NEW XBIOS CALLS FOR THE ATARI TT

@atari

Published in 

atari

 · 3 years ago

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NEW XBIOS CALLS FOR THE TT 
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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.