Multiplying two ULONG values?

[Witchfinder]

Morning,

I have two ulong values blocks and LBA.

typedef struct _CAPACITY {
  ULONG LBA ;
  ULONG Blocks ;

} CAPACITY, *PCAPACITY;

And I can print them

printf("No of Logical block addresses        : %u  \n", wordSwap(receiveCapacity.LBA));
printf("length of blocks in bytes                : %u   \n", wordSwap(receiveCapacity.Blocks));

How does one multiply the values to get the total number of bytes on a disc? I've tried putting it into a few data types as I think the value "4,549,356,616" which is 4.23GB is too big for ULONG: Unsigned LONG. The range is 0 through 4294967295 decimal.

It has to be declared as ULONG from the MMC6 specs I'm working from.
wordswap reverses the byte order and it prints out fine.

ULONG Length_Bytes = wordSwap(recveiveCapacity.LBA) * wordSwap(recveiveCapacity.Blocks);
printf("\nLenth Bytes = %u", Length_Bytes);

= 254932992

I've tried using ulong64 and ulonglong.

Thanks!

[matsp]

You need to cast at least one of your input operands to a 64-bit value (same principle as if you wanted to use floating point multiply with two integer operands), and then print as 64-bit in the printf statement.

--
Mats

[Witchfinder]

 

ULONG64 Length_Bytes = (ULONG64) wordSwap(recveiveCapacity.LBA) * wordSwap(recveiveCapacity.Blocks);
printf("\nLenth Bytes = %u", Length_Bytes);

and

ULONG64 Length_Bytes = (ULONG64) wordSwap(recveiveCapacity.LBA) * (ULONG64) wordSwap(recveiveCapacity.Blocks);
printf("\nLenth Bytes = %u", Length_Bytes);

= 3623878656


It should be 8001767424. I think that's how you type cast anyway. The values print out correctly with the wordswap function. Ummm...

Thanks again.

[matsp]

and then print as 64-bit in the printf statement.

You missed that part.

In Windows, you'd use "%I64u".

--
Mats

[Witchfinder]

*Air 5.