changeset
165 cd->gate_array[GA_TRACE_VECTOR_BASE] += 2;
2069
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
166 cd->graphics_step = FETCH_X;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
167 } else {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
168 cd->graphics_step = PIXEL0;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
169 }
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
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
172 #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
173 #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
174
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
175 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
176 {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
177 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
178 return;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
179 }
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
180 while (cd->graphics_cycle < cycle)
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
181 {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
182 switch (cd->graphics_step)
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
183 {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
184 case FETCH_X:
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
185 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
186 cd->graphics_cycle += 3*4;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
187 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
188 CHECK_CYCLES;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
189 case FETCH_Y:
2071
598017ef4b0d Fix a few sega cd graphics processor bugs
Michael Pavone <pavone@retrodev.com>
parents: 2069
diff changeset
190 cd->graphics_y = cd->word_ram[(cd->gate_array[GA_TRACE_VECTOR_BASE] << 1) + 1] << 8;
2069
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
191 cd->graphics_cycle += 2*4;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
192 CHECK_CYCLES;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
193 case FETCH_DX:
2071
598017ef4b0d Fix a few sega cd graphics processor bugs
Michael Pavone <pavone@retrodev.com>
parents: 2069
diff changeset
194 cd->graphics_dx = cd->word_ram[(cd->gate_array[GA_TRACE_VECTOR_BASE] << 1) + 2];
2069
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
195 if (cd->graphics_dx & 0x8000) {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
196 cd->graphics_dx |= 0xFF0000;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
197 }
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
198 cd->graphics_cycle += 2*4;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
199 CHECK_CYCLES;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
200 case FETCH_DY:
2071
598017ef4b0d Fix a few sega cd graphics processor bugs
Michael Pavone <pavone@retrodev.com>
parents: 2069
diff changeset
201 cd->graphics_dy = cd->word_ram[(cd->gate_array[GA_TRACE_VECTOR_BASE] << 1) + 3];
2069
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
202 if (cd->graphics_dy & 0x8000) {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
203 cd->graphics_dy |= 0xFF0000;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
204 }
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
205 cd->graphics_cycle += 2*4;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
206 CHECK_CYCLES;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
207 case PIXEL0:
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
208 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
209 cd->graphics_cycle += 2*4;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
210 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
211 cd->graphics_step = DRAW;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
212 CHECK_ONLY;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
213 } else {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
214 CHECK_CYCLES;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
215 }
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
216 case PIXEL1:
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
217 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
218 cd->graphics_cycle += 2*4;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
219 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
220 cd->graphics_step = DRAW;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
221 CHECK_ONLY;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
222 } else {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
223 CHECK_CYCLES;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
224 }
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
225 case PIXEL2:
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
226 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
227 cd->graphics_cycle += 2*4;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
228 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
229 cd->graphics_step = DRAW;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
230 CHECK_ONLY;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
231 } else {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
232 CHECK_CYCLES;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
233 }
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
234 case PIXEL3:
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
235 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
236 cd->graphics_cycle += 2*4;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
237 CHECK_CYCLES;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
238 case DRAW:
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
239 draw_pixels(cd);
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
240 cd->graphics_cycle += 1*4;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
241 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
242 break;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
243 }
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
244 CHECK_ONLY;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
245 }
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 }
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
248
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
249 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
250 {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
251 while (cd->graphics_cycle < cycle)
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 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
254 do_graphics(cd, cycle);
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
255 //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
256 //deal with that here for now
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
257 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
258 {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
259 }
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
260 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
261 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
262 break;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
263 }
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
264 } else {
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
265 cd->graphics_cycle = cycle;
8e51c0c3f2e3 Initial attempt at implementing the Sega CD graphics hardware
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
266 }
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267 }
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268 }
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269 void cd_graphics_start(segacd_context *cd)
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270 {
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271 if (!(cd->gate_array[GA_STAMP_SIZE] & BIT_GRON)) {
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272 printf("grahpics start @ %u\n", cd->graphics_cycle);
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273 cd->gate_array[GA_STAMP_SIZE] |= BIT_GRON;
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274 //Manual scan is bad, but formula appears to be
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275 // vsize * (13 + 2 * hoffset + 9 * (hdots + hoffset - 1))
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276 //with an additional 13? cycle setup cost per line
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277 uint32_t lines = cd->gate_array[GA_IMAGE_BUFFER_LINES];
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278 uint32_t hdots = cd->gate_array[GA_IMAGE_BUFFER_HDOTS];
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279 uint32_t hoffset = cd->gate_array[GA_IMAGE_BUFFER_OFFSET] & 3;
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280 cd->graphics_int_cycle = cd->graphics_cycle + 4 * lines * (13 + 2 * hoffset + 9 * (hdots + hoffset - 1));
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281 cd->graphics_dst_y = cd->gate_array[GA_IMAGE_BUFFER_OFFSET] >> 3;
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282 } else {
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283 printf("graphics start ignored @ %u\n", cd->graphics_cycle);
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284 }
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285
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286 }