Selectable amount of rewind states no longer dummy. Fixed loading rewind when none left. Todo: make the state prior loadable too.

zsnes/src/cpu/execute.asm

@@ -55,21 +55,17 @@ EXTSYM fxbit67pcal,SfxSFR,nosprincr,cpucycle,switchtovirqdeb,switchtonmideb
 EXTSYM MovieSeekBehind,SaveSramData,BackupCVFrame,RestoreCVFrame,loadstate
 EXTSYM KeyInsrtChap,KeyNextChap,KeyPrevChap,MovieInsertChapter,MovieSeekAhead
 EXTSYM ResetDuringMovie,EMUPauseKey,INCRFrameKey,MovieWaiting,NoInputRead
-
+EXTSYM AllocatedRewindStates
 
 %ifdef __MSDOS__
 EXTSYM dssel
 %endif
 
 SECTION .data
-NEWSYM CBackupPos, dd 0
-NEWSYM PBackupPos, dd 0
 NEWSYM tempedx, dd 0
 NEWSYM tempesi, dd 0
 NEWSYM tempedi, dd 0
 NEWSYM tempebp, dd 0
-NEWSYM RewindOldPos, dd 0
-NEWSYM RewindPos, dd 0
 NEWSYM RewindTimer, dd 0
 NEWSYM BackState, db 1
 NEWSYM BackStateSize, dd 6
@@ -96,76 +92,39 @@ NEWSYM ProcessRewind
     cmp byte[pressed+eax],1
     jne near .notokay
     mov byte[pressed+eax],2
-    mov eax,[RewindOldPos]
+
-    cmp [RewindPos],eax
-    je near .notokay
-    dec dword[RewindPos]
-    and dword[RewindPos],0Fh
-    mov eax,[RewindOldPos]
-    cmp [RewindPos],eax
-    je .notokay2
-    dec dword[RewindPos]
-    and dword[RewindPos],0Fh
-    mov eax,[RewindPos]
-    mov [PBackupPos],eax
-    push ecx
-    push ebx
     pushad
     call RestoreCVFrame
     popad
+    
     mov esi,[tempesi]
     mov edi,[tempedi]
     mov ebp,[tempebp]
-    ; Clear Cache Check
-    mov ebx,vidmemch2
-    mov ecx,4096+4096+4096
-.next
-    mov byte[ebx],1
-    inc ebx
-    dec ecx
-    jnz .next
-    pop ebx
-    pop ecx
-    inc dword[RewindPos]
-    and dword[RewindPos],0Fh
     mov edx,[tempedx]
 .notokay
     ret
-.notokay2
-    inc dword[RewindPos]
-    and dword[RewindPos],0Fh
-    ret
 
 NEWSYM UpdateRewind
-    push eax
+    cmp byte[AllocatedRewindStates],0
+    je .norewinds
     cmp dword[KeyRewind],0
-    je .notftimer
+    je .norewinds
-    call ProcessRewind
+  
     dec dword[RewindTimer]
-    jnz .notftimer
+    jnz .checkrewind
-    jmp .okay
+    
-.notftimer
-    pop eax
-    ret
-.okay
-    mov eax,[RewindPos]
-    mov [CBackupPos],eax
     mov [tempedx],edx
     mov [tempesi],esi
     mov [tempedi],edi
     mov [tempebp],ebp
+
     pushad
     call BackupCVFrame
     popad
-    inc dword[RewindPos]
+
-    and dword[RewindPos],0Fh
+.checkrewind    
-    mov eax,[RewindOldPos]
+    call ProcessRewind
-    cmp [RewindPos],eax
+.norewinds
-    jne .noteq
-    inc dword[RewindOldPos]
-    and dword[RewindOldPos],0Fh
-.noteq
-    pop eax
     ret
 
 SECTION .data

zsnes/src/zstate.c

@@ -192,47 +192,51 @@ static void memcpyrinc(unsigned char **src, void *dest, size_t len)
 
 extern unsigned int RewindTimer;
 extern unsigned char RewindStates;
+
 unsigned char *StateBackup = 0;
+unsigned char AllocatedRewindStates, LatestRewindPos, EarliestRewindPos;
+
 size_t rewind_state_size, cur_zst_size, old_zst_size;
 
-/* A nice idea, but needs more ported from the assembly first.
+extern unsigned char RewindFrames, romispal;
-size_t RewindPos, RewindEarliestPos;
+extern unsigned char MovieProcessing;
+void zmv_rewind_save(size_t, bool);
+void zmv_rewind_load(size_t, bool);
+
+#define ActualRewindFrames (RewindFrames * (romispal ? 25 : 30))
 
 void BackupCVFrame()
 {
-  unsigned char *RewindBufferPos = StateBackup + RewindPos*rewind_state_size;
+  unsigned char *RewindBufferPos = StateBackup + LatestRewindPos*rewind_state_size;
-  printf("Backing up rewind in slot #%u\n", RewindPos);
+  printf("Backing up rewind in slot #%u\n", LatestRewindPos);
+
+  if (MovieProcessing == 1) { zmv_rewind_save(LatestRewindPos, true); }
+  else if (MovieProcessing == 2) { zmv_rewind_save(LatestRewindPos, false); }
   copy_state_data(RewindBufferPos, memcpyinc, false);
-  RewindPos++;
+
-  if (RewindPos == RewindStates)
+  LatestRewindPos = (LatestRewindPos != AllocatedRewindStates-1) ? LatestRewindPos+1 : 0;
+  if (LatestRewindPos == EarliestRewindPos)
   {
-    RewindPos = 0;
+    EarliestRewindPos = (EarliestRewindPos != AllocatedRewindStates-1) ? EarliestRewindPos+1 : 0;
   }
-  if (RewindPos == RewindEarliestPos)
+      
-  {
+  RewindTimer = ActualRewindFrames;
-    RewindEarliestPos++;
-    if (RewindEarliestPos == RewindStates)
-    {
-      RewindEarliestPos = 0;
-    }
-  }
-  RewindTimer = 60*3;
 }
 
 void RestoreCVFrame()
-{
-  if (RewindPos != RewindEarliestPos)
 {
   unsigned char *RewindBufferPos;
 
-    if (!RewindPos)
+  if (LatestRewindPos != EarliestRewindPos)
   {
-      RewindPos = RewindStates;
+    LatestRewindPos = (LatestRewindPos) ? LatestRewindPos-1 : AllocatedRewindStates-1;
   }
-    RewindPos--;
 
-    RewindBufferPos = StateBackup + RewindPos*rewind_state_size;
+  RewindBufferPos = StateBackup + LatestRewindPos*rewind_state_size;
-    printf("Restoring rewind in slot #%u\n", RewindPos);
+  printf("Restoring rewind in slot #%u\n", LatestRewindPos);
+    
+  if (MovieProcessing == 1) { zmv_rewind_load(LatestRewindPos, true); }
+  else if (MovieProcessing == 2) { zmv_rewind_load(LatestRewindPos, false); }
   copy_state_data(RewindBufferPos, memcpyrinc, true);
 
   //Clear Cache Check
@@ -240,27 +244,7 @@ void RestoreCVFrame()
   memset(vidmemch4, 1, sizeof(vidmemch4));
   memset(vidmemch8, 1, sizeof(vidmemch8));
   
-    RewindTimer = 60*3;
+  RewindTimer = ActualRewindFrames;
-  }
-}
-
-void MultipleFrameBack(unsigned int i)
-{
-  while (i--)
-  {
-    if (RewindPos != RewindEarliestPos)
-    {
-      if (!RewindPos)
-      {
-        RewindPos = RewindStates;
-      }
-      RewindPos--;
-    }
-    else
-    {
-      break;
-    }
-  }
 }
 
 void SetupRewindBuffer()
@@ -272,47 +256,7 @@ void SetupRewindBuffer()
     StateBackup = (unsigned char *)malloc(rewind_state_size*RewindStates);
     if (StateBackup) { break; }
   }
-}
+  AllocatedRewindStates = RewindStates;
-*/
-
-extern unsigned int CBackupPos, PBackupPos, RewindPos, RewindOldPos;
-extern unsigned char RewindFrames, romispal;
-extern unsigned char MovieProcessing;
-void zmv_rewind_save(size_t, bool);
-void zmv_rewind_load(size_t, bool);
-
-#define ActualRewindFrames (RewindFrames * (romispal ? 25 : 30))
-
-void BackupCVFrame()
-{
-  unsigned char *RewindBufferPos = StateBackup + CBackupPos*rewind_state_size;
-  //printf("Backing up rewind in slot #%u\n", CBackupPos);
-  copy_state_data(RewindBufferPos, memcpyinc, false);
-  if (MovieProcessing == 1) { zmv_rewind_save(CBackupPos, true); }
-  else if (MovieProcessing == 2) { zmv_rewind_save(CBackupPos, false); }
-  RewindTimer = ActualRewindFrames;
-}
-
-void RestoreCVFrame()
-{
-  unsigned char *RewindBufferPos = StateBackup + PBackupPos*rewind_state_size;
-  //printf("Restoring rewind in slot #%u\n", PBackupPos);
-  copy_state_data(RewindBufferPos, memcpyrinc, true);
-  if (MovieProcessing == 1) { zmv_rewind_load(PBackupPos, true); }
-  else if (MovieProcessing == 2) { zmv_rewind_load(PBackupPos, false); }
-  RewindTimer = ActualRewindFrames;
-}
-
-void SetupRewindBuffer()
-{
-  if (StateBackup){ free(StateBackup); }
-  RewindStates = 16;
-  StateBackup = 0;
-  StateBackup = (unsigned char *)malloc(rewind_state_size*RewindStates);
-  if (!StateBackup)
-  {
-    asm_call(outofmemory);
-  }
 }
 
 static size_t state_size;
@@ -324,18 +268,15 @@ static void state_size_tally(unsigned char **dest, void *src, size_t len)
 
 void InitRewindVars()
 {
-#ifndef __MSDOS__  //When all the code is ported to C, we can make this work with DOS too
   unsigned char almost_useless_array[1]; //An array is needed for copy_state_data to give the correct size
   state_size = 0;
   copy_state_data(almost_useless_array, state_size_tally, false);
   rewind_state_size = state_size;
 
   SetupRewindBuffer();
-  RewindPos = 0;
+  LatestRewindPos = 0;
-  RewindOldPos = 0;
+  EarliestRewindPos = 0;
-  //RewindEarliestPos = 0;
+  RewindTimer = 1;
-  RewindTimer = ActualRewindFrames;
-#endif
 }
 
 //This is used to preserve system load state between loads