From: Luke Kenneth Casson Leighton <lkcl@lkcl.net>
Date: Mon, 20 May 2019 04:02:46 +0000 (+0100)
Subject: add 6600 page
X-Git-Tag: convert-csv-opcode-to-binary~4681
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=e19a5012352bcbd5d242efe65d0b6d03b2a00b2e;p=libreriscv.git

add 6600 page
---

diff --git a/3d_gpu/6600scoreboard.mdwn b/3d_gpu/6600scoreboard.mdwn
index 96523f33f..9c859d8ba 100644
--- a/3d_gpu/6600scoreboard.mdwn
+++ b/3d_gpu/6600scoreboard.mdwn
@@ -13,7 +13,12 @@ However the same thing has to be done for the read path, as well.
 
 Below are the modifications required to add a read-release path that
 will prevent a Function Unit from requesting a GoRead signal when it
-has no need to read registers.
+has no need to read registers.  Note that once both the Busy and GoRead
+signals combined are dropped, the ReadRelease is dropped.
+
+Note that this is a loop: GoRead (ANDed with Busy) goes through
+to the priority picker, which generates GoRead, so it is critical
+(in a modern design) to use a clock-sync'd latch in this path.
 
 [[!img comp_unit_req_rel.jpg]]
 [[!img group_pick_rd_rel.jpg]]