openMSX
VDPVRAM.hh
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1 #ifndef VDPVRAM_HH
2 #define VDPVRAM_HH
3 
4 #include "VRAMObserver.hh"
5 #include "VDP.hh"
6 #include "VDPCmdEngine.hh"
7 #include "SimpleDebuggable.hh"
8 #include "Ram.hh"
9 #include "Math.hh"
10 #include "openmsx.hh"
11 #include "likely.hh"
12 #include <cassert>
13 
14 namespace openmsx {
15 
16 class DisplayMode;
17 class SpriteChecker;
18 class Renderer;
19 
20 /*
21 Note: The way VRAM is accessed depends a lot on who is doing the accessing.
22 
23 For example, the ranges:
24 - Table access is done using masks.
25 - Command engine work areas are rectangles.
26 - CPU access always spans full memory.
27 
28 Maybe define an interface with multiple subclasses?
29 Or is that too much of a performance hit?
30 If accessed through the interface, a virtual method call is made.
31 But invoking the objects directly should be inlined.
32 
33 Timing:
34 
35 Each window reflects the state of the VRAM at a specified moment in time.
36 
37 Because the CPU has full-range write access, it is incorrect for any window
38 to be ahead in time compared to the CPU. Because multi-cycle operations are
39 implemented as atomic, it is currently possible that a window which starts
40 an operation slightly before CPU time ends up slightly after CPU time.
41 Solutions:
42 - break up operations in 1-cycle suboperations
43  (very hard to reverse engineer accurately)
44 - do not start an operation until its end time is after CPU time
45  (requires minor rewrite of command engine)
46 - make the code that uses the timestamps resilient to after-CPU times
47  (current implementation; investigate if this is correct)
48 
49 Window ranges are not at fixed. But they can only be changed by the CPU, so
50 they are fixed until CPU time, which subsystems will never go beyond anyway.
51 
52 The only two subsystems with write access are CPU and command engine.
53 The command engine can only start executing a new command if instructed so
54 by the CPU. Therefore it is known which area the command engine can write
55 in until CPU time:
56 - empty, if the command engine is not executing a command
57 - the command's reach, if the command engine is executing a command
58 Currently the command's reach is not computed: full VRAM is used.
59 Taking the Y coordinate into account would speed things up a lot, because
60 usually commands execute on invisible pages, so the number of area overlaps
61 between renderer and command engine would be reduced significantly.
62 Also sprite tables are usually not written by commands.
63 
64 Reading through a window is done as follows:
65 A subsystem reads the VRAM because it is updating itself to a certain moment
66 in time T.
67 1. the subsystems syncs the window to T
68 2. VDPVRAM checks overlap of the window with the command write area
69  no overlap -> go to step 6
70 3. VDPVRAM syncs the command engine to T
71 4. the command engine calls VDPVRAM to write each byte it changes in VRAM,
72  call the times this happens C1, C2, C3...
73 5. at the n-th write, VDPVRAM updates any subsystem with the written address
74  in its window to Cn, this can include the original subsystem
75 6. the window has reached T
76  now the subsystem can update itself to T
77 Using this approach instead of syncing on read makes sure there is no
78 re-entrance on the subsystem update methods.
79 
80 Note: command engine reads through write window when doing logic-ops.
81 So "source window" and "destination window" would be better names.
82 
83 Interesting observation:
84 Each window is at the same moment in time as the command engine (C):
85 - if a window doesn't overlap with the command destination window, it is
86  stable from a moment before C until the CPU time T
87 - if a window overlaps with the command destination window, it cannot be
88  before C (incorrect) or after C (uncertainty)
89 Since there is only one time for the entire VRAM, the VRAM itself can be said
90 to be at C. This is a justification for having the sync method in VDPVRAM
91 instead of in Window.
92 
93 Writing through a window is done as follows:
94 - CPU write: sync with all non-CPU windows, including command engine write
95 - command engine write: sync with non-CPU and non-command engine windows
96 Syncing with a window is only necessary if the write falls into that window.
97 
98 If all non-CPU windows are disjunct, then all subsystems function
99 independently (at least until CPU time), no need for syncs.
100 So what is interesting, is which windows overlap.
101 Since windows change position infrequently, it may be beneficial to
102 precalculate overlaps.
103 Not necessarily though, because even if two windows overlap, a single write
104 may not be inside the other window. So precalculated overlaps only speeds up
105 in the case there is no overlap.
106 Maybe it's not necessary to know exactly which windows overlap with cmdwrite,
107 only to know whether there are any. If not, sync can be skipped.
108 
109 Is it possible to read multiple bytes at the same time?
110 In other words, get a pointer to an array instead of reading single bytes.
111 Yes, but only the first 64 bytes are guaranteed to be correct, because that
112 is the granularity of the color table.
113 But since whatever is reading the VRAM knows what it is operating on, it
114 can decide for itself how many bytes to read.
115 
116 */
117 
118 class DummyVRAMOBserver final : public VRAMObserver
119 {
120 public:
121  void updateVRAM(unsigned /*offset*/, EmuTime::param /*time*/) override {}
122  void updateWindow(bool /*enabled*/, EmuTime::param /*time*/) override {}
123 };
124 
136 {
137 public:
138  VRAMWindow(const VRAMWindow&) = delete;
139  VRAMWindow& operator=(const VRAMWindow&) = delete;
140 
146  inline int getMask() const {
147  assert(isEnabled());
148  return effectiveBaseMask;
149  }
150 
163  inline void setMask(int newBaseMask, int newIndexMask,
164  EmuTime::param time) {
165  origBaseMask = newBaseMask;
166  newBaseMask &= sizeMask;
167  if (isEnabled() &&
168  (newBaseMask == effectiveBaseMask) &&
169  (newIndexMask == indexMask)) {
170  return;
171  }
172  observer->updateWindow(true, time);
173  effectiveBaseMask = newBaseMask;
174  indexMask = newIndexMask;
175  baseAddr = effectiveBaseMask & indexMask; // this enables window
176  combiMask = ~effectiveBaseMask | indexMask;
177  }
178 
182  inline void disable(EmuTime::param time) {
183  observer->updateWindow(false, time);
184  baseAddr = -1;
185  }
186 
190  inline bool isContinuous(unsigned index, unsigned size) const {
191  assert(isEnabled());
192  unsigned endIndex = index + size - 1;
193  unsigned areaBits = Math::floodRight(index ^ endIndex);
194  if ((areaBits & effectiveBaseMask) != areaBits) return false;
195  if ((areaBits & ~indexMask) != areaBits) return false;
196  return true;
197  }
198 
207  inline bool isContinuous(unsigned mask) const {
208  assert(isEnabled());
209  assert((mask & ~indexMask) == mask);
210  return (mask & effectiveBaseMask) == mask;
211  }
212 
219  inline const byte* getReadArea(unsigned index, unsigned size) const {
220  assert(isContinuous(index, size)); (void)size;
221  return &data[effectiveBaseMask & (indexMask | index)];
222  }
223 
234  inline std::pair<const byte*, const byte*> getReadAreaPlanar(
235  unsigned index, unsigned size) const {
236  assert((index & 1) == 0);
237  assert((size & 1) == 0);
238  unsigned endIndex = index + size - 1;
239  unsigned areaBits = Math::floodRight(index ^ endIndex);
240  areaBits = ((areaBits << 16) | (areaBits >> 1)) & 0x1FFFF;
241  (void)areaBits;
242  assert((areaBits & effectiveBaseMask) == areaBits);
243  assert((areaBits & ~indexMask) == areaBits);
244  assert(isEnabled());
245  unsigned addr = effectiveBaseMask & (indexMask | (index >> 1));
246  const byte* ptr0 = &data[addr | 0x00000];
247  const byte* ptr1 = &data[addr | 0x10000];
248  return {ptr0, ptr1};
249  }
250 
254  inline byte readNP(unsigned index) const {
255  assert(isEnabled());
256  return data[effectiveBaseMask & index];
257  }
258 
262  inline byte readPlanar(unsigned index) const {
263  assert(isEnabled());
264  index = ((index & 1) << 16) | ((index & 0x1FFFE) >> 1);
265  unsigned addr = effectiveBaseMask & index;
266  return data[addr];
267  }
268 
271  inline bool hasObserver() const {
272  return observer != &dummyObserver;
273  }
274 
280  inline void setObserver(VRAMObserver* newObserver) {
281  observer = newObserver;
282  }
283 
286  inline void resetObserver() {
287  observer = &dummyObserver;
288  }
289 
297  inline bool isInside(unsigned address) const {
298  return (address & combiMask) == unsigned(baseAddr);
299  }
300 
306  inline void notify(unsigned address, EmuTime::param time) {
307  if (isInside(address)) {
308  observer->updateVRAM(address - baseAddr, time);
309  }
310  }
311 
316  void setSizeMask(unsigned newSizeMask, EmuTime::param time) {
317  sizeMask = newSizeMask;
318  if (isEnabled()) {
319  setMask(origBaseMask, indexMask, time);
320  }
321  }
322 
323  template<typename Archive>
324  void serialize(Archive& ar, unsigned version);
325 
326 private:
327  inline bool isEnabled() const {
328  return baseAddr != -1;
329  }
330 
333  friend class VDPVRAM;
334 
338  explicit VRAMWindow(Ram& vram);
339 
342  byte* data;
343 
348  VRAMObserver* observer;
349 
352  int origBaseMask;
353 
357  int effectiveBaseMask;
358 
361  int indexMask;
362 
366  int baseAddr;
367 
370  int combiMask;
371 
376  int sizeMask;
377 
378  static inline DummyVRAMOBserver dummyObserver;
379 };
380 
385 class VDPVRAM
386 {
387 public:
388  VDPVRAM(const VDPVRAM&) = delete;
389  VDPVRAM& operator=(const VDPVRAM&) = delete;
390 
391  VDPVRAM(VDP& vdp, unsigned size, EmuTime::param time);
392 
395  void clear();
396 
401  inline void sync(EmuTime::param time) {
402  assert(vdp.isInsideFrame(time));
403  cmdEngine->sync(time);
404  }
405 
412  inline void cmdWrite(unsigned address, byte value, EmuTime::param time) {
413  #ifdef DEBUG
414  // Rewriting history is not allowed.
415  assert(time >= vramTime);
416  #endif
417  assert(vdp.isInsideFrame(time));
418 
419  // handle mirroring and non-present ram chips
420  address &= sizeMask;
421  if (unlikely(address >= actualSize)) {
422  // 192kb vram is mirroring is handled elsewhere
423  assert(address < 0x30000);
424  // only happens in case of 16kb vram while you write
425  // to range [0x4000,0x8000)
426  return;
427  }
428 
429  writeCommon(address, value, time);
430  }
431 
437  inline void cpuWrite(unsigned address, byte value, EmuTime::param time) {
438  #ifdef DEBUG
439  // Rewriting history is not allowed.
440  assert(time >= vramTime);
441  #endif
442  assert(vdp.isInsideFrame(time));
443 
444  // handle mirroring and non-present ram chips
445  address &= sizeMask;
446  if (unlikely(address >= actualSize)) {
447  // 192kb vram is mirroring is handled elsewhere
448  assert(address < 0x30000);
449  // only happens in case of 16kb vram while you write
450  // to range [0x4000,0x8000)
451  return;
452  }
453 
454  // We should still sync with cmdEngine, even if the VRAM already
455  // contains the value we're about to write (e.g. it's possible
456  // syncing with cmdEngine changes that value, and this write
457  // restores it again). This fixes bug:
458  // [2844043] Hinotori - Firebird small graphics corruption
459  if (cmdReadWindow .isInside(address) ||
460  cmdWriteWindow.isInside(address)) {
461  cmdEngine->sync(time);
462  }
463  writeCommon(address, value, time);
464 
465  cmdEngine->stealAccessSlot(time);
466  }
467 
473  inline byte cpuRead(unsigned address, EmuTime::param time) {
474  #ifdef DEBUG
475  // VRAM should never get ahead of CPU.
476  assert(time >= vramTime);
477  #endif
478  assert(vdp.isInsideFrame(time));
479 
480  address &= sizeMask;
481  if (cmdWriteWindow.isInside(address)) {
482  cmdEngine->sync(time);
483  }
484  cmdEngine->stealAccessSlot(time);
485 
486  #ifdef DEBUG
487  vramTime = time;
488  #endif
489  return data[address];
490  }
491 
500  void updateDisplayMode(DisplayMode mode, bool cmdBit, EmuTime::param time);
501 
508  void updateDisplayEnabled(bool enabled, EmuTime::param time);
509 
514  void updateSpritesEnabled(bool enabled, EmuTime::param time);
515 
520  void updateVRMode(bool mode, EmuTime::param time);
521 
522  void setRenderer(Renderer* renderer, EmuTime::param time);
523 
526  unsigned getSize() const {
527  return actualSize;
528  }
529 
532  inline void setSpriteChecker(SpriteChecker* newSpriteChecker) {
533  spriteChecker = newSpriteChecker;
534  }
535 
538  inline void setCmdEngine(VDPCmdEngine* newCmdEngine) {
539  cmdEngine = newCmdEngine;
540  }
541 
545  void change4k8kMapping(bool mapping8k);
546 
547  template<typename Archive>
548  void serialize(Archive& ar, unsigned version);
549 
550 private:
551  /* Common code of cmdWrite() and cpuWrite()
552  */
553  inline void writeCommon(unsigned address, byte value, EmuTime::param time) {
554  #ifdef DEBUG
555  assert(time >= vramTime);
556  vramTime = time;
557  #endif
558 
559  // Check that VRAM will actually be changed.
560  // A lot of costly syncs can be saved if the same value is written.
561  // For example Penguin Adventure always uploads the whole frame,
562  // even if it is the same as the previous frame.
563  if (data[address] == value) return;
564 
565  // Subsystem synchronisation should happen before the commit,
566  // to be able to draw backlog using old state.
567  bitmapVisibleWindow.notify(address, time);
568  spriteAttribTable.notify(address, time);
569  spritePatternTable.notify(address, time);
570 
571  data[address] = value;
572 
573  // Cache dirty marking should happen after the commit,
574  // otherwise the cache could be re-validated based on old state.
575 
576  // these two seem to be unused
577  // bitmapCacheWindow.notify(address, time);
578  // nameTable.notify(address, time);
579  assert(!bitmapCacheWindow.hasObserver());
580  assert(!nameTable.hasObserver());
581 
582  // in the past GLRasterizer observed these two, now there are none
583  assert(!colorTable.hasObserver());
584  assert(!patternTable.hasObserver());
585 
586  /* TODO:
587  There seems to be a significant difference between subsystem sync
588  and cache admin. One example is the code above, the other is
589  updateWindow, where subsystem sync is interested in windows that
590  were enabled before (new state doesn't matter), while cache admin
591  is interested in windows that become enabled (old state doesn't
592  matter).
593  Does this mean it makes sense to have separate VRAMWindow like
594  classes for each category?
595  Note: In the future, sprites may switch category, or fall in both.
596  */
597  }
598 
599  void setSizeMask(EmuTime::param time);
600 
603  VDP& vdp;
604 
607  Ram data;
608 
614  class LogicalVRAMDebuggable final : public SimpleDebuggable {
615  public:
616  explicit LogicalVRAMDebuggable(VDP& vdp);
617  byte read(unsigned address, EmuTime::param time) override;
618  void write(unsigned address, byte value, EmuTime::param time) override;
619  private:
620  unsigned transform(unsigned address);
621  } logicalVRAMDebug;
622 
627  struct PhysicalVRAMDebuggable final : SimpleDebuggable {
628  PhysicalVRAMDebuggable(VDP& vdp, unsigned actualSize);
629  byte read(unsigned address, EmuTime::param time) override;
630  void write(unsigned address, byte value, EmuTime::param time) override;
631  } physicalVRAMDebug;
632 
633  // TODO: Renderer field can be removed, if updateDisplayMode
634  // and updateDisplayEnabled are moved back to VDP.
635  // Is that a good idea?
636  Renderer* renderer;
637 
638  VDPCmdEngine* cmdEngine;
639  SpriteChecker* spriteChecker;
640 
645  #ifdef DEBUG
646  EmuTime vramTime;
647  #endif
648 
653  unsigned sizeMask;
654 
658  const unsigned actualSize;
659 
662  bool vrMode;
663 
664 public:
674 };
675 
676 } // namespace openmsx
677 
678 #endif
openmsx::VDPVRAM
Manages VRAM contents and synchronises the various users of the VRAM.
Definition: VDPVRAM.hh:386
openmsx::VRAMWindow::setMask
void setMask(int newBaseMask, int newIndexMask, EmuTime::param time)
Sets the mask and enables this window.
Definition: VDPVRAM.hh:163
openmsx.hh
openmsx::VDPVRAM::getSize
unsigned getSize() const
Returns the size of VRAM in bytes.
Definition: VDPVRAM.hh:526
openmsx::VRAMWindow::serialize
void serialize(Archive &ar, unsigned version)
Definition: VDPVRAM.cc:310
openmsx::VDPVRAM::change4k8kMapping
void change4k8kMapping(bool mapping8k)
TMS99x8 VRAM can be mapped in two ways.
Definition: VDPVRAM.cc:239
unlikely
#define unlikely(x)
Definition: likely.hh:15
openmsx::VDP
Unified implementation of MSX Video Display Processors (VDPs).
Definition: VDP.hh:63
openmsx::VRAMWindow::readNP
byte readNP(unsigned index) const
Reads a byte from VRAM in its current state.
Definition: VDPVRAM.hh:254
openmsx::VDPVRAM::setRenderer
void setRenderer(Renderer *renderer, EmuTime::param time)
Definition: VDPVRAM.cc:226
openmsx::VRAMWindow::getReadAreaPlanar
std::pair< const byte *, const byte * > getReadAreaPlanar(unsigned index, unsigned size) const
Similar to getReadArea(), but now with planar addressing mode.
Definition: VDPVRAM.hh:234
openmsx::VRAMWindow::operator=
VRAMWindow & operator=(const VRAMWindow &)=delete
openmsx::VRAMWindow
Specifies an address range in the VRAM.
Definition: VDPVRAM.hh:136
utf8::unchecked::size
size_t size(std::string_view utf8)
Definition: utf8_unchecked.hh:227
VDP.hh
Math::floodRight
constexpr T floodRight(T x) noexcept
Returns the smallest number of the form 2^n-1 that is greater or equal to the given number.
Definition: Math.hh:69
openmsx::SpriteChecker
SpriteChecker
Definition: SpriteChecker.cc:520
openmsx::VDPVRAM::cmdWriteWindow
VRAMWindow cmdWriteWindow
Definition: VDPVRAM.hh:666
openmsx::Renderer
Abstract base class for Renderers.
Definition: Renderer.hh:23
openmsx::VDPVRAM::cmdWrite
void cmdWrite(unsigned address, byte value, EmuTime::param time)
Write a byte from the command engine.
Definition: VDPVRAM.hh:412
openmsx::VDPCmdEngine
VDP command engine by Alex Wulms.
Definition: VDPCmdEngine.hh:23
openmsx::VDPVRAM::cpuRead
byte cpuRead(unsigned address, EmuTime::param time)
Read a byte from VRAM though the CPU interface.
Definition: VDPVRAM.hh:473
openmsx::VDPVRAM::updateVRMode
void updateVRMode(bool mode, EmuTime::param time)
Change between VR=0 and VR=1 mode.
Definition: VDPVRAM.cc:203
openmsx::VRAMObserver::updateVRAM
virtual void updateVRAM(unsigned offset, EmuTime::param time)=0
Informs the observer of a change in VRAM contents.
openmsx::VRAMWindow::isInside
bool isInside(unsigned address) const
Test whether an address is inside this window.
Definition: VDPVRAM.hh:297
openmsx::VDPVRAM::setCmdEngine
void setCmdEngine(VDPCmdEngine *newCmdEngine)
Necessary because of circular dependencies.
Definition: VDPVRAM.hh:538
ranges::transform
auto transform(InputRange &&range, OutputIter out, UnaryOperation op)
Definition: ranges.hh:161
openmsx::DummyVRAMOBserver::updateWindow
void updateWindow(bool, EmuTime::param) override
Informs the observer that the entire VRAM window will change.
Definition: VDPVRAM.hh:122
openmsx::Ram
Ram
Definition: Ram.cc:125
openmsx::VDPVRAM::bitmapCacheWindow
VRAMWindow bitmapCacheWindow
Definition: VDPVRAM.hh:671
openmsx::VRAMWindow::readPlanar
byte readPlanar(unsigned index) const
Similar to readNP, but now with planar addressing.
Definition: VDPVRAM.hh:262
openmsx::VDPVRAM::cpuWrite
void cpuWrite(unsigned address, byte value, EmuTime::param time)
Write a byte to VRAM through the CPU interface.
Definition: VDPVRAM.hh:437
openmsx::DisplayMode
Represents a VDP display mode.
Definition: DisplayMode.hh:16
openmsx::VRAMWindow::notify
void notify(unsigned address, EmuTime::param time)
Notifies the observer of this window of a VRAM change, if the changes address is inside this window.
Definition: VDPVRAM.hh:306
openmsx::VRAMObserver
Interface that can be registered at VRAMWindow, to be called when the contents of the VRAM inside tha...
Definition: VRAMObserver.hh:11
Ram.hh
likely.hh
openmsx::VDPVRAM::bitmapVisibleWindow
VRAMWindow bitmapVisibleWindow
Definition: VDPVRAM.hh:670
openmsx::VDPVRAM::colorTable
VRAMWindow colorTable
Definition: VDPVRAM.hh:668
openmsx::VDPVRAM::updateSpritesEnabled
void updateSpritesEnabled(bool enabled, EmuTime::param time)
Used by the VDP to signal sprites enabled changes.
Definition: VDPVRAM.cc:167
openmsx::VDPCmdEngine
VDPCmdEngine
Definition: VDPCmdEngine.cc:2642
openmsx::SpriteChecker
Definition: SpriteChecker.hh:19
openmsx::SimpleDebuggable::write
void write(unsigned address, byte value) override
Definition: SimpleDebuggable.cc:44
openmsx::VDPVRAM::spritePatternTable
VRAMWindow spritePatternTable
Definition: VDPVRAM.hh:673
openmsx::VRAMWindow::isContinuous
bool isContinuous(unsigned index, unsigned size) const
Is the given index range continuous in VRAM (iow there's no mirroring) Only if the range is continuou...
Definition: VDPVRAM.hh:190
openmsx::VDPVRAM::clear
void clear()
Initialize VRAM content to power-up state.
Definition: VDPVRAM.cc:138
openmsx::VDPCmdEngine::sync
void sync(EmuTime::param time)
Synchronises the command engine with the VDP.
Definition: VDPCmdEngine.hh:37
openmsx::VDPVRAM::sync
void sync(EmuTime::param time)
Update VRAM state to specified moment in time.
Definition: VDPVRAM.hh:401
openmsx::VDPCmdEngine::stealAccessSlot
void stealAccessSlot(EmuTime::param time)
Steal a VRAM access slot from the CmdEngine.
Definition: VDPCmdEngine.hh:46
openmsx::VRAMWindow::setObserver
void setObserver(VRAMObserver *newObserver)
Register an observer on this VRAM window.
Definition: VDPVRAM.hh:280
SimpleDebuggable.hh
openmsx::VDPVRAM::spriteAttribTable
VRAMWindow spriteAttribTable
Definition: VDPVRAM.hh:672
openmsx::VDPVRAM::setSpriteChecker
void setSpriteChecker(SpriteChecker *newSpriteChecker)
Necessary because of circular dependencies.
Definition: VDPVRAM.hh:532
openmsx::DummyVRAMOBserver::updateVRAM
void updateVRAM(unsigned, EmuTime::param) override
Informs the observer of a change in VRAM contents.
Definition: VDPVRAM.hh:121
openmsx::VRAMWindow::disable
void disable(EmuTime::param time)
Disable this window: no address will be considered inside.
Definition: VDPVRAM.hh:182
openmsx::VDPVRAM::serialize
void serialize(Archive &ar, unsigned version)
Definition: VDPVRAM.cc:323
openmsx::VDPVRAM::cmdReadWindow
VRAMWindow cmdReadWindow
Definition: VDPVRAM.hh:665
openmsx::VDP
VDP
Definition: VDP.cc:1918
openmsx::VDPVRAM::nameTable
VRAMWindow nameTable
Definition: VDPVRAM.hh:667
openmsx::Ram
Definition: Ram.hh:16
openmsx::VDPVRAM::updateDisplayMode
void updateDisplayMode(DisplayMode mode, bool cmdBit, EmuTime::param time)
Used by the VDP to signal display mode changes.
Definition: VDPVRAM.cc:151
openmsx::VDPVRAM::VDPVRAM
VDPVRAM(const VDPVRAM &)=delete
openmsx::VRAMWindow::hasObserver
bool hasObserver() const
Is there an observer registered for this window?
Definition: VDPVRAM.hh:271
openmsx::VRAMWindow::VRAMWindow
VRAMWindow(const VRAMWindow &)=delete
openmsx::VDPVRAM::updateDisplayEnabled
void updateDisplayEnabled(bool enabled, EmuTime::param time)
Used by the VDP to signal display enabled changes.
Definition: VDPVRAM.cc:159
openmsx::mask
constexpr nibble mask[4][13]
Definition: RP5C01.cc:33
openmsx::VRAMWindow::resetObserver
void resetObserver()
Unregister the observer of this VRAM window.
Definition: VDPVRAM.hh:286
VDPCmdEngine.hh
openmsx::VDPVRAM::operator=
VDPVRAM & operator=(const VDPVRAM &)=delete
openmsx::DummyVRAMOBserver
Definition: VDPVRAM.hh:119
openmsx::VRAMWindow::getMask
int getMask() const
Gets the mask for this window.
Definition: VDPVRAM.hh:146
openmsx::VDPVRAM::patternTable
VRAMWindow patternTable
Definition: VDPVRAM.hh:669
openmsx::VDP::isInsideFrame
bool isInsideFrame(EmuTime::param time) const
Is the given timestamp inside the current frame? Mainly useful for debugging, because relevant timest...
Definition: VDP.hh:510
Math.hh
openmsx::VRAMWindow::isContinuous
bool isContinuous(unsigned mask) const
Alternative version to check whether a region is continuous in VRAM.
Definition: VDPVRAM.hh:207
openmsx::VRAMWindow::getReadArea
const byte * getReadArea(unsigned index, unsigned size) const
Gets a pointer to a contiguous part of the VRAM.
Definition: VDPVRAM.hh:219
openmsx::VRAMWindow::setSizeMask
void setSizeMask(unsigned newSizeMask, EmuTime::param time)
Inform VRAMWindow of changed sizeMask.
Definition: VDPVRAM.hh:316
openmsx
This file implemented 3 utility functions:
Definition: Autofire.cc:5
VRAMObserver.hh
openmsx::SimpleDebuggable::read
byte read(unsigned address) override
Definition: SimpleDebuggable.cc:34
openmsx::VRAMObserver::updateWindow
virtual void updateWindow(bool enabled, EmuTime::param time)=0
Informs the observer that the entire VRAM window will change.