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What is the function of INT 21h in 8086?

What is the function of INT 21h 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. This simply means that you are using function 01h of the Interrupt type 21…

What are the dos interrupts?

Interrupt vectors used by DOS

Interrupt vector Description Version
24h Critical error handler address 1.0+
25h Absolute disk read 1.0+
26h Absolute disk write 1.0+
27h Terminate and stay resident 1.0+

What is the function of the INT 21h?

INT 21H (0x21) function 08H (0x08) 09H (0x09) 0AH (0x0A or 10) 0BH (0x0B or 11) INT 21H (0x21) function 08H (0x08) Character input without echo 09H (0x09) Display string 0AH (0x0A or 10) Buffered keyboard input 0BH (0x0B or 11) Check input status 0CH (0x0C or 12) Flush input buffer and then Input

How to call the function AH with 0Ch?

Call with: AH = 0CH AL = number of input to be invoked after resetting buffer (must be 01H, 06H, 07H, 08H or 0AH) If AL = 0AH DS: DX = segment: offset of input buffer Returns: If called with AL = 01H, 06H, 07H, or 08H,

Which is the equivalent of interrupt 21h service 0?

Terminates program execution. This function, equivalent in effect to interrupt 21h service 0 terminates the execution of a program and returns control to DOS, which restores the terminate, ctrl-break and critical-error exit addresses from the PSP, and all files written to by the program must be close before interrupt 20h is called.

What is the output of function 09h in DOS?

Outputs a character to the standard output device. This function outputs to the standard output device the character whose ASCII value in DL. To output an entire string, see function 09h. If a Ctrl-Break (Ctrl-C) is detected, an INT 23h is generated. Waits for a character from ths standard auxiliary device. Checks for ctrl-break and ctrl-c.