split Episode3::DataIndex into multiple structures

system/ppc/VersionDetect.s

@@ -3,9 +3,10 @@
 
 # The returned value has the format SSGGRRVV, where:
 #   S = 33 (which represents PSO GC)
-#   G = game (4F (O) = Episodes 1&2, 53 (S) = Episode 3)
+#   G = game (4F (O) = Ep1&2, 53 (S) = Ep3)
 #   R = region (45 (E), 4A (J), or 50 (P))
-#   V = minor version | 30 (30 = 1.00, 31 = 1.01, 32 = 1.02, etc.)
+#   V = minor version | 30 (30 = 1.00, 31 = 1.01, 32 = 1.02, etc.), or 54 for
+#       Trial Edition
 # This results in a 4-character ASCII-printable version code which encodes all
 # of the above information. This value is called specific_version in the places
 # where it's used by the server.
@@ -19,16 +20,23 @@ reloc0:
 start:
   lis    r3, 0x8000
   lwz    r4, [r3]
-  lbz    r5, [r3 + 7]
-  li     r3, -1
-
-  rlwinm r0, r4, 16, 16, 31
-  cmplwi r0, 0x4750
-  bnelr
-
-  lis    r3, 0x3300
-  rlwimi r3, r4, 8, 8, 23
-  rlwimi r3, r5, 0, 24, 31
-  ori    r3, r3, 0x0030
 
+  # For Trial Editions, set the V field to 54; for other versions, set it to
+  # 0x30 | disc_version
+  rlwinm r0, r4, 8, 24, 31
+  cmplwi r0, 0x47  # Check if high byte of game ID is 'G'
+  beq    not_trial
+  cmplwi r0, 0x44  # Check if high byte of game ID is 'D'
+  beq    is_trial
+  li     r3, 0
+  blr
+is_trial:
+  li     r3, 0x0054
+  b      end_trial_check
+not_trial:
+  lbz    r3, [r3 + 7]
+  ori    r3, r3, 0x0030
+end_trial_check:
+  oris   r3, r3, 0x3300  # Set high byte ('3')
+  rlwimi r3, r4, 8, 8, 23  # Set middle two bytes to last to bytes of game ID
   blr