Add example for vec_bperm #48

vec_bperm is a challenge for showing an example using just tables,
but I've made an attempt.

Three tables are used:

The values of the input vectors a and b.
A zoomed in view of the last two bytes of a and the bit
manipulations therein that leads to the intermediate result.
The result vector r.

Only one example has been provided, but it's getting big.

Fixes #14.

PDF:
web:

Signed-off-by: Paul A. Clarke pc@us.ibm.com

vec_bperm is a challenge for showing an example using just tables, but I've made an attempt. Three tables are used: - The values of the input vectors *a* and *b*. - A zoomed in view of the last two bytes of *a* and the bit manipulations therein that leads to the intermediate result. - The result vector *r*. Only one example has been provided, but it's getting big. Fixes #14. * PDF: ![Screenshot from 2020-05-07 20-30-24](https://user-images.githubusercontent.com/12301795/81360556-d1aafd80-90a1-11ea-8a17-21d76c2fbe86.png) * web: ![Screenshot from 2020-05-07 20-29-58](https://user-images.githubusercontent.com/12301795/81360564-d96aa200-90a1-11ea-9879-45eb6ee7e1ef.png) Signed-off-by: Paul A. Clarke <pc@us.ibm.com>

This is correct, except for one piece of confusion.

The part that says "bit indices b[i] (0 <= i < 16), ([70..7F])" makes it seem like b is a little-endian vector, as those numbers appear from right-to-left, not left-to-right. I would prefer that you write (7F, 7E, ..., 70) for clarity. Otherwise looks good with that change.

Thanks!

This is correct, except for one piece of confusion. The part that says "bit indices b[i] (0 <= i < 16), ([70..7F])" makes it seem like b is a little-endian vector, as those numbers appear from right-to-left, not left-to-right. I would prefer that you write (7F, 7E, ..., 70) for clarity. Otherwise looks good with that change. Thanks!

Labels Milestones

Add example for vec_bperm #48

Step 1:

Step 2: