This document provides a summary of a lecture on computer organization and assembly language. It discusses the BIOS INT 10H interface, which is burned into the ROM and used to perform functions like clearing the screen, changing the cursor position, and changing screen colors. It describes the monitor screen organization in text mode as 80 columns by 25 rows. It also covers video modes, pixel resolutions and colors for CGA graphics cards, including the 80x25 text mode using 4k bytes of video RAM, the 320x200 mode using 6400 pixels and 4 colors, and the 640x200 mode using 12800 pixels in black and white. It concludes with an overview of directly programming pixels using INT 10H functions.

1. COMPUTER ORGANIZATION
& ASSEMBLY LANGUAGE
LECTURE ON 10H WEEK 13 PRACTICAL
BY MUHAMMAD JAFER
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2. INT 10H
• Burned into ROM of BIOS
• Associated with monitor screen
• Perform different function based upon value in AH
• Function Performed are
• Clearing Screen
• Change the cursor position
• Change the screen color
• Draw line on screen
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3. MONITOR SCREEN IN TEXT MODE
• 80 columns & 25 rows
• 80 characters wide by 25 character long
• 80 column = 00 to 79
• 25 rows= 00 to 24
• First column is at 00,00
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4. CLEARING SCREEN
• AH=06
• AL=00
• BH=07
• CX=0000
• DH=24
• DL=79
• INT 10H
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5. SET CURSOR LOCATION
• AH=02
• BH=00
• DH=24
• DL=59
• INT 10H
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6. GET CURSOR LOCATION
• AH=03
• BH=00
• INT 10H
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7. VIDEO MODES
• AH=00
• AL=VIDEO MODE
• VIDEO MODE = TEXT MODE & RESOLUTION
• Attribute Byte = Associated with Each Character on Screen
• MONOCHROME
• Black & White
• D0 ~ D2 = Foreground Intensity
• D3= 1/0 High or Normal Intensity
• D4 ~ D6 = Background Intensity
• D7 = nonBlicking / Blicking Intensity
• CGA
• Color Graphics Adapter
• D0 ~ D2 = RGB Foreground
• D3= Foreground Intensity
• D4 ~ D6 = RGB Background
• D7 = nonBlicking / Blicking Intensity
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8. PIXEL RESOLUTIONS & COLOR
• Graphical Mode related to Pixel
• Two Important Things about Pixels
• Location
• Attribute
• Stored In Video RAM
• Increase in Pixel = Increase in Memory Required to store
• CGA = Max 16K bytes (Design)
• There are three modes of CGA
• Text mode of 80 * 25 Characters
• Graphical mode of 320 * 200 Resolution
• Graphical mode of 640 * 200 Resolution
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9. 80 * 25 CHARACTERS
• 2k bytes = 80 * 25
• Total 4k bytes
• 2k = locations
• 2k = attributes
• 4 pages of data supporting
• Each Page = 1 Screen
• 16 colors supported
• AL = 03 & AH = 00
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10. 320 * 200 RESOLUTION
• 6400 Pixels = 320 * 200
• 128 bits of Videos Ram
• 2 bits for Color
• 1 bits for Location
• 4 colors supported
• AL = 04 & AH = 00
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11. 640 * 200 RESOLUTION
• 12800 Pixels = 620 * 200
• 128 bits of Videos Ram
• 1 bits for Color
• 1 bits for Location
• Black & White supported
• AL = 06 & AH = 00
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12. PIXEL PROGRAMMING
• AH = OCH
• CX = X-Coordinate
• DX = Y-Coordinate
• BH = Page Number
• AL = Color
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13. PIXEL PROGRAMMING
• AH = OCH
• CX = X-Coordinate
• DX = Y-Coordinate
• BH = Page Number
• AL = Color
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14. CHAPTER REVIEW
• The x86 PC Assembly Language, Design &
Interfacing
• Chapter # 4
• BIOS INT 10H PROGRAMMING
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