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Code: Select all

void md(){
int i,s,x;
char tmp_name[9]={' '};
gets(tmp_name,9);
char *name,*fat={' '};
 
name=toupper(tmp_name);
printf("\n");
for(i=0;i<8;i++) 
putch(name[i]);
 

//load fat into memory
for(s=0,i=1;i<10;i++,s+=512)
 {
  floppy_read(i);
  for(x=0;x<512;x++)
   fat[x+s]=floppy_dmabuf[x];
 }

 /*
  find first entry
  in the root directory */
 
int j=get_first_entry();

 //get first free cluster;
int cluster=32;
while(read_fat(fat,cluster)!=0)
 {
   cluster++ ;
 }
 
int attr=j+11;

 //start cluster
int st=j+26;
int size=j+28;

 //load cluster 19
 //into floppy_dmabuf
floppy_read(19);

 //set the dir name
for(i=0;i<8;i++,j++)
  floppy_dmabuf[j]=name[i];

 //set dir attribute
floppy_dmabuf[attr] = read_only | directory ;

floppy_dmabuf[st]=cluster;
floppy_dmabuf[size]=0;
 
 //write data to 
 //root directory
floppy_write(19);

 //set fat
write_fat(cluster,fat,0xFFF);
 
 //write new fat 
 //to floppy
for(s=0,i=1;i<10;i++,s+=512)
 {
  for(x=0;x<512;x++)
   floppy_dmabuf[x]=fat[x+s];
  floppy_write(i);
 }
}

Code: Select all

int read_fat(char *fat,int entry)
{
 int offset = (entry * 3) / 2;
 if (entry & 1)
  return((int)((short)fat[offset + 1] << 4)|(((short)fat[offset] & 0x00f0) >> 4));
 else
  return((int)(((short)fat[offset + 1] & 0x000f) << 8)|(short)fat[offset]);

}

void write_fat(int cluster,char *fat,unsigned value)
{
 unsigned index;
 index=(unsigned)(cluster * 1.5);
 if(cluster % 2)
  {
   value =value << 4;
   fat[index + 1]=(unsigned char)((value & 0xFF00)>>8);
   fat[index]=(unsigned char)(fat[index] & 0x0F)+(unsigned char)((value & 0xF0));
  }
 else
  {
   fat[index+1]=(unsigned char)(fat[index+1] & 0xf0)+(unsigned char)((value &0x0f00)>>8);
   fat[index]=(unsigned char)(value &0x00ff);
  }
}

Code: Select all

void storecluster(WORD value,int cluster)
{
	//store the value at the cluster in the fat
	int temp;
	WORD oldcluster;	//what was previously stored in that cluster
	oldcluster=_farpeekw(fatas,(cluster>>1)+cluster);
	if((cluster & 1)==1)
	{
		oldcluster=oldcluster<<12;
		oldcluster=oldcluster>>12;
		temp=oldcluster+(value<<4);
	}
	else
	{
		temp=oldcluster>>12;
		temp=temp<<12;
		temp=temp+value;
	}
	_farpokew(fatas,(cluster>>1)+cluster,(WORD)temp);
}