Re: linux-next: triage for March 18, 2012

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Valdis.Kletnieks@xxxxxx wrote:

> Umm.. it's not clear to *me* that it's intended to be a negative 16 bit?  Or
> am I just missing context not present in the patch?
> 
> (I have no idea if the rest of the patch is OK or not, but that comment
> didn't give me warm fuzzies....)

Sorry, I haven't explained it well.

The patch permits a 64-bit hosted assembler to represent a large 32-bit
unsigned integer (such as 0xfffffff1) as a negative integer where the
instruction being assembled has a signed immediate operand.

For instance, the ANDI instruction on FRV takes a small signed integer (10
bits IIRC) that it sign-extends to 32-bits before using - so to clear a single
low-order bit, I pass in, say, ~0x2 and the assembler represents this as a
negative value.

The problem was that in a 64-bit hosted assembler, the unsigned 32-bit integer
gets converted to an unsigned 64-bit integer - which doesn't then appear
negative (whereas in a 32-bit hosted assembler it does).

David
--
To unsubscribe from this list: send the line "unsubscribe linux-next" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html


[Index of Archives]     [Linux Kernel]     [Linux USB Development]     [Yosemite News]     [Linux SCSI]

  Powered by Linux