Function 11h    Character Generator Routine (EGA and after) 

entry   AH      11h 

		The following functions will cause a mode set, completely 

		resetting the video environment, but without clearing the video 

		buffer. 

	AL      00h, 10h  load user-specified patterns 

			BH      number of bytes per character pattern 

			BL      block to load in map 2 

			CX      count of patterns to store 

			DX      character offset into map 2 block 

			ES:BP   pointer to user table 

		01h, 11h  load ROM monochrome patterns (8 by 14) 

			BL      block to load 

		02h, 12h  load ROM 8 by 8 double-dot patterns 

			BL      block to load 

		03h       set block specifier 

			BL      block specifier 

	       (EGA/MCGA) bits 0,1   = block selected by chars with attribute 

			  bit  3     = 0 

			  bits 2,3   = block selected by chars with attribute 

			  bit  3     = 1 

	       (VGA)      bits 0,1,4 = block selected by attribute bit 3 = 0 

			  bits 2,3,5 = block selected by attribute bit 3 = 1 

		04h,14h   load 8x16 text character set (MCGA, VGA) 

			  The routines called with AL=1x are designed to be 

			  called only immediately after a mode set and are 

			  similar to the routines called with AL=0x, except 

			  that: 

			  Page 0 must be active. 

			  Bytes/character is recalculated. 

			  Max character rows is recalculated. 

			  CRT buffer length is recalculated. 

			  CRTC registers are reprogrammed as follows: 

			  reg09h    bytes/char-1; max scan line (mode 7 only) 

			  reg0Ah    bytes/char-2; cursor start 

			  reg0Bh    0           ; cursor end 

			  reg12h    ((rows+1)*(bytes/char))-1 

			                        ; vertical display end 

			  reg14h    bytes/char  ; underline loc 

			            (* BUG: should be 1 less *) 

 

			The following functions are meant to be called only 

			after a mode set: 

		20h     user 8 by 8 graphics characters (int 1Fh) 

			ES:BP   pointer to user table 

		21h     user graphics characters 

			ES:BP   pointer to user table 

			CX      bytes per character 

			BL      row specifier 

			        0       user set 

			                DL      number of rows 

			        1       14 rows 

			        2       25 rows 

			        3       43 rows 

		22h     ROM 8 by 14 set 

			BL      row specifier 

		23h     ROM 8 by 8 double dot 

			BL      row specifier 

		24h     load 8x16 graphics characters (MCGA, VGA) 

			BL      row specifier 

 

		30h     Get Font Information          (EGA, MCGA, VGA) 

			BH      pointer specifier 

			        0       int 1Fh pointer 

			        1       int 44h pointer 

			        2       ROM 8 by 14 character font pointer 

			        3       ROM 8 by 8 double dot font pointer 

			        4       ROM 8 by 8 DD font (top half) 

			        5       ROM text alternate (9 by 14) pointer 

return  ES:BP   specified pointer value 

	CX      bytes/character 

	DL      character rows on screen 

 

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