MS-DOS uses INT 21H for its main API functions which provide a low-level is the assembly code to transfer data from one file to other using INT 21H?. INT is an assembly language instruction for x86 processors that generates a software interrupt. For example, INT 21H will generate the software interrupt 0x21 (33 in decimal), causing the function pointed to by the 34th vector in the interrupt. int 21h Dos Interrupt. Int 21h is a common function. The INT 21H instruction in is a software interrupt to vector 21H. It is used for input/output operations.
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I’m new to learning assembly language, and I’m wondering what the command int 21h means. It is therefore entirely possible to use a far-call instruction to start the interrupt-function manually after pushing the flag register. Depending on the context, compileror assemblera software interrupt number is often given as a hexadecimal value, sometimes with a prefix 0x or the suffix h.
For example, 21y 21H 808 generate the software interrupt 0x21 33 in decimalcausing the function pointed to by the 34th vector in the interrupt table to be executed, which is typically a DOS API call. When generating a software interrupt, the processor calls one of the functions pointed to by the interrupt address table, which is located in the first bytes of memory while in real mode See Interrupt vector.
Since the dedicated 0xCC opcode has some desired special properties for debugging, which are not shared by the normal two-byte opcode for an INT 3, assemblers do not normally generate the generic 0xCD 0x03 opcode from mnemonics.
Philip Kirkbride 7, 26 82 It comes under type 21h of various interrput tables, hence the lines of code goes like these as you mentioned. 21g in advance for your answer.
INT is an assembly language instruction for x86 processors that generates a software interrupt. This simply means that you are using function 01h of the Interrupt type Email Required, but never shown.
int 21h Dos Interrupt
What does “int 21h” mean in Assembly? – Stack Overflow
Other INT instructions are encoded using two bytes.
INT X where X is the software interrupt that should be generated