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

Lab Assignment, 1) Write an 80x86 assembly language program in EXE file for...

1) Write an 80x86 assembly language program in EXE file format to do the following tasks: a) Open and read the contents of a file into memory (use at least 1 kB). b) Sort the li

Assembling a program-microprocessor, Assembling a program Microsoft Ass...

Assembling a program Microsoft Assembler MASM is one of the simple to use and famous assemblers.  All the references and discussions in this section are belonging to the MASM.

8279 keyword /display controller-microprocessor, 8279 Keyword /Display Cont...

8279 Keyword /Display Controller : Figure shows the structure of 8279 and its interface to the bus. Addressing is according to the table given below. CS        RD

Read file in 8086, Write a procedure to read a text file and copy its cont...

Write a procedure to read a text file and copy its contents to another text file using 8086 assembly language .

Implement an assembly language program, A good starting point for your prog...

A good starting point for your program is the toupper.asm program shown in class. It already queries the user for input and sets up a loop that looks at each character of the input

Assembly language programming, Write an assembly language program that defi...

Write an assembly language program that defines symbolic constants for all seven days of the week

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

Assembly language programs-microprocessor, Assembly Language Example Progra...

Assembly Language Example Programs We studied the entire instruction set of 8086/88, pseudo-ops and assembler directives. We have explained the process of entering an assembly

Interrupt-microprocessor, Interrupt When the CPU detects an interrupt s...

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

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