3 ms·

As this is the number 1 story on HN now: can someone explain what kind of improvements we will see in day to day use from this?

ams6110 12y ago
From the story.... 1. Image conversion (RGB structure to some other) 2. N-dimentional coordinates. (Normalize array of XYZ points) 3. Multiplication of vectors by constant matrix
azraai 12y ago
Faster multi dimensional loops. Quicker raw image compression. That are few things that came across my mind.
_wmd 12y ago
The article mentions two: unpacking 24 bit values and matrix multiplication, both might be something you'd find in a software video (de)compressor or a computer game
- vinkelhake 12y ago
  Where did you get 24 from? It's about vectorizing loads of 3 elements. The elements don't have to be 8-bit. The second example uses floats.
  - cwp 12y ago
    Yeah, but 24-bit values (RBG) are what you'd find in video and gaming applications.
    - vardump 12y ago
      Games, at least what I've seen, usually just don't use 3x(8|16|32) bits per pixel, if it's not needed as alpha. It's pretty rare to pack 24/48/96-bit pixels in memory. Traditionally, unaligned loads are just not worth it. Sometimes packed formats were worth it. I remember doing RLE schemes for fast "alpha blending" (anti-aliased blitting really!) back in 2000 or so, before MMX or GPUs were common. The scheme I used had three different types of run lengths. Completely transparent, pre-multiplied alpha blended and completely opaque. 16-bit pre-multiplied values were in memory in 32-bit format like this: URGBU00A. Groups of 5 bits, except U denotes unused single bit. Frame buffer in RAM was in 15 bit format, 0RRRRRGGGGGBBBBB. With this scheme, alpha-blending needed totally just one multiply per pixel [1], compared to three with usual pre-multiplied alpha or six with normal alpha without pre-multiplication. [1]: Frame buffer pixels were masked and shifted into 000000GGGGG000000RRRRR00000BBBBB, multiplied by A and shifted back in place. Because all values were 5 bit entities, no overflow (overlap) could occur in multiply, thus one multiply yielded 3 multiplied frame buffer pixel values, for R, G and B!
    - kayamon 12y ago
      Presumably loading a 3D vector would be a good use-case?

ams6110 12y ago

From the story.... 1. Image conversion (RGB structure to some other) 2. N-dimentional coordinates. (Normalize array of XYZ points) 3. Multiplication of vectors by constant matrix

azraai 12y ago

Faster multi dimensional loops. Quicker raw image compression. That are few things that came across my mind.

_wmd 12y ago

The article mentions two: unpacking 24 bit values and matrix multiplication, both might be something you'd find in a software video (de)compressor or a computer game

vinkelhake 12y ago
Where did you get 24 from? It's about vectorizing loads of 3 elements. The elements don't have to be 8-bit. The second example uses floats.
- cwp 12y ago
  Yeah, but 24-bit values (RBG) are what you'd find in video and gaming applications.
  - vardump 12y ago
    Games, at least what I've seen, usually just don't use 3x(8|16|32) bits per pixel, if it's not needed as alpha. It's pretty rare to pack 24/48/96-bit pixels in memory. Traditionally, unaligned loads are just not worth it. Sometimes packed formats were worth it. I remember doing RLE schemes for fast "alpha blending" (anti-aliased blitting really!) back in 2000 or so, before MMX or GPUs were common. The scheme I used had three different types of run lengths. Completely transparent, pre-multiplied alpha blended and completely opaque. 16-bit pre-multiplied values were in memory in 32-bit format like this: URGBU00A. Groups of 5 bits, except U denotes unused single bit. Frame buffer in RAM was in 15 bit format, 0RRRRRGGGGGBBBBB. With this scheme, alpha-blending needed totally just one multiply per pixel [1], compared to three with usual pre-multiplied alpha or six with normal alpha without pre-multiplication. [1]: Frame buffer pixels were masked and shifted into 000000GGGGG000000RRRRR00000BBBBB, multiplied by A and shifted back in place. Because all values were 5 bit entities, no overflow (overlap) could occur in multiply, thus one multiply yielded 3 multiplied frame buffer pixel values, for R, G and B!
  - kayamon 12y ago
    Presumably loading a 3D vector would be a good use-case?