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Definition at line 7 of file bootvid.c. Referenced by VgaSetMode(), VgaZeroVideoMemory(), VidInitialize(), and VidResetDisplay(). {
PUCHAR Base = (PUCHAR)VgaRegisterBase;
USHORT Cmd;
UCHAR Major, Minor;
USHORT Count;
UCHAR Index;
PUSHORT Buffer;
PUSHORT ShortPort;
PUCHAR Port;
UCHAR Value;
USHORT ShortValue;
/* First make sure that we have a Command Stream */
if (!CmdStream) return TRUE;
/* Loop as long as we have commands */
while (*CmdStream)
{
/* Get the Major and Minor Function */
Cmd = *CmdStream;
Major = Cmd & 0xF0;
Minor = Cmd & 0x0F;
/* Move to the next command */
CmdStream++;
/* Check which major function this was */
if (Major == 0x10)
{
/* Now let's see the minor function */
if (Minor & CMD_STREAM_READ)
{
/* Now check the sub-type */
if (Minor & CMD_STREAM_USHORT)
{
/* The port is what is in the stream right now */
ShortPort = UlongToPtr((ULONG)*CmdStream);
/* Move to the next command */
CmdStream++;
/* Read USHORT from the port */
READ_PORT_USHORT(PtrToUlong(Base) + ShortPort);
}
else
{
/* The port is what is in the stream right now */
Port = UlongToPtr((ULONG)*CmdStream);
/* Move to the next command */
CmdStream++;
/* Read UCHAR from the port */
READ_PORT_UCHAR(PtrToUlong(Base) + Port);
}
}
else if (Minor & CMD_STREAM_WRITE_ARRAY)
{
/* Now check the sub-type */
if (Minor & CMD_STREAM_USHORT)
{
/* The port is what is in the stream right now */
ShortPort = UlongToPtr(Cmd);
/* Move to the next command and get the count */
Count = *(CmdStream++);
/* The buffer is what's next in the command stream */
Buffer = CmdStream++;
/* Write USHORT to the port */
WRITE_PORT_BUFFER_USHORT(PtrToUshort(Base) + ShortPort, Buffer, Count);
/* Move past the buffer in the command stream */
CmdStream += Count;
}
else
{
/* The port is what is in the stream right now */
Port = UlongToPtr(Cmd);
/* Move to the next command and get the count */
Count = *(CmdStream++);
/* Add the base to the port */
Port = PtrToUlong(Port) + Base;
/* Move to next command */
CmdStream++;
/* Loop the cmd array */
for (; Count; Count--, CmdStream++)
{
/* Get the byte we're writing */
Value = (UCHAR)*CmdStream;
/* Write UCHAR to the port */
WRITE_PORT_UCHAR(Port, Value);
}
}
}
else if (Minor & CMD_STREAM_USHORT)
{
/* Get the ushort we're writing and advance in the stream */
ShortValue = *CmdStream;
CmdStream++;
/* Write USHORT to the port (which is in cmd) */
WRITE_PORT_USHORT((PUSHORT)Base + Cmd, ShortValue);
}
else
{
/* The port is what is in the stream right now */
Port = UlongToPtr((ULONG)*CmdStream);
/* Get the uchar we're writing */
Value = (UCHAR)*++CmdStream;
/* Move to the next command */
CmdStream++;
/* Write UCHAR to the port (which is in cmd) */
WRITE_PORT_UCHAR(PtrToUlong(Base) + Port, Value);
}
}
else if (Major == 0x20)
{
/* Check the minor function. Note these are not flags anymore. */
switch (Minor)
{
case 0:
/* The port is what is in the stream right now */
ShortPort = UlongToPtr(*CmdStream);
/* Move to the next command and get the count */
Count = *(CmdStream++);
/* Move to the next command and get the value to write */
ShortValue = *(CmdStream++);
/* Add the base to the port */
ShortPort = PtrToUlong(ShortPort) + (PUSHORT)Base;
/* Move to next command */
CmdStream++;
/* Make sure we have data */
if (!ShortValue) continue;
/* Loop the cmd array */
for (; Count; Count--, CmdStream++)
{
/* Get the byte we're writing */
ShortValue += (*CmdStream) << 8;
/* Write USHORT to the port */
WRITE_PORT_USHORT(ShortPort, ShortValue);
}
break;
case 1:
/* The port is what is in the stream right now. Add the base too */
Port = *CmdStream + Base;
/* Move to the next command and get the count */
Count = *++CmdStream;
/* Move to the next command and get the index to write */
Index = (UCHAR)*++CmdStream;
/* Move to next command */
CmdStream++;
/* Loop the cmd array */
for (; Count; Count--, Index++)
{
/* Write the index */
WRITE_PORT_UCHAR(Port, Index);
/* Get the byte we're writing */
Value = (UCHAR)*CmdStream;
/* Move to next command */
CmdStream++;
/* Write UCHAR value to the port */
WRITE_PORT_UCHAR(Port, Value);
}
break;
case 2:
/* The port is what is in the stream right now. Add the base too */
Port = *CmdStream + Base;
/* Read the current value and add the stream data */
Value = READ_PORT_UCHAR(Port);
Value &= *CmdStream++;
Value ^= *CmdStream++;
/* Write the value */
WRITE_PORT_UCHAR(Port, Value);
break;
default:
/* Unknown command, fail */
return FALSE;
}
}
else if (Major != 0xF0)
{
/* Unknown major function, fail */
return FALSE;
}
/* Get the next command */
Cmd = *CmdStream;
}
/* If we got here, return success */
return TRUE;
}
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