What does int 21h do in 8086?
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What does int 21h do in 8086?
3 Answers. INT 21H will generate the software interrupt 0x21 (33 in decimal), causing the function pointed to by the 34th vector in the interrupt table to be executed, which is typically an MS-DOS API call.
What is function of the MOV 21h?
INT 21H: It is called the DOS function call for keyboard operations follow the function number.
What is the action of function 01h of INT 21h?
INT 21h – The general function despatcher
| 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. I/O can be re-directed, but prevents detection of OEF. |
|---|---|
| On entry: | AH = 01h |
| Returns: | AL = 8 bit data input |
What is mov ah in assembly language?
mov ah,4ch is the first line of assembler code. The value 4C in hexadecimal is stored in the register AH. int 21h is the second line of assembler code. The software interrupt 21h is called. This interrupt, when given the value of 4ch in AH (as is the case here), causes the program to exit immediately.
For what purpose these lines are used mov ax data mov ds ax?
mov ax,@data ; Initalize DS mov ds,ax … It is a directive that is used by 2 tools: assembler & loader • Assembler : Uses it to know when to stop reading from . ASM file – Any statements after END are ignored. Any statements after END are ignored.
What is the significance of INT 21h and MOV AH 4Ch while programming 8086 in DOS?
In MS-DOS, invoking interrupt 21h while AH = 4Ch causes the current process to terminate and uses the value of register AL as the exit code of the process.
What is the function of 4Ch and 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.