A question to IT KBers, part III

[enigma51]

Whatever works for you bro.

You cant tell me you believe that your question is going to establish if someone can do the job or not?

[jrandom]

You cant tell me you believe that your question is going to establish if someone can do the job or not?

I can tell you that I'm not going to have this argument with you on the forum.

[enigma51]

I can tell you that I'm not going to have this argument with you on the forum.

who's having a argument?

[jrandom]

who's having a argument?

If you say my question won't establish whether someone can do the job, and I say you're wrong about that, then we're having an argument.

[Street Gerbil]

Ok, here is another one:
I get more or less what the code does (although I am still amazed that this code would even compile) but what really gets to me is the second part of the question: "Why would someone want to do something like that?"
(Taken from Stroustrup's exercises)

void send (int * to , int * from , int count )
// Duff’s device. Helpful comment deliberately deleted.
{
	int n = (count +7 )/8 ;
	switch (count %8 ) 
	{
		case 0 : 
			do { *to++ = *from++;
		case 7 : *to++ = *from++;
		case 6 : *to++ = *from++;
		case 5 : *to++ = *from++;
		case 4 : *to++ = *from++;
		case 3 : *to++ = *from++;
		case 2 : *to++ = *from++;
		case 1 : *to++ = *from++;
				}while (--n>0) ;
	}
}

[imdying]

I can't remember if you were looking for work in Christchurch or not, but if so, pm and I will refer you to a recruiter that has worked for myself and others in the past.

[jrandom]

"Why would someone want to do something like that?"

Loop unrolling to optimise memory-to-memory copies in embedded systems.

Edit: I'd suspect that most modern compilers would be capable of achieving the same performance out of more conventionally-written code.

[enigma51]

Loop unrolling to optimise memory-to-memory copies in embedded systems.

Edit: I'd suspect that most modern compilers would be capable of achieving the same performance out of more conventionally-written code.

Dont you think that simply asking the question how you optimize memory to memory copies do the trick?

1 It gives the person an idea of what he/she can expect from the role. IE clearly you are having memory issues
2. You dont look like a prick trying to being smart

[hdus001]

Heres one that I was asked:

You have a processor that only has one register and only supports one instruction - "DCX LABEL" - which means decrement the value in the register and jump to LABEL if new value in register is not 0. Write a loop that'll decrements any number in the register (positive or negative) to 0.

[jrandom]

Dont you think that simply asking the question how you optimize memory to memory copies do the trick?

Of course. I personally would never dump Duff's Device in front of someone and say "what's that good for then".

Edit:

You dont look like a prick trying to being smart

You have some emotional issues about 'smart' people, don't you? Give it a rest, man, just relax about the whole subject.

[Street Gerbil]

Heres one that I was asked:

You have a processor that only has one register and only supports one instruction - "DCX LABEL" - which means decrement the value in the register and jump to LABEL if new value in register is not 0. Write a loop that'll decrements any number in the register (positive or negative) to 0.

Ok, here is the opinion that would have gotten me thrown out of your interview:
you write the following line:

label1: dcx label1

If register value is positive, it will iterate until it becomes zero.
If it is zero it will exit right away.
If it is negative, it will happily decrement until the underflow, at which stage the value in the register will become positive and will keep decrementing itself to zero.
What's the right answer?

[enigma51]

Of course. I personally would never dump Duff's Device in front of someone and say "what's that good for then".

Edit:



You have some emotional issues about 'smart' people, don't you? Give it a rest, man, just relax about the whole subject.

If you refering to yourself as being smart you are sadly mistaken.
I find you arrogant and a know it all.

[jrandom]

I find you arrogant and a know it all.

Gah. I just can't win, can I?

Oh, well. The line to join the club starts over there ---------->

[nodrog:Me]

can somebody explain how to set the clock on my microwave?

[Ixion]

That's hardware. This is a software discussion