Updated docs

README.md

@@ -210,6 +210,18 @@ Lots of games work:
 | Yar's Revenge          | Seems to play fine.                                                      |
 | Zaxxon                 | Seems to play fine.                                                      |
 
+Rendering RAM traces
+--------------------
+In `stellarator.cabal` set `-DTRACE` to 1 instead of 0. Now rebuild.
+The `W` key will now write a trace of all RAM written to.
+Usually hit trace after about 30 seconds or so.
+Then run a command like
+```
+    c++ -std=c++11 -O3 -o trace trace.cpp && ./trace && open trace.bmp
+```
+and it'll render a trace that looks a bit like:
+![RAM trace](docs/trace.png?raw=true "RAM trace")
+
 Some notes on writing an emulator in Haskell
 ---------------------------------------------
 

Stellarator.cabal

@@ -19,7 +19,7 @@ library
   hs-source-dirs:      src
   ghc-options:         -O5 -Wall -fwarn-missing-signatures -ddump-simpl -ddump-asm
   extensions: CPP
-  cpp-options: -DTRACE=0
+  cpp-options: -DTRACE=1
   extensions:          
   exposed-modules:     TIAColors, Binary, Core, Disasm,
                        DebugCmd, Memory, Asm, DebugState, Atari2600, Debugger, Metrics, BitManips, Emulation, VideoOps, Display, Keys, Events
@@ -44,7 +44,7 @@ executable stellarator-exe
   main-is:             Main.hs
   ghc-options:         -O5 -Wall -fwarn-missing-signatures -ddump-simpl -ddump-asm 
   extensions: CPP
-  cpp-options: -DTRACE=0
+  cpp-options: -DTRACE=1
   build-depends:       base
                      , sdl2
                      , bytestring