Short Vectors Versus Long Vectors

Liste des GroupesRevenir à c arch 
Sujet : Short Vectors Versus Long Vectors
De : ldo (at) *nospam* nz.invalid (Lawrence D'Oliveiro)
Groupes : comp.arch
Date : 23. Apr 2024, 02:29:32
Autres entêtes
Organisation : A noiseless patient Spider
Message-ID : <v06vdb$17r2v$1@dont-email.me>
User-Agent : Pan/0.155 (Kherson; fc5a80b8)
Adding the typical kind of vector-processing instructions to an
instruction set inevitably leads to a combinatorial explosion in the
number of opcodes. This kind of thing makes a mockery of the “R” in
“RISC”.

Interesting to see that the RISC-V folks are staying off this path;
instead, they are reviving an old idea from Seymour Cray’s original
machines that bear his name: a vector pipeline. Instead of being limited
to processing 4 or 8 operands at a time, the Cray machines could operate
(sequentially, but rapidly) on variable-length vectors of up to 64
elements with a single setup sequence. RISC-V seems to make the limit on
vector length an implementation choice, with a value of 32 being mentioned
in the spec.

The way it avoids having separate instructions for each combination of
operand types is to have operand-type registers as part of the vector
unit. This way, only a small number of instructions is required to set up
all the combinations of operand/result types. You then give it a kick in
the guts and off it goes.

Detailed spec here:
<https://github.com/riscv/riscv-v-spec/blob/master/v-spec.adoc>.

Date Sujet#  Auteur
23 Apr 24 * Short Vectors Versus Long Vectors109Lawrence D'Oliveiro
23 Apr 24 +* Re: Short Vectors Versus Long Vectors97MitchAlsup1
23 Apr 24 i+* Re: Short Vectors Versus Long Vectors21Lawrence D'Oliveiro
23 Apr 24 ii+* Re: Short Vectors Versus Long Vectors15Anton Ertl
23 Apr 24 iii+* Re: Short Vectors Versus Long Vectors3Lawrence D'Oliveiro
23 Apr 24 iiii+- Re: Short Vectors Versus Long Vectors1Anton Ertl
23 Apr 24 iiii`- Re: Short Vectors Versus Long Vectors1MitchAlsup1
23 Apr 24 iii+- Re: Short Vectors Versus Long Vectors1MitchAlsup1
23 Apr 24 iii`* Re: Short Vectors Versus Long Vectors10BGB
24 Apr 24 iii `* Re: Short Vectors Versus Long Vectors9MitchAlsup1
24 Apr 24 iii  `* Re: Short Vectors Versus Long Vectors8BGB
24 Apr 24 iii   +* Re: Short Vectors Versus Long Vectors6Lawrence D'Oliveiro
24 Apr 24 iii   i`* Re: Short Vectors Versus Long Vectors5MitchAlsup1
24 Apr 24 iii   i +* Re: Short Vectors Versus Long Vectors2BGB
24 Apr 24 iii   i i`- Re: Short Vectors Versus Long Vectors1Lawrence D'Oliveiro
24 Apr 24 iii   i `* Re: Short Vectors Versus Long Vectors2Terje Mathisen
25 Apr 24 iii   i  `- Re: Short Vectors Versus Long Vectors1MitchAlsup1
24 Apr 24 iii   `- Re: Short Vectors Versus Long Vectors1MitchAlsup1
23 Apr 24 ii`* Re: Short Vectors Versus Long Vectors5MitchAlsup1
23 Apr 24 ii `* Re: Short Vectors Versus Long Vectors4Lawrence D'Oliveiro
24 Apr 24 ii  `* Re: Short Vectors Versus Long Vectors3MitchAlsup1
24 Apr 24 ii   `* Re: Short Vectors Versus Long Vectors2Lawrence D'Oliveiro
24 Apr 24 ii    `- Re: Short Vectors Versus Long Vectors1MitchAlsup1
24 Apr 24 i`* Re: Short Vectors Versus Long Vectors75John Savard
24 Apr 24 i +* Re: Short Vectors Versus Long Vectors26MitchAlsup1
24 Apr 24 i i+* Re: Short Vectors Versus Long Vectors23John Savard
24 Apr 24 i ii+* Re: Short Vectors Versus Long Vectors2Lawrence D'Oliveiro
24 Apr 24 i iii`- Re: Short Vectors Versus Long Vectors1BGB
24 Apr 24 i ii+* Re: Short Vectors Versus Long Vectors19Anton Ertl
25 Apr 24 i iii`* Re: Short Vectors Versus Long Vectors18Lawrence D'Oliveiro
25 Apr 24 i iii +* Re: Short Vectors Versus Long Vectors2Michael S
27 Apr 24 i iii i`- Re: Short Vectors Versus Long Vectors1Lawrence D'Oliveiro
25 Apr 24 i iii `* Re: Short Vectors Versus Long Vectors15John Levine
25 Apr 24 i iii  `* Re: Short Vectors Versus Long Vectors14MitchAlsup1
25 Apr 24 i iii   +* Re: Short Vectors Versus Long Vectors9Michael S
25 Apr 24 i iii   i`* Re: Short Vectors Versus Long Vectors8MitchAlsup1
25 Apr 24 i iii   i `* Re: Short Vectors Versus Long Vectors7Michael S
25 Apr 24 i iii   i  `* Re: Short Vectors Versus Long Vectors6BGB
27 Apr 24 i iii   i   `* Re: Short Vectors Versus Long Vectors5Thomas Koenig
27 Apr 24 i iii   i    +* Re: Short Vectors Versus Long Vectors3John Levine
28 Apr 24 i iii   i    i`* Re: Short Vectors Versus Long Vectors2Lawrence D'Oliveiro
28 Apr 24 i iii   i    i `- Re: Short Vectors Versus Long Vectors1John Levine
28 Apr 24 i iii   i    `- Re: Short Vectors Versus Long Vectors1Tim Rentsch
26 Apr 24 i iii   `* Re: Short Vectors Versus Long Vectors4Lawrence D'Oliveiro
26 Apr 24 i iii    `* Re: Short Vectors Versus Long Vectors3MitchAlsup1
26 Apr 24 i iii     `* Re: Short Vectors Versus Long Vectors2Lawrence D'Oliveiro
26 Apr 24 i iii      `- Re: Short Vectors Versus Long Vectors1MitchAlsup1
24 Apr 24 i ii`- Re: Short Vectors Versus Long Vectors1David Schultz
27 Apr 24 i i`* Re: Short Vectors Versus Long Vectors2aph
27 Apr 24 i i `- Re: Short Vectors Versus Long Vectors1MitchAlsup1
24 Apr 24 i +* Re: Short Vectors Versus Long Vectors2Lawrence D'Oliveiro
24 Apr 24 i i`- Re: Short Vectors Versus Long Vectors1Anton Ertl
24 Apr 24 i +- Re: Short Vectors Versus Long Vectors1Thomas Koenig
24 Apr 24 i `* Re: Short Vectors Versus Long Vectors45Anton Ertl
24 Apr 24 i  +* Re: Short Vectors Versus Long Vectors43Lawrence D'Oliveiro
24 Apr 24 i  i`* Re: Short Vectors Versus Long Vectors42Anton Ertl
25 Apr 24 i  i `* Re: Short Vectors Versus Long Vectors41Lawrence D'Oliveiro
25 Apr 24 i  i  `* Re: Short Vectors Versus Long Vectors40John Savard
25 Apr 24 i  i   `* Re: Short Vectors Versus Long Vectors39Lawrence D'Oliveiro
25 Apr 24 i  i    +* Re: Short Vectors Versus Long Vectors3Michael S
26 Apr 24 i  i    i`* Re: Short Vectors Versus Long Vectors2Lawrence D'Oliveiro
26 Apr 24 i  i    i `- Re: Short Vectors Versus Long Vectors1Michael S
25 Apr 24 i  i    +* Re: Short Vectors Versus Long Vectors7John Levine
25 Apr 24 i  i    i`* Re: Short Vectors Versus Long Vectors6Thomas Koenig
29 Apr 24 i  i    i `* Re: Short Vectors Versus Long Vectors5George Neuner
29 Apr 24 i  i    i  +* Re: Short Vectors Versus Long Vectors3Terje Mathisen
29 Apr 24 i  i    i  i+- Re: Short Vectors Versus Long Vectors1BGB
30 Apr 24 i  i    i  i`- Re: Short Vectors Versus Long Vectors1George Neuner
29 Apr 24 i  i    i  `- Re: lotsa power, Short Vectors Versus Long Vectors1John Levine
25 Apr 24 i  i    `* Re: Short Vectors Versus Long Vectors28John Savard
25 Apr 24 i  i     `* Re: Short Vectors Versus Long Vectors27Thomas Koenig
25 Apr 24 i  i      +* Re: lots of juice, Short Vectors Versus Long Vectors3John Levine
27 Apr 24 i  i      i`* Re: lots of juice, Short Vectors Versus Long Vectors2Thomas Koenig
28 Apr 24 i  i      i `- Re: lots of juice, Short Vectors Versus Long Vectors1Lawrence D'Oliveiro
28 Apr 24 i  i      `* Re: Short Vectors Versus Long Vectors23Tim Rentsch
30 Apr 24 i  i       `* Re: Short Vectors Versus Long Vectors22Thomas Koenig
30 Apr 24 i  i        +* Re: old power, Short Vectors Versus Long Vectors19John Levine
30 Apr 24 i  i        i`* Re: old power, Short Vectors Versus Long Vectors18Lawrence D'Oliveiro
1 May 24 i  i        i `* Re: old power, Short Vectors Versus Long Vectors17John Levine
1 May 24 i  i        i  +- Re: old power, Short Vectors Versus Long Vectors1MitchAlsup1
2 May 24 i  i        i  `* Re: old power, Short Vectors Versus Long Vectors15BGB
2 May 24 i  i        i   `* Re: old power, Short Vectors Versus Long Vectors14MitchAlsup1
3 May 24 i  i        i    +- Re: old power, Short Vectors Versus Long Vectors1BGB
3 May 24 i  i        i    `* Re: old power, Short Vectors Versus Long Vectors12Lawrence D'Oliveiro
3 May 24 i  i        i     `* Re: old power, Short Vectors Versus Long Vectors11BGB
4 May 24 i  i        i      `* Re: old power, Short Vectors Versus Long Vectors10MitchAlsup1
5 May 24 i  i        i       +* Re: old power, Short Vectors Versus Long Vectors4Thomas Koenig
5 May 24 i  i        i       i+- Re: old power, Short Vectors Versus Long Vectors1BGB
5 May 24 i  i        i       i`* Re: old power, Short Vectors Versus Long Vectors2MitchAlsup1
5 May 24 i  i        i       i `- Re: old power, Short Vectors Versus Long Vectors1BGB
5 May 24 i  i        i       +* Re: old power, Short Vectors Versus Long Vectors2BGB
5 May 24 i  i        i       i`- Re: old power, Short Vectors Versus Long Vectors1MitchAlsup1
6 May 24 i  i        i       `* Re: not even sort of old power, Short Vectors Versus Long Vectors3John Levine
6 May 24 i  i        i        +- Re: not even sort of old power, Short Vectors Versus Long Vectors1MitchAlsup1
6 May 24 i  i        i        `- Re: not even sort of old power, Short Vectors Versus Long Vectors1Thomas Koenig
1 May 24 i  i        `* Re: Short Vectors Versus Long Vectors2Tim Rentsch
1 May 24 i  i         `- Re: Short Vectors Versus Long Vectors1Thomas Koenig
24 Apr 24 i  `- Re: Short Vectors Versus Long Vectors1MitchAlsup1
30 Apr 24 `* Re: Short Vectors Versus Long Vectors11MitchAlsup1
30 Apr 24  +- Re: Short Vectors Versus Long Vectors1MitchAlsup1
1 May 24  `* Re: Short Vectors Versus Long Vectors9Lawrence D'Oliveiro

Haut de la page

Les messages affichés proviennent d'usenet.

NewsPortal