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

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

Format of control register-microprocessor, Format of Control Register T...

Format of Control Register The format for the control register is given in Figure. Bit 0 of this register might be one before data may be output  and  bit  two  might be  one

Instructions, Difference between div and idiv

Difference between div and idiv

Program on virtual learning environment, Task One Produce a menu such a...

Task One Produce a menu such as the one below (remember to keep to this specification). M E N U 1, Enter Number 1 2, Enter Number 2 3, Display num1 and num2 4, D

Architecture of 8088-microprocessor, Architecture Of 8088 The register ...

Architecture Of 8088 The register set of 8088 is accurately the same as in to 8086. The architecture of 8088 is also same to 8086 except for 2 changes; a) 8088 has 4-byte instr

Boolean and comparison instructions, what will be the value of EAX after fo...

what will be the value of EAX after following instructions execute? mov bx, 0FFFFh and bx, 6Bh

Convert from C to 8086 assembly language, Trying to convert small programs ...

Trying to convert small programs from C to 8086 assembly language using emu 8086 emulator. I converted to low level C, but struggling with converting to the Assembly language.

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

Pc bus and interrupt system-microprocessor, PC Bus and Interrupt System ...

PC Bus and Interrupt System The PC Bus utilized a bus controller, address latches, and data transceivers (bidirectional data buffers). 1) Bus controller : ( Intel 8288 Bus

Compute the fibonacci sequence - assembly program, Compute the Fibonacci se...

Compute the Fibonacci sequence - assembly program: Problem: Fibonacci   In this problem you will write a program that will compute the first 20 numbers in the Fibonacci sequ

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