Messages in this thread | | | Date | Fri, 22 Jan 1999 00:53:59 -0600 | From | "Thomas E. Dodd /CSDC" <> | Subject | Re: Structure vs purism ? |
| |
Stefan Monnier wrote: > I think a lot of the goto's could be removed as soon as there is a decent > possibility to tell the compiler to optimize for a certain case. This was > discussed on the egcs lists some time ago IIRC. > > > compare against a final value because on most/many/(all?) processors > > the flags change automatically when decrementing to zero or decrementing > > to a negative number. > > MIPS and Alpha don't have `flags'. But I still agree that it's most of the > time cheaper to check against 0 than against any other value.
Then how do you get a beq or bne instruction? There must be a status register that knows if the last operation resulted in 0.
The architecture coure I too was based on the MIPS. We had a 0 bit from the ALU that could be checked.
-Thomas
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/
| |