Added info about the monitor.

1 files changed, 45 insertions, 1 deletions

diff --git a/instructions.txt b/instructions.txt
index b7d96ef..e06b48a 100644
--- a/instructions.txt
+++ b/instructions.txt
@@ -110,6 +110,16 @@
             Allows you to redefine the DS's joypad and buttons to ZX81 keys.
             Follow the on-screen instructions.
 
+        MACHINE CODE MONITOR
+            Provides access to a basic machine code/memory monitor.  This lets 
+            you watch the ZX81 execute op-codes, or single-step over them.
+
+            Unless you're actually interested in such things you'll never need
+            to go near this option -- it's there to track down emulation bugs
+            as much as anything.
+
+            See the second to last section for more details.
+
         CANCEL
             Cancels the menu.
 
@@ -184,7 +194,41 @@
     register has changed.
 
 
-7. Configuration Options
+7. Machine Code Monitor
+-----------------------
+
+    On starting the machine code monitor the keyboard will go dim and get
+    overlaid with a text display showing you the Z80 instructions about to be
+    executed along with the current states of the registers in the Z80.
+
+    The keyboard is dim, but still on display as the montitor does let you
+    use the keyboard.  Note that all keys are sticky (like the shift key in its
+    default state) and that joypad mappings are ignored.
+
+    With the monitor on display the following joypad keys can be used:
+
+    START       - Toggles between running continuously and single-step mode.
+
+    A           - If in single-step mode then executes the next instruction.
+
+    X           - Display a help page.
+
+    SELECT      - Toggles between the disassembly/register display and a
+                  display of memory.
+
+    L/R         - The shoulder buttons change the address being displayed on
+                  the memory dump.  Hold the Y key at the same time to make
+                  it jump in bigger steps.
+
+    B           - Cycles the value used for the memory dump -- either the
+                  address as set with the shoulder buttons, or one of the
+                  registers: HL, IX, SP, IY, BC or DE.
+
+    Press the config bar at the bottom of the soft keyboard to exit the
+    machine code monitor and return to normal running.
+
+
+8. Configuration Options
 ------------------------
 
     STICKY SHIFT