StrNCpyAsm, Assembly Language

Assignment Help:
;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

Related Discussions:- StrNCpyAsm

Write a assembly language subroutine, Write a M68000 assembly language subr...

Write a M68000 assembly language subroutine MULSUM that takes an array named A containing n bytes of positive numbers, and fills two arrays, array B containing n

Assebmly code, You have to write a subroutine (assembly language code using...

You have to write a subroutine (assembly language code using NASM) for the following equation.

Instructions, Difference between div and idiv

Difference between div and idiv

Can you write this Program for me please? , $NOMOD51 $NOSYMBOLS ;**********...

$NOMOD51 $NOSYMBOLS ;***************************************************************************** ; Spring 2013 Project ; ; FILE NAME : Project.ASM ; DATE : 3/30/20

Rep-string manipulation instruction-microprocessor, REP : Repeat Instructi...

REP : Repeat Instruction Prefix :- This instruction is utilized as a prefix to other instructions. The instruction in which the REP prefix is provided, is executed repetitively

Memory address decoding-microprocessor, Memory Address Decoding Binary ...

Memory Address Decoding Binary Decoders - Decoders have 2n-inputs and n outputs, each input combination results in a single output line contain a 1, and all other lines contain

Avr, how to code

how to code

Program to convert decimal to binary number, Program is written but has err...

Program is written but has errors returning values from the procedure.

Xml, Write the structure of For…Next loop in VB.Net and also write a progra...

Write the structure of For…Next loop in VB.Net and also write a program to print integers from 1 to 10 on the console.

Cache controller-microprocessor, Cache controller The cache controller ...

Cache controller The cache controller is the mind of the cache.  Its responsibilities include:  performing the  snarfs and snoops, updating the  TRAM  and SRAM and implementing

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd