From: Luke Kenneth Casson Leighton Date: Wed, 2 Jan 2019 09:34:21 +0000 (+0000) Subject: add q table image X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=095eff7b470c055c5b3d0bb6726169ce5d7936c3;p=crowdsupply.git add q table image --- diff --git a/images/6600_q_table.png b/images/6600_q_table.png new file mode 100644 index 0000000..5372a8c Binary files /dev/null and b/images/6600_q_table.png differ diff --git a/updates/009_register_overwrites.mdwn b/updates/009_register_overwrites.mdwn index 396e4c0..e89e0c5 100644 --- a/updates/009_register_overwrites.mdwn +++ b/updates/009_register_overwrites.mdwn @@ -143,6 +143,12 @@ allow the prior Function Unit (the "overwritee") has just been destroyed. There is a simple solution to that: provide a *Queue* of Q-Table entries. +Below is what a 6600 Q-Table looks like (image courtesy of Mitch Alsup). +In the original 6600 it is a binary table with a unary decoder on the +left and a pair of unary encoders on the right. + +{{6600_q_table.png}} + Now we have exactly the information needed to "roll back", should an exception occur. Like many augmentations and enhancements to the 6600 Scoreboard system, it's kind-of obvious in retrospect. However the *real*