add Mission on Thuderhead to the collection

res/GAMES.CONF

@@ -146,6 +146,7 @@
 1000,MINER.2049ER
 1001,MINER.2049.II=Miner 2049er II
 1001,MINGS.CHALLENGE=Ming's Challenge
+1000,THUNDERHEAD=Mission on Thunderhead
 0001,MONTEZUMA=Montezuma's Revenge
 0001,MOON.PATROL
 0000,MR.COOL=Mr. Cool

res/TITLE.HGR/_FileInformation.txt

@@ -222,6 +222,7 @@ THEXDER=Type(06),AuxType(4000),Access(C3)
 THIEF=Type(06),AuxType(4000),Access(C3)
 THRESHOLD=Type(06),AuxType(4000),Access(C3)
 THUNDER.BOMBS=Type(06),AuxType(4000),Access(C3)
+THUNDERHEAD=Type(06),AuxType(4000),Access(C3)
 TOMAHAWK=Type(06),AuxType(4000),Access(C3)
 TRACK.AND.FIELD=Type(06),AuxType(4000),Access(C3)
 TRIAD=Type(06),AuxType(4000),Access(C3)

src/prelaunch/thunderhead.a

@@ -0,0 +1,23 @@
+;license:MIT
+;(c) 2020 by qkumba
+
+!cpu 6502
+!to "build/PRELAUNCH/THUNDERHEAD",plain
+*=$106
+
+    !source "src/prelaunch/common.a"
+
+         +ENABLE_ACCEL
+         lda   #<callback
+         sta   $2046
+         lda   #>callback
+         sta   $2047
+         jmp   $800        ; decompress
+
+callback
+         jsr   DisableAccelerator
+         jmp   $204B
+
+!if * > $1C0 {
+  !error "code is too large, ends at ", *
+}