Intravision/reactos
1
0
Fork 0
mirror of https://github.com/reactos/reactos.git synced 2025-08-05 16:23:01 +00:00
Code Issues Projects Releases Packages Wiki Activity

[NTVDM]

Browse source 
Fix host-to-VGA address translation.


svn path=/trunk/; revision=67280
This commit is contained in:
Aleksandar Andrejevic 2015-04-18 22:00:44 +00:00
parent f033a19054
commit f6e7bd7e87
1 changed files with 6 additions and 12 deletions
Download patch file Download diff file Expand all files Collapse all files

18
reactos/subsystems/mvdm/ntvdm/hardware/video/vga.c
View file

@ -629,13 +629,13 @@ static inline DWORD VgaTranslateReadAddress(DWORD Address)
{ {
/* The lowest two bits are the plane number */ /* The lowest two bits are the plane number */
Plane = Offset & 0x03; Plane = Offset & 0x03;
Offset >>= 2; Offset &= ~3;
} }
else if (VgaGcRegisters[VGA_GC_MODE_REG] & VGA_GC_MODE_OE) else if (VgaGcRegisters[VGA_GC_MODE_REG] & VGA_GC_MODE_OE)
{ {
/* The LSB is the plane number */ /* The LSB is the plane number */
Plane = Offset & 0x01; Plane = Offset & 0x01;
Offset >>= 1; Offset &= ~1;
} }
else else
{ {
@ -643,9 +643,6 @@ static inline DWORD VgaTranslateReadAddress(DWORD Address)
Plane = VgaGcRegisters[VGA_GC_READ_MAP_SEL_REG] & 0x03; Plane = VgaGcRegisters[VGA_GC_READ_MAP_SEL_REG] & 0x03;
} }
/* Multiply the offset by the address size */
Offset *= VgaGetAddressSize();
return Offset + Plane * VGA_BANK_SIZE; return Offset + Plane * VGA_BANK_SIZE;
} }
@ -656,18 +653,15 @@ static inline DWORD VgaTranslateWriteAddress(DWORD Address)
/* Check for chain-4 and odd-even mode */ /* Check for chain-4 and odd-even mode */
if (VgaSeqRegisters[VGA_SEQ_MEM_REG] & VGA_SEQ_MEM_C4) if (VgaSeqRegisters[VGA_SEQ_MEM_REG] & VGA_SEQ_MEM_C4)
{ {
/* Shift the offset to the right by 2 */ /* Clear the lowest two bits since they're used to select the bank */
Offset >>= 2; Offset &= ~3;
} }
else if (VgaGcRegisters[VGA_GC_MODE_REG] & VGA_GC_MODE_OE) else if (VgaGcRegisters[VGA_GC_MODE_REG] & VGA_GC_MODE_OE)
{ {
/* Shift the offset to the right by 1 */ /* Clear the lowest bit since it's used to select odd/even */
Offset >>= 1; Offset &= ~1;
} }
/* Multiply the offset by the address size */
Offset *= VgaGetAddressSize();
/* Return the offset on plane 0 */ /* Return the offset on plane 0 */
return Offset; return Offset;
} }