openMSX
VDPAccessSlots.cc
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1 #include "VDPAccessSlots.hh"
2 
3 namespace openmsx::VDPAccessSlots {
4 
5 // These tables must contain at least one value that is bigger or equal
6 // to 1368+136. So we extend the data with some cyclic duplicates.
7 
8 // Screen rendering disabled (or vertical border).
9 // This is correct (measured on real V9938) for bitmap and character mode.
10 // TODO also correct for text mode? See 'vdp-timing-2.html for more details.
11 static constexpr int16_t slotsScreenOff[154 + 17] = {
12  0, 8, 16, 24, 32, 40, 48, 56, 64, 72,
13  80, 88, 96, 104, 112, 120, 164, 172, 180, 188,
14  196, 204, 212, 220, 228, 236, 244, 252, 260, 268,
15  276, 292, 300, 308, 316, 324, 332, 340, 348, 356,
16  364, 372, 380, 388, 396, 404, 420, 428, 436, 444,
17  452, 460, 468, 476, 484, 492, 500, 508, 516, 524,
18  532, 548, 556, 564, 572, 580, 588, 596, 604, 612,
19  620, 628, 636, 644, 652, 660, 676, 684, 692, 700,
20  708, 716, 724, 732, 740, 748, 756, 764, 772, 780,
21  788, 804, 812, 820, 828, 836, 844, 852, 860, 868,
22  876, 884, 892, 900, 908, 916, 932, 940, 948, 956,
23  964, 972, 980, 988, 996, 1004, 1012, 1020, 1028, 1036,
24  1044, 1060, 1068, 1076, 1084, 1092, 1100, 1108, 1116, 1124,
25  1132, 1140, 1148, 1156, 1164, 1172, 1188, 1196, 1204, 1212,
26  1220, 1228, 1268, 1276, 1284, 1292, 1300, 1308, 1316, 1324,
27  1334, 1344, 1352, 1360,
28  1368+ 0, 1368+ 8, 1368+16, 1368+ 24, 1368+ 32,
29  1368+ 40, 1368+ 48, 1368+56, 1368+ 64, 1368+ 72,
30  1368+ 80, 1368+ 88, 1368+96, 1368+104, 1368+112,
31  1368+120, 1368+164
32 };
33 
34 // Bitmap mode, sprites disabled.
35 static constexpr int16_t slotsSpritesOff[88 + 16] = {
36  6, 14, 22, 30, 38, 46, 54, 62, 70, 78,
37  86, 94, 102, 110, 118, 162, 170, 182, 188, 214,
38  220, 246, 252, 278, 310, 316, 342, 348, 374, 380,
39  406, 438, 444, 470, 476, 502, 508, 534, 566, 572,
40  598, 604, 630, 636, 662, 694, 700, 726, 732, 758,
41  764, 790, 822, 828, 854, 860, 886, 892, 918, 950,
42  956, 982, 988, 1014, 1020, 1046, 1078, 1084, 1110, 1116,
43  1142, 1148, 1174, 1206, 1212, 1266, 1274, 1282, 1290, 1298,
44  1306, 1314, 1322, 1332, 1342, 1350, 1358, 1366,
45  1368+ 6, 1368+14, 1368+ 22, 1368+ 30, 1368+ 38,
46  1368+ 46, 1368+54, 1368+ 62, 1368+ 70, 1368+ 78,
47  1368+ 86, 1368+94, 1368+102, 1368+110, 1368+118,
48  1368+162,
49 };
50 
51 // Character mode, sprites disabled.
52 // TODO these are not actually measured! See 'vdp-timing-2.html'.
53 // [166,1212] is likely correct
54 // [1270,122] is an educated guess, the amount of slots is likely correct,
55 // but they might be shifted a few cycles forwards or backwards.
56 static constexpr int16_t slotsCharSpritesOff[88 + 17] = {
57  2, 10, 18, 26, 34, 42, 50, 58, 66, 74,
58  82, 90, 98, 106, 114, 122, 166, 174, 188, 194,
59  220, 226, 252, 258, 290, 316, 322, 348, 354, 380,
60  386, 418, 444, 450, 476, 482, 508, 514, 546, 572,
61  578, 604, 610, 636, 642, 674, 700, 706, 732, 738,
62  764, 770, 802, 828, 834, 860, 866, 892, 898, 930,
63  956, 962, 988, 994, 1020, 1026, 1058, 1084, 1090, 1116,
64  1122, 1148, 1154, 1186, 1212, 1218, 1270, 1278, 1286, 1294,
65  1302, 1310, 1318, 1326, 1336, 1346, 1354, 1362,
66  1368+ 2, 1368+ 10, 1368+18, 1368+ 26, 1368+ 34,
67  1368+ 42, 1368+ 50, 1368+58, 1368+ 66, 1368+ 74,
68  1368+ 82, 1368+ 90, 1368+98, 1368+106, 1368+114,
69  1368+122, 1368+166,
70 };
71 
72 // Bitmap mode, sprites enabled.
73 static constexpr int16_t slotsSpritesOn[31 + 3] = {
74  28, 92, 162, 170, 188, 220, 252, 316, 348, 380,
75  444, 476, 508, 572, 604, 636, 700, 732, 764, 828,
76  860, 892, 956, 988, 1020, 1084, 1116, 1148, 1212, 1264,
77  1330,
78  1368+28, 1368+92, 1368+162,
79 };
80 
81 // Character mode, sprites enabled.
82 static constexpr int16_t slotsCharSpritesOn[31 + 3] = {
83  32, 96, 166, 174, 188, 220, 252, 316, 348, 380,
84  444, 476, 508, 572, 604, 636, 700, 732, 764, 828,
85  860, 892, 956, 988, 1020, 1084, 1116, 1148, 1212, 1268,
86  1334,
87  1368+32, 1368+96, 1368+166,
88 };
89 
90 // Text mode.
91 static constexpr int16_t slotsText[47 + 10] = {
92  2, 10, 18, 26, 34, 42, 50, 58, 66, 166,
93  174, 182, 190, 198, 206, 214, 222, 312, 408, 504,
94  600, 696, 792, 888, 984, 1080, 1176, 1206, 1214, 1222,
95  1230, 1238, 1246, 1254, 1262, 1270, 1278, 1286, 1294, 1302,
96  1310, 1318, 1326, 1336, 1346, 1354, 1362,
97  1368+ 2, 1368+10, 1368+18, 1368+26, 1368+ 34,
98  1368+42, 1368+50, 1368+58, 1368+66, 1368+166,
99 };
100 
101 
102 // TMS9918 (MSX1) cycle numbers translated to V99x8 cycles (multiplied by 4).
103 // MSX1 screen off.
104 static constexpr int16_t slotsMsx1ScreenOff[107 + 18] = {
105  4, 12, 20, 28, 36, 44, 52, 60, 68, 76,
106  84, 92, 100, 108, 116, 124, 132, 140, 148, 156,
107  164, 172, 180, 188, 196, 204, 220, 236, 252, 268,
108  284, 300, 316, 332, 348, 364, 380, 396, 412, 428,
109  444, 460, 476, 492, 508, 524, 540, 556, 572, 588,
110  604, 620, 636, 652, 668, 684, 700, 716, 732, 748,
111  764, 780, 796, 812, 828, 844, 860, 876, 892, 908,
112  924, 940, 956, 972, 988, 1004, 1020, 1036, 1052, 1068,
113  1084, 1100, 1116, 1132, 1148, 1164, 1180, 1196, 1212, 1228,
114  1236, 1244, 1252, 1260, 1268, 1276, 1284, 1292, 1300, 1308,
115  1316, 1324, 1332, 1340, 1348, 1356, 1364,
116  1368+ 4, 1368+ 12, 1368+ 20, 1368+ 28, 1368+ 36,
117  1368+ 44, 1368+ 52, 1368+ 60, 1368+ 68, 1368+ 76,
118  1368+ 84, 1368+ 92, 1368+100, 1368+108, 1368+116,
119  1368+124, 1368+132, 1368+140,
120 };
121 
122 // MSX1 graphic mode 1 and 2 (aka screen 1 and 2).
123 static constexpr int16_t slotsMsx1Gfx12[19 + 8] = {
124  4, 12, 20, 28, 116, 124, 132, 140, 220, 348,
125  476, 604, 732, 860, 988, 1116, 1236, 1244, 1364,
126  1368+ 4, 1368+ 12, 1368+ 20, 1368+ 28, 1368+116,
127  1368+124, 1368+132, 1368+140,
128 };
129 
130 // MSX1 graphic mode 3 (aka screen 3).
131 static constexpr int16_t slotsMsx1Gfx3[51 + 8] = {
132  4, 12, 20, 28, 116, 124, 132, 140, 220, 228,
133  260, 292, 324, 348, 356, 388, 420, 452, 476, 484,
134  516, 548, 580, 604, 612, 644, 676, 708, 732, 740,
135  772, 804, 836, 860, 868, 900, 932, 964, 988, 996,
136  1028, 1060, 1092, 1116, 1124, 1156, 1188, 1220, 1236, 1244,
137  1364,
138  1368+ 4, 1368+ 12, 1368+ 20, 1368+ 28, 1368+116,
139  1368+124, 1368+132, 1368+140,
140 };
141 
142 
143 // MSX1 text mode 1 (aka screen 0 width 40).
144 static constexpr int16_t slotsMsx1Text[91 + 18] = {
145  4, 12, 20, 28, 36, 44, 52, 60, 68, 76,
146  84, 92, 100, 108, 116, 124, 132, 140, 148, 156,
147  164, 172, 180, 188, 196, 204, 212, 220, 228, 244,
148  268, 292, 316, 340, 364, 388, 412, 436, 460, 484,
149  508, 532, 556, 580, 604, 628, 652, 676, 700, 724,
150  748, 772, 796, 820, 844, 868, 892, 916, 940, 964,
151  988, 1012, 1036, 1060, 1084, 1108, 1132, 1156, 1180, 1196,
152  1204, 1212, 1220, 1228, 1236, 1244, 1252, 1260, 1268, 1276,
153  1284, 1292, 1300, 1308, 1316, 1324, 1332, 1340, 1348, 1356,
154  1364,
155  1368+ 4, 1368+ 12, 1368+ 20, 1368+ 28, 1368+ 36,
156  1368+ 44, 1368+ 52, 1368+ 60, 1368+ 68, 1368+ 76,
157  1368+ 84, 1368+ 92, 1368+100, 1368+108, 1368+116,
158  1368+124, 1368+132, 1368+140,
159 };
160 
161 // Helper functions to transform the above tables into a format that is easier
162 // (=faster) to work with.
163 
165 {
166  operator const uint8_t*() const { return values; }
167 
168 protected:
169  uint8_t values[NUM_DELTAS * TICKS] = {};
170 };
171 
173 {
174  constexpr CycleTable(bool msx1, const int16_t* slots)
175  {
176  // !!! Keep this in sync with the 'Delta' enum !!!
177  constexpr int delta[NUM_DELTAS] = {
178  0, 1, 16, 24, 28, 32, 40, 48, 64, 72, 88, 104, 120, 128, 136
179  };
180 
181  size_t out = 0;
182  for (auto step : delta) {
183  int p = 0;
184  while (slots[p] < step) ++p;
185  for (int i = 0; i < TICKS; ++i) {
186  if ((slots[p] - i) < step) ++p;
187  assert((slots[p] - i) >= step);
188  unsigned t = slots[p] - i;
189  if (msx1) {
190  if (step <= 40) assert(t < 256);
191  } else {
192  assert(t < 256);
193  }
194  values[out++] = t;
195  }
196  }
197  }
198 };
199 
201 {
202 };
203 
204 // In c++14 these tables are calculated at compile-time.
205 static constexpr CycleTable tabSpritesOn (false, slotsSpritesOn);
206 static constexpr CycleTable tabSpritesOff (false, slotsSpritesOff);
207 static constexpr CycleTable tabCharSpritesOn (false, slotsCharSpritesOn);
208 static constexpr CycleTable tabCharSpritesOff(false, slotsCharSpritesOff);
209 static constexpr CycleTable tabText (false, slotsText);
210 static constexpr CycleTable tabScreenOff (false, slotsScreenOff);
211 static constexpr CycleTable tabMsx1Gfx12 (true, slotsMsx1Gfx12);
212 static constexpr CycleTable tabMsx1Gfx3 (true, slotsMsx1Gfx3);
213 static constexpr CycleTable tabMsx1Text (true, slotsMsx1Text);
214 static constexpr CycleTable tabMsx1ScreenOff (true, slotsMsx1ScreenOff);
215 static constexpr ZeroTable tabBroken;
216 
217 
218 static inline const uint8_t* getTab(const VDP& vdp)
219 {
220  if (vdp.getBrokenCmdTiming()) return tabBroken;
221  bool enabled = vdp.isDisplayEnabled();
222  bool sprites = vdp.spritesEnabledRegister();
223  auto mode = vdp.getDisplayMode();
224  bool bitmap = mode.isBitmapMode();
225  bool text = mode.isTextMode();
226  bool gfx3 = mode.getBase() == DisplayMode::GRAPHIC3;
227 
228  if (vdp.isMSX1VDP()) {
229  if (!enabled) return tabMsx1ScreenOff;
230  return text ? tabMsx1Text
231  : (gfx3 ? tabMsx1Gfx3
232  : tabMsx1Gfx12);
233  // TODO undocumented modes
234  } else {
235  if (!enabled) return tabScreenOff;
236  return bitmap ? (sprites ? tabSpritesOn
237  : tabSpritesOff)
238  : (text ? tabText
239  : (sprites ? tabCharSpritesOn
240  : tabCharSpritesOff));
241  }
242 }
243 
245  EmuTime::param frame_, EmuTime::param time, Delta delta,
246  const VDP& vdp)
247 {
248  VDP::VDPClock frame(frame_);
249  unsigned ticks = frame.getTicksTill_fast(time) % TICKS;
250  auto* tab = getTab(vdp);
251  return time + VDP::VDPClock::duration(tab[delta + ticks]);
252 }
253 
255  EmuTime::param frame, EmuTime::param time, EmuTime::param limit,
256  const VDP& vdp)
257 {
258  auto* tab = getTab(vdp);
259  return Calculator(frame, time, limit, tab);
260 }
261 
262 } // namespace openmsx::VDPAccessSlots
bool getEnum() const noexcept
Definition: EnumSetting.hh:96
bool spritesEnabledRegister() const
Still faster variant (just looks at the sprite-enabled-bit).
Definition: VDP.hh:262
Calculator getCalculator(EmuTime::param frame, EmuTime::param time, EmuTime::param limit, const VDP &vdp)
When many calls to getAccessSlot() are needed, it&#39;s more efficient to instead use this function...
bool getBrokenCmdTiming() const
Value of the cmdTiming setting, true means commands have infinite speed.
Definition: VDP.hh:583
DisplayMode getDisplayMode() const
Get the display mode the VDP is in.
Definition: VDP.hh:141
EmuTime getAccessSlot(EmuTime::param frame, EmuTime::param time, Delta delta, const VDP &vdp)
Return the time of the next available access slot that is at least &#39;delta&#39; cycles later than &#39;time&#39;...
Represents a VDP display mode.
Definition: DisplayMode.hh:14
constexpr CycleTable(bool msx1, const int16_t *slots)
bool isTextMode() const
Is the current mode a text mode? Text1 and Text2 are text modes.
Definition: DisplayMode.hh:131
bool isMSX1VDP() const
Is this an MSX1 VDP?
Definition: VDP.hh:93
VDP-VRAM access slot calculator, meant to be used in the inner loops of the VDPCmdEngine commands...
uint8_t values[NUM_DELTAS *TICKS]
std::array< std::array< uint8_t, 3 >, 16 > getMSX1Palette() const
Get the (fixed) palette for this MSX1 VDP.
Definition: VDP.cc:1482
byte getBase() const
Get the base dispay mode as an integer: M5..M1 combined.
Definition: DisplayMode.hh:116
bool isBitmapMode() const
Is the current mode a bitmap mode? Graphic4 and higher are bitmap modes.
Definition: DisplayMode.hh:142
bool isDisplayEnabled() const
Is the display enabled? Both the regular border and forced blanking by clearing the display enable bi...
Definition: VDP.hh:237