//-------------------------------------------------------------------
//	seestack.cpp
//
//	This program displays a hexadecimal and ascii dump of the
//	application's stack as it existed upon entry to 'main()',
//	and it illustrates the use of "inline" assembly language.
//
//	(A student's question prompted the writing of this demo.)
//
//	Suggestion: try executing this program with some command-
//	line arguments, and see where they show up in the output:
//
//		Example:  $ ./seestack xx yyyy zzzz
//
//	programmer: ALLAN CRUSE
//	written on: 07 OCT 2003
//	revised on: 15 MAR 2003 -- to show ESP, EBP, and envp values
//-------------------------------------------------------------------

#include <stdio.h>	// for printf() 

#define KERNEL_BASE_ADDRESS 0xC0000000

unsigned long tos, ebp, len;
unsigned char *where = (unsigned char *)KERNEL_BASE_ADDRESS;	
unsigned char ch;
int	i, j;


int main( int argc, char **argv, char **envp )
{
	// insert statement that copies %esp-value to a variable
	asm(" movl %esp, tos ");
	asm(" movl %ebp, ebp ");

	// calculate the size of the active stack area (in bytes)
	len = KERNEL_BASE_ADDRESS - tos;	

	// loop to display the contents of the active stack area
	for (i = 0; i < len; i += 16)
		{
		where -= 16;
		printf( "\n%08X: ", where );
		for (j = 0; j < 16; j++) printf( "%02X ", where[j] );
		for (j = 0; j < 16; j++)
			{
			ch = where[ j ];
			if (( ch < 0x20 )||( ch > 0x7E )) ch = '.';
			printf( "%c", ch );
			}
		}
	printf( "\n" );
	printf( "\n  ebp=%08X  ", ebp );	
	printf( "\n  esp=%08X  ", tos );	
	printf( "\n&argc=%08X  argc=%08X ", &argc, argc );
	printf( "\n&argv=%08X  argv=%08X ", &argv, argv );
	printf( "\n&envp=%08X  envp=%08X ", &envp, envp );
	printf( "\n\n" );
}