Home »

How do I write code that reads data at memory location specified by segment and offset?

Question ListCategory: cHow do I write code that reads data at memory location specified by segment and offset?
jully882 author asked 2 years ago
1 Answers
ethanbrown author answered 1 year ago

Use peekb( ) function. This function returns byte(s) read from specific segment and offset
locations in memory. The following program illustrates use of this function. In this program

from VDU memory we have read characters and its attributes of the first row. The

information stored in file is then further read and displayed using peek( ) function.

#include <stdio.h>

#include <dos.h>

main( )

{

char far *scr = 0xB8000000 ;

FILE *fp ;

int offset ;

char ch ;

if ( ( fp = fopen ( "scr.dat", "wb" ) ) == NULL )

{

printf ( "nUnable to open file" ) ;

exit( ) ;

}

// reads and writes to file

for ( offset = 0 ; offset < 160 ; offset++ )

fprintf ( fp, "%c", peekb ( scr, offset ) ) ;

fclose ( fp ) ;

if ( ( fp = fopen ( "scr.dat", "rb" ) ) == NULL )

{

printf ( "nUnable to open file" ) ;

exit( ) ;

}

// reads and writes to file

for ( offset = 0 ; offset < 160 ; offset++ )

{

fscanf ( fp, "%c", &ch ) ;

printf ( "%c", ch ) ;

}

fclose ( fp ) ;

}

Please login or Register to Submit Answer