From b4057eada8e7a0cd34f9cc8bf4fa14ea73b82cc5 Mon Sep 17 00:00:00 2001 From: lkcl Date: Wed, 6 Dec 2023 15:13:25 +0000 Subject: [PATCH] --- openpower/sv/cookbook/pospopcnt.mdwn | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/openpower/sv/cookbook/pospopcnt.mdwn b/openpower/sv/cookbook/pospopcnt.mdwn index bfedde880..516db6d2c 100644 --- a/openpower/sv/cookbook/pospopcnt.mdwn +++ b/openpower/sv/cookbook/pospopcnt.mdwn @@ -69,11 +69,6 @@ bit-position, of an array of input values. Refer to Fig.2 alt="pospopcnt" width="60%" /> - - -
- - # Visual representation of the pospopcount algorithm In order to perform positional popcount we need to go through series of steps shown below in figures 3, 4, 5 & 6. @@ -107,12 +102,17 @@ Fig.6 depicts how each of the intermediate results are accumulated. It is worth noting that each intermediate result is independent of the other intermediate results and also parallel reduction can be applied to all of them -individually. This gives two opportunities for parallelism. +individually. This gives *two* opportunities for +hardware parallelism rather than one. pospopcnt - +In short this algorithm is very straightforward to implement thanks to the two +crucial instructions, `gbbd` and `popcntd`. Below is a walkthrough of the +assembler, keeping it very simple, and exploiting only one of the opportunities +for parallelism (by not including the Parallel Reduction opportunity mentioned +above). # Walkthrough of the assembler -- 2.30.2