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[NTVDM:SVGA]

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Chain-4 addressing isn't really the same as packed-pixel addressing.
Also, fix a bug in the optimized odd/even mode reading code.


svn path=/trunk/; revision=72514
This commit is contained in:
Aleksandar Andrejevic 2016-08-30 21:07:26 +00:00
parent aa033a5fc4
commit 8c89d519a9
1 changed files with 57 additions and 3 deletions
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60
reactos/subsystems/mvdm/ntvdm/hardware/video/svga.c
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@ -1797,8 +1797,9 @@ VOID FASTCALL VgaReadMemory(ULONG Address, PVOID Buffer, ULONG Size)
{
VideoAddress = VgaTranslateAddress(Address);
/* Check for chain-4 and odd-even mode */
if (VgaSeqRegisters[VGA_SEQ_MEM_REG] & VGA_SEQ_MEM_C4)
#if 0
/* Packed pixel mode - not used yet */
if (VgaSeqRegisters[SVGA_SEQ_EXT_MODE_REG] & SVGA_SEQ_EXT_MODE_HIGH_RES)
{
/* Just copy from the video memory */
PVOID VideoMemory = &VgaMemory[VideoAddress * VGA_NUM_BANKS + (Address & 3)];
@ -1829,12 +1830,65 @@ VOID FASTCALL VgaReadMemory(ULONG Address, PVOID Buffer, ULONG Size)
#endif
}
}
#endif
/* Check for chain-4 and odd-even mode */
if (VgaSeqRegisters[VGA_SEQ_MEM_REG] & VGA_SEQ_MEM_C4)
{
i = 0;
/* Write the unaligned part first */
if (Address & 3)
{
switch (Address & 3)
{
case 1:
BufPtr[i++] = VgaMemory[VideoAddress * VGA_NUM_BANKS + 1];
case 2:
BufPtr[i++] = VgaMemory[VideoAddress * VGA_NUM_BANKS + 2];
case 3:
BufPtr[i++] = VgaMemory[VideoAddress * VGA_NUM_BANKS + 3];
}
VideoAddress += 4;
}
/* Copy the aligned dwords */
while ((i + 3) < Size)
{
*(PULONG)&BufPtr[i] = *(PULONG)&VgaMemory[VideoAddress * VGA_NUM_BANKS];
i += 4;
VideoAddress += 4;
}
/* Write the remaining part */
if (i < Size)
{
switch (Size - i - 3)
{
case 3:
BufPtr[i] = VgaMemory[VideoAddress * VGA_NUM_BANKS + ((Address + i) & 3)];
i++;
case 2:
BufPtr[i] = VgaMemory[VideoAddress * VGA_NUM_BANKS + ((Address + i) & 3)];
i++;
case 1:
BufPtr[i] = VgaMemory[VideoAddress * VGA_NUM_BANKS + ((Address + i) & 3)];
i++;
}
}
}
else if (VgaGcRegisters[VGA_GC_MODE_REG] & VGA_GC_MODE_OE)
{
i = 0;
/* Check if the starting address is odd */
if (Address & 1) BufPtr[i++] = VgaMemory[(VideoAddress++) * VGA_NUM_BANKS + 1];
if (Address & 1)
{
BufPtr[i++] = VgaMemory[VideoAddress * VGA_NUM_BANKS + 1];
VideoAddress += 2;
}
while (i < (Size - 1))
{