What does INT 21h mean in assembly language?
int 21h means, call the interrupt handler 0x21 which is the DOS Function dispatcher. the “mov ah,01h” is setting AH with 0x01, which is the Keyboard Input with Echo handler in the interrupt.
What is the function of INT 21h with AH 01h?
INT 21H is what makes a call into MS DOS. The 01H in the AH register indicates what DOS command to execute which, in this case, is to read a character from STDIN. The result will end up in the AL register.
What does Ah mean in assembly language?
accumulator
Registers and the CPU
| AH,AL,AX | accumulator |
|---|---|
| BH,BL,BX | base register |
| CH,CL,CX | count register |
| DH,DL,DX | data register |
What does INT 21h accomplishes if ah contains 4c H?
on ah=4ch int 21h , the program will terminate control to the operating system. (end the program) And int 21h is a dos interrupt.
What is the function of 4Ch under INT 21h?
INT 21h function 4Ch is preferred. Action: Reads a character from the standard input device and echoes it to the standard output device. If no character is ready it waits until one is available.
What is Int 3 in assembly language?
INT3. The INT3 instruction is a one-byte-instruction defined for use by debuggers to temporarily replace an instruction in a running program in order to set a code breakpoint. The more general INT XXh instructions are encoded using two bytes.
What is 10H assembly language?
INT 10h, INT 10H or INT 16 is shorthand for BIOS interrupt call 10hex, the 17th interrupt vector in an x86-based computer system. The BIOS typically sets up a real mode interrupt handler at this vector that provides video services.
What is DB 10 13 assembly language?
As Internal Server Error’s comment indicates 10 is the ASCII control code for line feed while 13 is the code for carriage return. The line feed control code moves the cursor to the next line, while the carriage return code moves the cursor to the start of line.
What is the function of 4Ch of int 21h?
What is INT instruction in assembly?
INT is an assembly language instruction for x86 processors that generates a software interrupt. It takes the interrupt number formatted as a byte value. When written in assembly language, the instruction is written like this: INT X. where X is the software interrupt that should be generated (0-255).
What is the function of 4Ch under INT 21H?
What is the meaning of INT 21h/AH=7?
INT 21h / AH=7 – Character input without echo to AL. if there is no Character in the keyboard buffer, the function waits until any key is pressed. Character input without echo to AL. INT 21h / AH=9 – output of a string at DS:DX. String must be terminated by ‘ $ ‘. output of a string at DS:DX. String must be terminated by ‘ $ ‘.
How to display string with INT 21h AH=09h?
To display this captured string with int 21h, ah=09h, you will have to replace the last chr (13) by ‘$’, then make DX to point to the valid characters that start at the third byte :
What does INT 21h mean in an interrupt?
Show activity on this post. int 21h means, call the interrupt handler 0x21 which is the DOS Function dispatcher. the “mov ah,01h” is setting AH with 0x01, which is the Keyboard Input with Echo handler in the interrupt. See: Show activity on this post.
What are the control characters for the INT 21h Function?
Many INT 21h functions act upon the following control characters: 08h – Backspace (moves one column to the left) 09h – Horizontal tab (skips forward n columns) 0Ah – Line feed (moves to next output line) 0Ch – Form feed (moves to next printer page) 0Dh – Carriage return (moves to leftmost output column) 1Bh – Escape character