CV64: Allow Holding Z to Use the Regular Shimmy Speed (#4730)

* Add the shimmy modifier hack.

* Update the Increase Shimmy Speed option description.

---------

Co-authored-by: Exempt-Medic <60412657+Exempt-Medic@users.noreply.github.com>

worlds/cv64/data/patches.py

@@ -2893,3 +2893,18 @@ dog_bite_ice_trap_fix = [
     0x25291CB8,  # ADDIU T1, T1, 0x1CB8
     0x01200008   # JR    T1
 ]
+
+shimmy_speed_modifier = [
+    # Increases the player's speed while shimmying as long as they are not holding down Z. If they are holding Z, it
+    # will be the normal speed, allowing it to still be used to set up any tricks that might require the normal speed
+    # (like Left Tower Skip).
+    0x3C088038,  # LUI   T0, 0x8038
+    0x91087D7E,  # LBU   T0, 0x7D7E (T0)
+    0x31090020,  # ANDI  T1, T0, 0x0020
+    0x3C0A800A,  # LUI   T2, 0x800A
+    0x240B005A,  # ADDIU T3, R0, 0x005A
+    0x55200001,  # BNEZL T1,     [forward 0x01]
+    0x240B0032,  # ADDIU T3, R0, 0x0032
+    0xA14B3641,  # SB    T3, 0x3641 (T2)
+    0x0800B7C3   # J     0x8002DF0C
+]

worlds/cv64/options.py

@@ -424,6 +424,7 @@ class PantherDash(Choice):
 class IncreaseShimmySpeed(Toggle):
     """
     Increases the speed at which characters shimmy left and right while hanging on ledges.
+    Hold Z to use the regular speed in case it's needed to do something.
     """
     display_name = "Increase Shimmy Speed"
 

worlds/cv64/rom.py

@@ -607,9 +607,10 @@ class CV64PatchExtensions(APPatchExtension):
         rom_data.write_int32(0xAA530, 0x080FF880)  # J 0x803FE200
         rom_data.write_int32s(0xBFE200, patches.coffin_cutscene_skipper)
 
-        # Increase shimmy speed
+        # Shimmy speed increase hack
         if options["increase_shimmy_speed"]:
-            rom_data.write_byte(0xA4241, 0x5A)
+            rom_data.write_int32(0x97EB4, 0x803FE9F0)
+            rom_data.write_int32s(0xBFE9F0, patches.shimmy_speed_modifier)
 
         # Disable landing fall damage
         if options["fall_guard"]: