Notes in Assembly Language Flashcards
How many columns does a typical video screen have
80
How many rows does a typical video screen have?
25
Code for clearing screen
MOV AX,3
INT 10H
MOV AH,0 (0000)
Video Mode
MOV AH,1 ;(0100)
Single Character Input
MOV AH,2 ;(0200)
Single Character Output
MOV AH,6 ;(0600)
Monitor Screen Processing
MOV AH,8 ;(0800)
Single Character Input No Echo
MOV AH,9 ;(0900)
String Output
MOV AH,10 ;(0A00)
String Input
How many colors can background display?
8
How many colors can be used as text color?
16
What does the msb of the background color represent?
Blinking
What does the msb of the text color represent?
Intensity
Is used to compare character data, as well as, numeric data fields
CMP
The main use is in decision making in conjunction with conditional jump instructions
CMP
These are instructions that transfer control depending on the setting of CMP instruction whether a certain condition is met or not.
Conditional Jump
Is considered an unconditional jump instruction because the machine always executes it
JMP
Make it possible to break a large program down into smaller pieces so that each piece can be shown to work correctly without reference to any of the others
Procedure
Used for filling in time or filling space on tape when there is no data
NUL (null)
Used when there is need to call human attention
BEL (bell)
Indicates that the code combinations, which follow, shall be interpreted as outside of the standard character set until SHIFT IN character is reached
SO (Shift Out)
Used to obliterate unwanted characters
DEL (delete)
A nonprinting used to separate words, or to move the printing mechanism or display cursor forward by one position
SP (space)
A character which shall change the meaning of one or more contiguously following characters.
DLE (Data Link Escape)
It can provide supplementary controls, or permits the sending of data characters having any bit combination
DLE (Data Link Escape)
Character for the control of auxiliary devices or special terminal features
Device Controls
Indicates that the data which precedes it in message or black, should be disregarded
CAN (cancel)
Indicates the physical end card, tape or other medium, or the end of the required or used portion of the medium
EM (End of Medium)
Substitute for a character that is found to be erroneous or invalid
SUB (Substitute)
A character intended to provide code extension in that it gives a specified number of continuously following characters an alternate
ESC (Escape)
Indicates movement of the printing mechanism or display cursor backwards one position
BS (Backspace)
Indicates movement of the printing mechanism or display cursor to the next pre assigned “tab” or stopping position
HT (Horizontal Tab)
Indicates movement of the printing mechanism or display cursor to the start of the next line
LF (Line Feed)
Indicates movement of the printing mechanism or display cursor to the next series of pre-assigned printing lines
VT (Vertical Tab)
Indicates movement of the printing mechanism or display cursor to the starting position of the next page, form or screen
FF (Form Feed)
Indicates movement of the printing mechanism or display cursor to the starting position of the same line
CR (Carriage Return)
Used to indicate the start of a heading, which may contain address or routing information
SOH (Start of Heading)
Used to indicate the start of the text and also indicates the end of the heading
STX (Start of Text)
Used to terminate the text, which was started was started with STX
ETX (End of Text)
Indicates the end of a transmission, which included one or more “text’s” with their headings
EOT (End of Transmission)
A request for a response from a remote station
ENQ (Enquiry)
A character transmitted by a receiving device as an affirmation response to sender
ACK (Acknowledgement)
A character transmitted by a receiving device as a negative response to polling messages
NAK (Negative Acknowledgement)
