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Advanced Features of Screen Processing

Advanced Features of Screen Processing. Suthida Chaichomchuen std@kmitnb.ac.th. BIOS INT 10H. 00H : Set video mode 01H : Set cursor size 02H : Set cursor position 03H : Read cursor position 04H : Read light pen position 05H : Select active page 06H : Scroll up screen

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Advanced Features of Screen Processing

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  1. Advanced Features of Screen Processing Suthida Chaichomchuen std@kmitnb.ac.th

  2. BIOS INT 10H • 00H : Set video mode • 01H : Set cursor size • 02H : Set cursor position • 03H : Read cursor position • 04H : Read light pen position • 05H : Select active page • 06H : Scroll up screen • 07H : Scroll down screen • 08H : Read attribute/character • 09H : Display attribute/character • 0AH : Display character

  3. BIOS INT 10H • 0BH : Set color palette • 0CH : Write pixel dot • 0DH : Read pixel dot • 0EH : Write teletype • 0FH : Get current video mode • 11H : Character generator • 12H : Select alternative routine • 13H : Display character string • 1BH : Return state information • 1CH : Save/restore video status

  4. Video Adapters • MDA : Monochrome display adapter • CGA : Color graphics adapter • EGA : Enhanced graphics adapter • MCGA : Multicolor graphics array • VGA : Video graphics array

  5. Video Display • Video controller • generate the monitor’s scan signals • Video BIOS • Interface to the video adapter • setting cursor • displaying characters • Video display area • contain the information for display

  6. Attribute Byte • Bit 7 (BL) • set blinking • Bits 6-4 • determine the screen background • Bit 3 (I) • set high intensity • Bit 2-0 • determine the foreground

  7. Screen Pages • Text mode • Page 0 - 3 • Begin address • B800[0] : Page 0 • B900[0] : Page 1 • BA00[0] : Page 2 • BB00[0] : Page 3 • Amount memory for each page • 80 x 25 x 2 = 4000 bytes (4K)

  8. INT 10H Function 00H • Set video mode • AH = 00H • AL = video mode value • 00 : 25 x 40 mono • 01 : 25 x 40 color • 02 : 25 x 80 mono • 03 : 25 x 80 color • 07 : 25 x 80 mono

  9. INT 10H Function 00H • Example • MOV AH,00H • MOV AL,03H • INT 10H

  10. INT 10H Function 01H • Set cursor size • AH = 01H • CH (bit 4-0) = top of cursor • CL (bit 4-0) = bottom of cursor • Cursor size • 0:14 - VGA • 0:13 - EGA • 0:7 - CGA

  11. INT 10H Function 01H • Example • MOV AH,01H • MOV CH,00 • MOV CL,14 • INT 10H

  12. INT 10H Function 02H • Set cursor position • AH = 02H • BH = page number (0-3) • 0 : default • DH = row • DL = column

  13. INT 10H Function 02H • Example • MOV AH,02H • MOV BH,00 • MOV DH,12 • MOV DL,30 • INT 10H

  14. INT 10H Function 03H • Read cursor position • Determine the Row, Column, cursor Size • AH = 02H • BH = page number • Values return of operation • AX, BX : unchanged • CH : starting scan line • CL : ending scan line • DH : row • DL : column

  15. INT 10H Function 03H • Example • MOV AH,03H • MOV BH,00 • INT 10H • MOV AH,02H • INC DL • INT 10H

  16. INT 10H Function 05H • Select active page • AH = 05H • AL = page number • Example • MOV AH,05H • MOV AL,page# • INT 10H

  17. INT 10H Function 06H • Scroll up screen • AH = 06H • AL = number of rows (00 for full screen) • BH = attribute • CX = starting row : column • DX = ending row : column

  18. INT 10H Function 06H • Example • MOV AH,06H • MOV BH,61H • MOV CX,0000H • MOV DX,184FH • INT 10H

  19. INT 10H Function 07H • Scroll down screen • AH = 07H • AL = number of rows (00 for full screen) • BH = attribute • CX = starting row : column • DX = ending row : column

  20. INT 10H Function 08H • Read attribute/character at cursor position • AH = 08H • BH = page number • Values return • AL = character • AH = attribute of character • Example • MOV AH,08H • MOV BH,00 • INT 10H

  21. INT 10H Function 09H • Display attribute/character at cursor position • AH = 09H • AL = ASCII character to be displayed • BH = page number • BL = attribute • CX = count

  22. INT 10H Function 09H • Example • MOV AH,09H • MOV AL,01H • MOV BH,00 • MOV BL,16H • MOV CX,60 • INT 10H

  23. INT 10H Function 0AH • Display character at cursor position • AH = 0AH • AL = ASCII character to displayed • BH = page number • CX = count

  24. INT 10H Function 0AH • Example • MOV AH,0AH • MOV AL,char • MOV BH,page# • MOV CX,repetition • INT 10H

  25. INT 10H Function 0EH • Write teletype • AH = 0EH • AL = ASCII character to displayed • 08H : backspace • 07H : bell • 0DH : carriage return • 0AH : line feed • BH = page number • BL = foreground color

  26. INT 10H Function 0EH • Example • MOV AH,0EH • MOV AL,char • MOV BH,page# • MOV BL,color • INT 10H

  27. INT 10H Function 0FH • Get current video mode • AH = 0FH • Values return • AL = current video mode • AH = characters per line (20, 40 or 80) • BH = current page number • Example • MOV AH,0FH • INT 10H

  28. INT 10H Function 12H • Select alternative screen routine • AH = 12H • Values return • BH = 00H for color, 01H for monochrome • BL = 00H for 64K, 01H for 128K, 02H for 192K, 03H for 256K • CH = adapter bits • CL = switch setting • Example • MOV AH,12H • INT 10H

  29. INT 10H Function 13H • Display character string • AH = 13H • AL = subfunctions (00, 01, 02 or 03) • BH = page number • BL = screen attribute • BP = address of string in ES:BP • CX = length of string • DX = starting location on screen

  30. INT 10H Function 13H • Four subfunctions in AL • 00 : display attribute and string; do not advance cursor • 01 : display attribute and string; advance cursor, • 02 : display character and then attribute; do not advance cursor • 03 : display character and then attribute; advance cursor

  31. INT 10H Function 13H • Example • MOV AH,13H • MOV AL,subfunction • MOV BH,page# • MOV BL,attribute • LEA BP,address • MOV CX,length • MOV DX,screen • INT 10H

  32. Using Graphics Mode • Set graphic mode by use function 00H • Mode number in AL • 04H - 06H • 0DH - 13H • used Pixels to generate color patterns • Example • MOV AH,00H • MOV AL,12H • INT 10H

  33. INT 10H Function 04H • Read light pen position • AH = 04H • Values return • AH = 0 - not triggered, 1 - triggered • DH = row • DL = column • CH:BX = pixel location

  34. INT 10H Function 0BH • Set color palette • AH = 0BH • BH = 00 or 01 • determine the purpose of BL

  35. INT 10H Function 0BH • BH = 00 • select the background color • BL = color value in bit 0-3 • Example • MOV AH,0BH • MOV BH,00 • MOV BL,04 • INT 10H

  36. INT 10H Function 0BH • BH = 01 • select the palette for graphics • BL = the palette 0 or 1 • Example • MOV AH,0BH • MOV BH,01 • MOV BL,00 • INT 10H

  37. INT 10H Function 0CH • Write pixel dot • AH = 0CH • AL = color of the pixel • BX = page number (VGA/EGA) • CX = column • DX = row

  38. INT 10H Function 0CH • Example • MOV AH,0CH • MOV AL,03 • MOV BH,00 • MOV CX,200 • MOV DX,50 • INT 10H

  39. INT 10H Function 0DH • Read pixel dot • AH = 0DH • BX = page number (VGA/EGA) • CX = column • DX = row • Value return • AL = pixel color

  40. INT 10H Function 10H • Set palette registers • AH = 10H • AL = subfunction code (00-03)

  41. INT 10H Function 10H • Subfunction code in AL • 00 : set a palette register • BH = the value to set • BL = the register to set • 01 : set the overscan register • BH = the value to set • 02 : set all palette registers and overscan • bytes 0-15 = palette values • byte 16 = overscan value • 03 : Toggle the intensity/blinking bit • BL = 00 enables intensity • BL = 01 enables blinking

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