//----------------------------------------------------------------
//	divtest.cpp
//
//	This program uses "inline assembly language" to test the
//	external software division routine named 'div_bl', based
//	on comparing all of its possible cases with results from
//	performing the same divisions in hardware.  Note that we
//	test here only those cases for which no "divide overlow"
//	can occur.  
//
//	compile using:  $ gcc divtest.cpp div_bl.o -o divtest
//
//	programmer: ALLAN CRUSE
//	written on: 12 OCT 2003
//----------------------------------------------------------------

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

extern void div_bl( void );	// function symbol

unsigned int	a, b, c, d;	// global variables

int main( void )
{
	printf( "\n---a--- --b--  hardware  software \n" );
	
	// iterate over all possible combinations 
	// of 16-bit dividend and 8-bit divisor 
	int	errors = 0;
	for (a = 0; a < 65536; a++)
		{
		for (b = 0; b < 256; b++)
			{
			printf( " a=%04X  b=%02X ", a, b );
			if ( ( a >> 8 ) < b )
				{	
				asm(" movw a, %ax ");
			       	asm(" movb b, %bl ");
				asm(" divb %bl ");
				asm(" movw %ax, d ");
				asm(" movw a, %ax ");
			       	asm(" movb b, %bl ");
				asm(" call div_bl ");
				asm(" movw %ax, c ");
				printf( "  c=%04X    d=%04X ", c, d );
				if ( c != d ) ++errors;
				if ( c == d ) printf( "     ok \n" );
				else	printf( "<--- error #%d \n", errors );
				}
			else	printf( "  (divide overflow)  \n" );
			}
		}
	
	printf( "\n\tNumber of errors = %d \n\n", errors );
}