A Borland 16-bit example… (you would need 16-bit linker)

//add.c
#include <stdio.h>
int x;
int array[10];
extern void arrayproc(int*,int);
void main(){
int j;
for( j=0;j<10;j++)array[j]=j*100;

arrayproc(array,10);
for( j=0;j<10;j++)printf("%d  ",array[j]);
}

;ap.asm
model small
dataseg
 newline db 0ah,0dh,'$'
codeseg
PUBLIC _arrayproc
include decout.asm
include macs.asm
_arrayproc proc near

push bp
mov bp,sp

mov di,[bp+4]
mov cx,[bp+6]
looptop:
        add word ptr [di],10
inc di
inc di
        loop looptop

pop bp
        ret
_arrayproc endp
end

Examples from current text. C++ part gets compiled in VC as console project and assembly parts get assembled by masm/ml.

For visual C:

Build an empty Win32 console project. Here is my test.cpp

extern "C" void clear();

/*extern "C" {

void clear();

}*/

int main() {

clear();

return 1;

}

Over in textpad, create an assembly module… Here is clear.asm

.586 ;Target processor. Use instructions for Pentium class machines

.MODEL FLAT, C ;Use the flat memory model. Use C calling conventions

.STACK ;Define a stack segment of 1KB (Not required for this example)

.DATA ;Create a near data segment. Local variables are declared after

;this directive (Not required for this example)

.CODE ;Indicates the start of a code segment.

clear PROC

xor eax, eax

xor ebx, ebx

ret

clear ENDP

END

If you can run ml (on your own computer) assemble (only) this file. Do not link because there is no entry point. Copy the obj file to your VC++ project

Here is my project:

I then ran it without debug – black screen opens. It doesn’t do anything.

Next example (from text) passing arguments to a function

C++ main:

#include <iostream>

using namespace std;

extern "C" int addem(int p1, int p2, int p3);

int main()

{ int total = addem( 10, 15, 25 );

cout << "Total = " << total << endl;

return 0;

}

Assembly subroutine

title The addem Subroutine (addem.asm)

; This subroutine links to Visual C++ 6.0.

.386P

.model flat

public _addem

.code

_addem proc near

push ebp

mov ebp,esp

mov eax,[ebp+16] ; first argument

add eax,[ebp+12] ; second argument

add eax,[ebp+8] ; third argument

pop ebp

ret

_addem endp

end

Encoding example: did not run this example

//header

void TranslateBuffer( char * buf, unsigned count,

unsigned char eChar );

//inline assembly module

#include "translat.h"

/* Translate a buffer of <count> bytes, using an encryption

character <eChar>. Uses an XOR operation (ASM function).*/

void TranslateBuffer( char * buf, unsigned count,

unsigned char eChar )

{

__asm {

mov esi,buf ; set index register

mov ecx,count /* set loop counter */

mov al,eChar

L1:

xor [esi],al

inc esi

Loop L1

} // asm

}

//c++

#include <iostream>

#include <fstream>

#include "translat.h"

using namespace std;

int main( int argcount, char * args[] )

{

// Read input and output files from the command line.

if( argcount < 3 ) {

cout << "Usage: encode infile outfile" << endl;

return -1;

}

const int BUFSIZE = 2000;

char buffer[BUFSIZE];

unsigned int count; // character count

unsigned char encryptCode;

cout << "Encryption code [0-255]? ";

cin >> encryptCode;

ifstream infile( args[1], ios::binary );

ofstream outfile( args[2], ios::binary );

cout << "Reading " << args[1] << " and creating "

<< args[2] << endl;

while (!infile.eof() )

{

infile.read(buffer, BUFSIZE );

count = infile.gcount();

TranslateBuffer(buffer, count, encryptCode);

outfile.write(buffer, count);

}

return 0;

}