From f97baeb88e55cf6834971688cf52514488ba4cb1 Mon Sep 17 00:00:00 2001
From: frankmilliron <34376619+frankmilliron@users.noreply.github.com>
Date: Fri, 4 Sep 2020 08:20:37 -0700
Subject: [PATCH] fix Fastchip joystick detection on older firmware (#338)

---
 src/hw.accel.a    | 15 ---------------
 src/hw.joystick.a | 48 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 48 insertions(+), 15 deletions(-)

diff --git a/src/hw.accel.a b/src/hw.accel.a
index cf5090707..efc20d80f 100755
--- a/src/hw.accel.a
+++ b/src/hw.accel.a
@@ -125,8 +125,6 @@ FC_UNLOCK       =    $6A     ; write 4 times
 FC_LOCK         =    $A6
 FC_1MHZ         =    9
 FC_ON           =    40      ; doco says 16.6Mhz
-FC_SPKR         =    2
-FC_HIFI         =    4
 
 ; TransWarp I
 ; may overlap with paddle trigger
@@ -214,19 +212,6 @@ build_setspeed
          rts
 
 build_addon
-         lda   #FC_UNLOCK            ; change Fastchip speaker setting to 'HIFI'
-         sta   fc_lock               ; (improves sound on most games)
-         sta   fc_lock               ; (setting reverts on power cycle)
-         sta   fc_lock
-         sta   fc_lock
-         sta   fc_enable
-         lda   #FC_SPKR
-         sta   fc_config
-         lda   #FC_HIFI
-         sta   fc_data
-         lda   #FC_LOCK
-         sta   fc_lock
-
          lda   #<addon
          ldy   #>addon
          ldx   #(end_addon-addon)
diff --git a/src/hw.joystick.a b/src/hw.joystick.a
index 48abede5f..1260eee86 100644
--- a/src/hw.joystick.a
+++ b/src/hw.joystick.a
@@ -13,7 +13,55 @@
 ; (c) 1989 Broderbund Software
 ; https://github.com/jmechner/Prince-of-Persia-Apple-II/blob/master/01%20POP%20Source/Source/GRAFIX.S#L1225
 ;------------------------------------------------------------------------------
+; Fastchip firmware 0.4b-compatibility fix by Frank M. (0.5b seems unaffected)
+;------------------------------------------------------------------------------
 HasJoystick
+
+         lda   $FBB3
+         cmp   #$06
+         bne   ++
+         lda   $FBC0
+         cmp   #$E0
+         beq   +             ; test for Fastchip on enhanced //e
+         cmp   #$EA
+         beq   +             ; test for Fastchip on non-enhanced //e
+         jmp   ++
+
++        ; FASTChip
+fc_lock         =    $C06A
+fc_enable       =    $C06B
+fc_config       =    $C06E
+fc_data         =    $C06F
+FC_UNLOCK       =    $6A     ; write 4 times
+FC_LOCK         =    $A6
+FC_SPKR         =    2       ; speaker delay register
+FC_HIFI         =    4       ; set to 'HIFI'
+FC_JOY          =    3       ; joystick delay register
+FC_LONG         =    2       ; set to 'LONG'
+
+         lda   #FC_UNLOCK
+         sta   fc_lock
+         sta   fc_lock
+         sta   fc_lock
+         sta   fc_lock
+         sta   fc_enable
+         lda   fc_enable             ; 00 if no fastchip
+         cmp   #$80                  ; 80 if Fastchip normal
+         bne   ++                    ; A0 if Fastchip disabled
+
+         lda   #FC_JOY               ; change Fastchip joystick delay setting to 'LONG'
+         sta   fc_config             ; (improves joystick detection)
+         lda   #FC_LONG
+         sta   fc_data
+
+         lda   #FC_SPKR              ; change Fastchip speaker delay setting to 'HIFI'
+         sta   fc_config             ; (improves sound on most games)
+         lda   #FC_HIFI
+         sta   fc_data
+         
+         lda   #FC_LOCK              ; (settings revert on power cycle)
+         sta   fc_lock
+++
          lda   #0
          sta   @joyX
          sta   @joyY