multiplication: result=32 bits , original numbers = 16 bit

[iseron]

Hi i need to obtain a 32 bit number for the size of an archive in FAT12-FAt16 root directory standard. (the standar said that the size always its a 32 bits number size in little endian form)

My purpose is to do an archive to fill all the space in a CompactFlash and i have to put the size in every case of CF size.

The variables:
unsigned long int sectors_cluster; // 16 bits?
unsigned long int fat_copies; // 16 bits?
unsigned long int sectores_por_fat; // 16 bits?


The function:
void directorio_raiz (int32 tamano) //tamano is "size" in spanish

The failed operation(return 16 bits instead of 32 bits):
directorio_raiz ((int32)512*lba_tot-512-(int32)512*fat_copies*sectores_por_fat-(int32)512*32);


What can i do?
I was thinking about to do an ATOI32( text) for reach my objective, but how to transform the "number" in "text"? same problem..

Ignacio.

[Ttelmah]

[iseron]

Let me explain better my problem.

1) the void function need a 32 bit entry, then write the size of this 32 bits onto the compact flash. But with the multiplication showed, i can't obtain the 32 bits value only a max of 65535 or 16 bits number FFFFh.
I have inside the void this "printf("\n\rtamaño grabado = %ld", tamano);" then i know the number introduced.

2) My way to write the operation, its because i think that the compiler "don't see" the parentesis of a big operation. My first test was directorio_raiz (512*(lba_tot-1-fat_copies*sectores_por_fat-32)); but returned a number like ~3000 or near to that. After change the way and puting all in a plain way i obtained a 16 bits. like a ~62000 .. don't remember.

Now i will use de "|" operator but in the manual appear like a bitwise inclusive or operator.

Other ideas for multipliying?

thanks.

[Ttelmah]

[PCM programmer]