CS 2650 - Computer Architecture

Assembler Program #2
Due 6April, 2009 prior to class

Display your name, the System Date, and the System Time, centered in the display.

John Locke 04/03/2009 16:23:42

Be careful to follow the steps exactly so as not to completely erase the hard disk or<worse>!

1.  Open Notepad or another text editor
2.  Key in the basic NASM template as in assignment #1.
3.  Write Assembler code to:

• a.  Clear the screen using INT 10H service 06H
• b.  Display your  name on row 13, centered horizontally on the screen. 
  Use INT 10H service 13H. 
  Make sure you load register CX with the number of characters in your stored name.  
  Use display page 00H.
  
• c.  Get, convert and display the current system date on the row below your name, also centered. 
  Use INT 1AH function 04H to retrieve the BIOS date. 
  Create code to convert the BCD date from the registers to ASCII in memory. 
  (BCD can be converted to ASCII using SHR, AND, and ADD and MOV instructions).
  Use INT 10H service 13H to display the converted date.
  
• d.  Get, convert and display the current system time on the next row, also centered. 
  Use INT 1AH service 02H to retrieve the BIOS time. 
  Create code to convert the BCD time fields from the registers to ASCII values in memory.
  Use INT 10H service 13H to display the converted time under the date.
  
• e.  Make sure that you have an INT 20H as your last executable command.

4.  Save your program as CS2650P2.ASM to the same folder as NASMW.EXE and EXEBIN.MAC

5.  Compile your program by typing at the command line: 
NASMW CS2650P2.ASM -oCS2650P2.COM

6.  If you have errors on compile, correct them and then recompile as in #5

7.  Thoroughly test your program before submitting it.
8.  Upload your program (both .asm and .com files) using the Web Uploader by the due date 
  

Input Registers
 AH  06h
 AL  Number of lines to scroll (if zero, entire windows is blanked)
 BH  Attribute used for blanked area (Attribute byte defined below)
 CH  Row, upper left corner
 CL  Column, upper left corner
 DH  Row, lower right corner
 DL  Column, Lower right corner

Output Registers
 None

Input Registers
 AH  13h
 AL  Write mode   Use 00h
 BH  Video Page  Use 00h
 BL  Attribute byte  (Attribute byte defined below)
 CX  Length of String
 DH  Row at which to write string
 DL  Column at which to write string
 ES:BP Pointer to string

Output Registers
 None

Attribute Byte breakdown

Bit 0 - Blue component of foreground color
Bit 1 - Green component of foreground color
Bit 2 - Red component of foreground color
Bit 3 - Intensity component of foreground color
Bit 4 - Blue component of background color
Bit 5 - Green component of background color
Bit 6 - Red component of background color
Bit 7 - Intensity component of background color