/// <summary>
/// ADC portion of the TextMode class setup. For X86, this function
/// first locates the addresses of CRT controllers using color (EGA/CGA)
/// or alternatively monochrome (MDA) display standards. Finally it
/// determines the width and height of the text buffer.
/// </summary>
/// <reference>http://www.cknow.com/refs/VideoDisplayStandards.html</reference>
public static void Setup()
{
// Find CRT controller addresses
if ((IO.ReadByte(IO.Port.EGA_graphics_1_position_register) & 1) == 1)
{
// CGA/EGA color text mode
CRT_index_register = IO.Port.CGA_CRT_index_register;
CRT_data_register = IO.Port.CGA_CRT_data_register;
// HACK!!
videoMemory.address = (byte *)0xB8000;
videoMemory.length = 0x4000; // CGA has 16kb video memory
//videoMemory = Architecture.ResourceManager.RequestMemoryMap(0xB8000, 0x4000);
// ideally we'd poll how much video memory
// we can use, but we can't so we're
// being conservative and only use 16kb.
bytePerChar = 2;
colorMode = true;
haveBuffer = true;
}
else
{
// MDA monochrome text mode
CRT_index_register = IO.Port.MDA_CRT_index_register;
CRT_data_register = IO.Port.MDA_CRT_data_register;
// HACK!!
videoMemory.address = (byte *)0xB0000;
videoMemory.length = 0x1000; // MDA has 16kb video memory
//videoMemory = Architecture.ResourceManager.RequestMemoryMap(0xB0000, 0x1000);
bytePerChar = 1;
colorMode = false;
haveBuffer = false;
}
// read the width
width = HardwareCommand(CRT_Indices.horizontal_displayed) + 1;
// this returns a funny number... what am i doing wrong here?
//height = HardwareCommand(CRT_Indices.vertical_displayed) + 1;
height = 25;
scanline = (uint)(width * bytePerChar);
if (haveBuffer)
{
bufferHeight = (int)(
videoMemory.Length
/ scanline) - 1;
}
else
{
bufferHeight = height;
}
bufferSize = (uint)bufferHeight * scanline;
readY = 0;
writeY = 0;
for (int x = 0; x < EntryModule.MaxTextAttributeSlots; x++)
{
savedAttributes [x] = 0xFF;
}
}
/// <summary>
/// ADC portion of the TextMode class setup. For X86, this function
/// first locates the addresses of CRT controllers using color (EGA/CGA)
/// or alternatively monochrome (MDA) display standards. Finally it
/// determines the width and height of the text buffer.
/// </summary>
/// <reference>http://www.cknow.com/refs/VideoDisplayStandards.html</reference>
public static void Setup ()
{
// Find CRT controller addresses
if ((IO.ReadByte (IO.Port.EGA_graphics_1_position_register) & 1) == 1) {
// CGA/EGA color text mode
CRT_index_register = IO.Port.CGA_CRT_index_register;
CRT_data_register = IO.Port.CGA_CRT_data_register;
// HACK!!
videoMemory.address = (byte*)0xB8000;
videoMemory.length = 0x4000; // CGA has 16kb video memory
//videoMemory = Architecture.ResourceManager.RequestMemoryMap(0xB8000, 0x4000);
// ideally we'd poll how much video memory
// we can use, but we can't so we're
// being conservative and only use 16kb.
bytePerChar = 2;
colorMode = true;
haveBuffer = true;
} else {
// MDA monochrome text mode
CRT_index_register = IO.Port.MDA_CRT_index_register;
CRT_data_register = IO.Port.MDA_CRT_data_register;
// HACK!!
videoMemory.address = (byte*)0xB0000;
videoMemory.length = 0x1000; // MDA has 16kb video memory
//videoMemory = Architecture.ResourceManager.RequestMemoryMap(0xB0000, 0x1000);
bytePerChar = 1;
colorMode = false;
haveBuffer = false;
}
// read the width
width = HardwareCommand (CRT_Indices.horizontal_displayed) + 1;
// this returns a funny number... what am i doing wrong here?
//height = HardwareCommand(CRT_Indices.vertical_displayed) + 1;
height = 25;
scanline = (uint) (width * bytePerChar);
if (haveBuffer)
bufferHeight = (int) (
videoMemory.Length
/ scanline) - 1;
else
bufferHeight = height;
bufferSize = (uint) bufferHeight * scanline;
readY = 0;
writeY = 0;
for (int x = 0; x < EntryModule.MaxTextAttributeSlots; x++)
savedAttributes [x] = 0xFF;
}
