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NEW XBIOS CALLS FOR THE ATARI TT
--------------------------
NEW XBIOS CALLS FOR THE TT
--------------------------
Warning: Use of these calls is restricted to the TT only. For compatibility
with other Atari computers use of these calls should be limited to those
applications which will require porting due to other incompatibility.
(80) _EsetShift
WORD _EsetShift(shftMode)
WORD shftMode
Set the TT shift mode register to shftMode.
Bit assignments
|S--H-MMM----BBBB|
| | | | | |
| | | | ------- Bank
| | -------------- Mode
| | 000 320x200x4
| | 001 640x200x2
| | 010 640x400x1
| | 100 640x480x4
| | 110 1280x960x1
| | 111 320x480x8
| ---------------- Hyper Mono
------------------- Sample & Hold
call always returns old shift mode register value.
Note: For more information on Hyper Mono see: _EsetGray. Also
the values returned by Getrez() correspond to the Mode
information given here. Also it is easier to change
individual elements of this register using the specialized
calls below. They should be used whenever possible.
(81) _EgetShift
WORD _EgetShift()
Returns the current shift mode register value.
(82) _EsetBank
WORD _EsetBank(bankNum)
WORD bankNum;
Set bank number (0-15) for active TT color Lookup Table.
This call also maps the current bank's colors to the old
ST color lookup Table. The bank is set imediately.
Function always returns old bankNum. If 'bankNum' is
negative, the hardware register is not altered.
(83) _EsetColor
WORD _EsetColor(colorNum, color)
WORD colorNum, color;
Set the absolute entry 'colorNum' in the TT color LookUp
table to the given color. Color is set imediately.
Function always returns the old color. If 'color' is
negative, the hardware register is not altered.
(84) _EsetPalette
VOID _EsetPalette(colorNum, count, palettePtr)
WORD colorNum, count;
LONG palettePtr;
Set the contents of a contiguous set of TT hardware
palette registers with the words pointed to by 'palettePtr'.
'palettePtr' must fall on a word boundary. The set of
registers loaded begins with LUT register 'colorNum'
and extends for 'count' words. The function sets the
pallete immediately.
(85) _EgetPalette
VOID _EgetPalette(colorNum, count, palettePtr)
WORD colorNum, count;
LONG palettePtr;
Copy the contents of of a contiguous set of TT hardware
color LookUp Table registers starting with register
'colorNum' into the area pointed to by 'palettePtr'.
'count' words are transfed into the area. 'palettePtr'
must fall on a word boundary.
(86) _EsetGray
WORD _EsetGray(switch)
WORD switch;
Set the manner in which the color LookUp Table data is
interpreted by the display hardware. A 'switch' value of
zero directs the display hardware to interpret the LUT
data as color, 4 bits for each of the three components.
With a non-zero 'switch' value, the upper byte of the LUT
entry is ignored and the lower byte alone represents one
of 256 gray levels. Function always returns the old switch
switch value (a non-zero value means 'switch' is set).
On input if 'switch' is set to a negative value, the hardware
register is not altered.
(87) _EsetSmear
WORD _EsetSmear(switch)
WORD switch;
Set the video smear mode. A 'switch' value of zero
indicates normal display mode while a non-zero value
instructs the display hardware to repeat (smear) the last
non-zero color encountered whenever zero values are retrieved.
Function always returns the old switch value (a non-zero value
means 'switch' is set). On input, if 'switch' is set to a
negative value, the hardware register is not altered.
