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

Flag register-microprocessor, Flag Register : 8086 has a 16-bit flag r...

Flag Register : 8086 has a 16-bit flag register which is divided into 2 parts, viz. (a)machine control flagsand (b)condition code or status flags. The condition code flag regi

Program to add 8-bit series numbers-assembly language, Program: Write a pr...

Program: Write a program to perform addition of a series of 8-bit numbers. The series have 100 (numbers). Solution : In the first program, we have been implemented the add

Operating System, Why is the capability to relocate processes desirable?

Why is the capability to relocate processes desirable?

Stand alone system - assembly language program, Develop an assembly languag...

Develop an assembly language program for the system and simulate it using MPLAB. From this produce a demo program (in Assembly language) that will run on the MatrixMultimedia Devel

Assignment, 1. Write an assembly program that adds the elements in the odd ...

1. Write an assembly program that adds the elements in the odd indices of the following array. Use LOOP. What is the final value in the register? array1 DWORD 10, 20, 30, 40, 50, 6

Relocate program and data, ) What is the difference between re-locatable pr...

) What is the difference between re-locatable program and re-locatable data?

Flowchart, ALP to preform of two 16-bit numbers in register addressing mode...

ALP to preform of two 16-bit numbers in register addressing mode

Entering a program-microprocessor, Entering a Program In this section, ...

Entering a Program In this section, we will explain the procedure for entering a small program on IBM PC with DOS operating system. Assume a program of addition of 2 bytes, as

Div-idiv-arithmetic instruction-microprocessor, DIV: Unsigned Division:- T...

DIV: Unsigned Division:- This instruction performs unsigned division operation. It divides an unsigned word or double word by a 16-bit or 8-bit operand. The dividend might be in t

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