StrNCpyAsm, Assembly Language

;StrNCpyAsm - copy zero terminated string2 to zero terminated string1,
; but copy no more than count (parameter) characters
; or the length of string2, whichever comes first
; entry: - addStr1 contains the address of string1
; - addStr2 contains the address of string2
; - count contains the max number of characters to copy
; exit: NONE (no return value so do not use edi to return an address)
; Note: StrNCpyAsm does not zero terminate the copied string
; unless the 0 is within count characters copied.
; example1: char str1[]= {''h'',''e'',''l'',''l'',''o'','' '',''w'',''o'',''r'',''l'',''d'',0};
; char str2[]= {''G'',''o'',''o'',''d'',''-'',''b'',''y'',''e'',0};
; StrNCpyAsm(str1,str2,4);//terminating 0 not copied since only 4 characters copied
; ;//and terminating 0 not within the 4 characters
; after copy str1 contains: ''G'',''o'',''o'',''d'',''o'','' '',''w'',''o'',''r'',''l'',''d'',0
; example2: use str1 and str2 from example1
; StrNCpyAsm(str1,str2,9); //terminating 0 copied since terminating 0
; //within 9 characters copied
; str1 contains: ''G'',''o'',''o'',''d'',''-'',''b'',''y'',''e'',0,''l'',''d'',0
; example3: use str1 and str2 from example1
; StrNCpyAsm(str1,str2,20);//copy 20 characters upto and including 0,
; //whichever comes first
; //only 9 characters including 0 copied
; after copy str1 contains: ''G'',''o'',''o'',''d'',''-'',''b'',''y'',''e'',0,''l'',''d'',0
; The above is how you would call StrNCpyAsm from C++.
; To call StrNCpyAsm from an asm function use:
; push 20 ;max num of characters to copy
; push str2Add ;address of string 2
; push str1Add ;address of string 1
; call StrNCpyAsm
; ;no add esp, 12 needed because stack cleaup automatically done
;Do not use a loop in this function.
;Choose 2 instructions from the following string instructions to use:
; rep, repe, repne, movsb,stosb,cmpsb,scasb
; hint1: use StrLenAsm to get the number of characters in str2
; hint2: the length returned by StrLenAsm does not include terminating 0
; hint3: copy the lesser of the length of the string (including terminating 0)
; or count characters
;copy to ecx the lesser of count or the length of string2 (including terminating 0)
; Please note for the above, you need the length of string2 including terminating 0.
; StrLenAsm returns the length not including terminating 0
;populate esi and edi with the correct values
;clear the direction flag
;use rep and movsb to copy

StrNCpyAsm PROC uses eax esi edi ecx , ;save registers used
addStr1:DWORD, ;address of string1
addStr2:DWORD, ;address of string2
count:DWORD ;max chars to copy
Posted Date: 12/6/2012 11:39:50 PM | Location : United States

Related Discussions:- StrNCpyAsm, Assignment Help, Ask Question on StrNCpyAsm, Get Answer, Expert's Help, StrNCpyAsm Discussions

Write discussion on StrNCpyAsm
Your posts are moderated
Related Questions
Write a procedure to read a text file and copy its contents to another text file using 8086 assembly language .

a pseudo-code to add username and password combination up to a limit of 10

1. The microwave has a clock (hh:mm:ss am/pm) and the user should be able to change the clock at any time. 2. For cooking the user should first enter the time. The user can ente

Interrupt When the CPU detects an interrupt signal, it stops activity of current and jumps to a special routine, known an interrupt handler. This handler then detects why the i

XOR: Logical Exclusive OR: The XOR operation is again carried out in a similar way to the AND and OR operation. The constraint over operands are also similar. The XOR operation pr

Example : Add the contents of the 2000H: 0500H memory location to contents of 3000H: 0600H and store the result in 5000H: 0700H. Solution : Unlike the past example progra

write an assembly program to display triangular star like shape

IRET : Return from ISR:- When an interrupt service routine is called, before transferring control to it, the IP, CSĀ  register and flag registers are stored in the stack to ment

how we can multiply two 8 bit number with rotation

using 8086 assembly language that interchange upper four bits to lower four bits. assume that data store in byte memory and it written back to same location. and assume the data as