From a9a3b8f7ab7f2067843a9a642447a9b7270440ce Mon Sep 17 00:00:00 2001
From: Julian Blake Kongslie
Date: Sun, 21 Nov 2021 13:28:55 -0800
Subject: Implement switches Start and LoadAdd.

---
 PLAN | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

(limited to 'PLAN')

diff --git a/PLAN b/PLAN
index bdf6256..562c8ab 100644
--- a/PLAN
+++ b/PLAN
@@ -1,15 +1,15 @@
 Turn on blinkenlights from the PDP core
 
 Implement switch features:
-    Start
-    Load_Add
-    Deposit
-    Examine
-    The DF* IF* and SR* data switches
+    Deposit - needs a state machine
+        [pc++] = switch_sr
+    Examine - needs a state machine
+        led_memdata = [pc++]
 
 Don't ignore 6000 and 6001
 
 Add "interrupts enabled" flag
+    switch_start clears this
 6000, 6001, 6002 should properly handle it
     6000 - skip next instruction if interrupts are enabled; disable interrupts (we should probably do this immediately)
     6001 - enable interrupts (after next instruction)
@@ -26,3 +26,9 @@ Sources of interrupts observed:
     TTO ready for output interrupt - this looks like a very likely candidate
     TTI input ready interrupt - this looks like a very likely candidate
         Looks like these happen even when there is no input available - might be caused by the program itself doing something a little funny
+
+Implement IF/DF fields
+    Will need to update behaviour of switch_load_add
+
+Add a macro for reversing polarity of switch_sing_step and switch_sing_inst and
+making switch_dep happen on key lift instead of key press
-- 
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