3 * Copyright (C) 1998, 1999, 2000, 2001 ReactOS Team
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
21 * PROJECT: ReactOS VGA16 display driver
22 * FILE: drivers/dd/vga/display/objects/offscreen.c
23 * PURPOSE: Manages off-screen video memory.
26 /* INCLUDES ******************************************************************/
28 #include "../vgaddi.h"
29 #include "../vgavideo/vgavideo.h"
32 /* GLOBALS *******************************************************************/
34 static LIST_ENTRY SavedBitsList;
36 /* FUNCTIONS *****************************************************************/
39 VGADDI_BltFromSavedScreenBits(ULONG DestX,
41 PSAVED_SCREEN_BITS Src,
49 /* Select write mode 1. */
50 WRITE_PORT_UCHAR((PUCHAR)GRA_I, 5);
51 WRITE_PORT_UCHAR((PUCHAR)GRA_D, 1);
53 SrcOffset = (PUCHAR)vidmem + Src->Offset;
54 for (i = 0; i < SizeY; i++)
56 DestOffset = (PUCHAR)vidmem + (i + DestY) * 80 + (DestX >> 3);
57 for (j = 0; j < SizeX; j++, SrcOffset++, DestOffset++)
59 (VOID)READ_REGISTER_UCHAR(SrcOffset);
60 WRITE_REGISTER_UCHAR(DestOffset, 0);
64 /* Select write mode 2. */
65 WRITE_PORT_UCHAR((PUCHAR)GRA_I, 5);
66 WRITE_PORT_UCHAR((PUCHAR)GRA_D, 2);
70 VGADDI_BltToSavedScreenBits(PSAVED_SCREEN_BITS Dest,
80 /* Select write mode 1. */
81 WRITE_PORT_UCHAR((PUCHAR)GRA_I, 5);
82 WRITE_PORT_UCHAR((PUCHAR)GRA_D, 1);
84 DestOffset = (PUCHAR)vidmem + Dest->Offset;
86 for (i = 0; i < SizeY; i++)
88 SrcOffset = (PUCHAR)vidmem + (SourceY + i) * 80 + (SourceX >> 3);
89 for (j = 0; j < SizeX; j++, SrcOffset++, DestOffset++)
91 (VOID)READ_REGISTER_UCHAR(SrcOffset);
92 WRITE_REGISTER_UCHAR(DestOffset, 0);
96 /* Select write mode 2. */
97 WRITE_PORT_UCHAR((PUCHAR)GRA_I, 5);
98 WRITE_PORT_UCHAR((PUCHAR)GRA_D, 2);
102 VGADDI_FreeSavedScreenBits(PSAVED_SCREEN_BITS SavedBits)
104 SavedBits->Free = TRUE;
106 if (SavedBits->ListEntry.Blink != &SavedBitsList)
108 PSAVED_SCREEN_BITS Previous;
110 Previous = CONTAINING_RECORD(SavedBits->ListEntry.Blink,
111 SAVED_SCREEN_BITS, ListEntry);
114 Previous->Size += SavedBits->Size;
115 RemoveEntryList(&SavedBits->ListEntry);
116 EngFreeMem(SavedBits);
117 SavedBits = Previous;
120 if (SavedBits->ListEntry.Flink != &SavedBitsList)
122 PSAVED_SCREEN_BITS Next;
124 Next = CONTAINING_RECORD(SavedBits->ListEntry.Flink, SAVED_SCREEN_BITS,
128 SavedBits->Size += Next->Size;
129 RemoveEntryList(&SavedBits->ListEntry);
130 EngFreeMem(SavedBits);
136 VGADDI_AllocSavedScreenBits(ULONG Size)
138 PSAVED_SCREEN_BITS Current;
139 PLIST_ENTRY CurrentEntry;
140 PSAVED_SCREEN_BITS Best;
141 PSAVED_SCREEN_BITS New;
144 CurrentEntry = SavedBitsList.Flink;
145 while (CurrentEntry != &SavedBitsList)
147 Current = CONTAINING_RECORD(CurrentEntry, SAVED_SCREEN_BITS, ListEntry);
149 if (Current->Free && Current->Size >= Size &&
150 (Best == NULL || (Current->Size - Size) < (Best->Size - Size)))
155 CurrentEntry = CurrentEntry->Flink;
162 if (Best->Size == Size)
169 New = EngAllocMem(0, sizeof(SAVED_SCREEN_BITS), ALLOC_TAG);
171 New->Offset = Best->Offset + Size;
174 InsertHeadList(&Best->ListEntry, &New->ListEntry);
180 VGADDI_InitializeOffScreenMem(ULONG Start, ULONG Length)
182 PSAVED_SCREEN_BITS FreeBits;
184 InitializeListHead(&SavedBitsList);
186 FreeBits = EngAllocMem(0, sizeof(SAVED_SCREEN_BITS), ALLOC_TAG);
187 FreeBits->Free = TRUE;
188 FreeBits->Offset = Start;
189 FreeBits->Size = Length;
190 InsertHeadList(&SavedBitsList, &FreeBits->ListEntry);