HW5: Shifter overkill question

[Jeremy Cowles]

I implemented the full 16 bit shamt shifter because I missed the line in the
spec that tells you to ignore bits > 4 in shamt. Is it ok to leave it like
this, or should I remove the additional logic so it ignores the bits greater
than the first 4?

Thanks,
Jeremy

[[Instr] Albert Chae]

It probably won't matter so much... What's the behavior if you shift
using more than 4 bits? Does everything 0 out?

Albert

Post by Jeremy Cowles
I implemented the full 16 bit shamt shifter because I missed the line in the
spec that tells you to ignore bits > 4 in shamt. Is it ok to leave it like
this, or should I remove the additional logic so it ignores the bits greater
than the first 4?
Thanks,
Jeremy

[Jeremy Cowles]

Yea, after shifting more than 15 bits, it all goes to zeros or 1's depending
on the operation.

Post by [Instr] Albert Chae
It probably won't matter so much... What's the behavior if you shift
using more than 4 bits? Does everything 0 out?
Albert

Post by Jeremy Cowles
I implemented the full 16 bit shamt shifter because I missed the line in
the spec that tells you to ignore bits > 4 in shamt. Is it ok to leave it
like this, or should I remove the additional logic so it ignores the bits
greater than the first 4?
Thanks,
Jeremy

[[Instr] Albert Chae]

We won't test inputs greater than 4 bits on the shifter, so this is fine.

Albert

Post by Jeremy Cowles
Yea, after shifting more than 15 bits, it all goes to zeros or 1's depending
on the operation.

Post by [Instr] Albert Chae
It probably won't matter so much... What's the behavior if you shift
using more than 4 bits? Does everything 0 out?
Albert

Post by Jeremy Cowles
I implemented the full 16 bit shamt shifter because I missed the line in
the spec that tells you to ignore bits > 4 in shamt. Is it ok to leave it
like this, or should I remove the additional logic so it ignores the bits
greater than the first 4?
Thanks,
Jeremy

[[Instr] Albert Chae]

Why would we care about having the shamt be negative when we can just
select the direction of the shift? Nobody wants to think about shifting
-5 bits left; that's too confusing.

Albert

P.S. Don't forget what we talked about today.

I was going to ask if shamt could be a negative value, but I guess the answer
is no, unless we go 8 one way and 8 the other. Since I probably shouldn't
have posted this, but as ever, I have OCD on fact checking, I will add the
thought that maybe this has something to do with the way the barrel shifter
works. OOps. nobody is supposed to pay attention to what a barrel shifter
http://inst.eecs.berkeley.edu/~cs150/fa05/HWs/HW10sol.doc

Post by Jeremy Cowles
I implemented the full 16 bit shamt shifter because I missed the line in the
spec that tells you to ignore bits > 4 in shamt. Is it ok to leave it like
this, or should I remove the additional logic so it ignores the bits greater
than the first 4?
Thanks,
Jeremy