From 43e60dab6a36b1781f0d939fc3bfd91acde87b84 Mon Sep 17 00:00:00 2001 From: Jacob Lifshay Date: Mon, 16 May 2022 19:28:39 -0700 Subject: [PATCH] fix urls --- openpower/sv/bitmanip.mdwn | 2 +- openpower/sv/bitmanip/grev_gorc_design.mdwn | 6 +++--- 2 files changed, 4 insertions(+), 4 deletions(-) diff --git a/openpower/sv/bitmanip.mdwn b/openpower/sv/bitmanip.mdwn index 2f208d36d..b6f53bb00 100644 --- a/openpower/sv/bitmanip.mdwn +++ b/openpower/sv/bitmanip.mdwn @@ -421,7 +421,7 @@ uint_xlen_t bmextrev(RA, RB, sh) # grevlut -([3x lower latency alternative](bitmanip/grev_gorc_design.mdwn)) +([3x lower latency alternative](grev_gorc_design/)) generalised reverse combined with a pair of LUT2s and allowing a constant `0b0101...0101` when RA=0, and an option to invert diff --git a/openpower/sv/bitmanip/grev_gorc_design.mdwn b/openpower/sv/bitmanip/grev_gorc_design.mdwn index 9d2a2f60a..879e7d268 100644 --- a/openpower/sv/bitmanip/grev_gorc_design.mdwn +++ b/openpower/sv/bitmanip/grev_gorc_design.mdwn @@ -2,17 +2,17 @@ The design is derived from a circuit for GRev made with muxes: -![grev_made_with_muxes.svg](grev_made_with_muxes.svg) +![grev_made_with_muxes.svg](../grev_made_with_muxes.svg) First, we convert that circuit to use And-Or-Invert gates, since that's an efficient way the muxes can be implemented: -![grev_made_with_aoi_gates.svg](grev_made_with_aoi_gates.svg) +![grev_made_with_aoi_gates.svg](../grev_made_with_aoi_gates.svg) Notice how each And-Or-Invert has both a bit of `SH` and `~SH` as inputs? Those can be converted to separate inputs, controlled by the bits of `SH` using the instruction's immediate as a pair of 2-bit look-up-tables. This requires 4-bits of immediate. This gives us our final design: -![grev_gorc_combination.svg](grev_gorc_combination.svg) +![grev_gorc_combination.svg](../grev_gorc_combination.svg) Notice how this still has an overall circuit latency that is essentially equivalent to grev's latency (or shift/rotate's latency). Also notice how this circuit allows specifying much more than just `grev` or `gorc` instructions. A final layer of XOR gates can be added at the input and output, allowing it to function as a `gandc` instruction too, requiring a total of 6-bits of immediate. -- 2.30.2