From 58daf2a553241d7da20898c071b2d46226b6c4fc Mon Sep 17 00:00:00 2001
From: FeralChild64 <you@example.com>
Date: Fri, 18 Oct 2019 19:22:21 +0200
Subject: [PATCH] more C128 keyboard support tweaks

---
 CONFIG.md                     |  4 ++--
 c64/,,config_generic.s        |  2 +-
 c64/aliases/,aliases_config.s |  3 ---
 c64/kernal/keyboard/scnkey.s  | 16 ++++++++++++++--
 4 files changed, 17 insertions(+), 8 deletions(-)

diff --git a/CONFIG.md b/CONFIG.md
index 0817127b..d4c868e4 100644
--- a/CONFIG.md
+++ b/CONFIG.md
@@ -123,9 +123,9 @@ Needs about 130 bytes more space in KERNAL segment. If unsure - disable.
 
 ### `CONFIG_KEYBOARD_C128_CAPS_LOCK`
 
-If C128 keyboard support is selected, allows to additionally support it's CAPS LOCK keys. Support is C64-safe (there is a protection against false-positive reading on the C64).
+Allows to use CAPS LOCK key on the C128 keyboard, this is independent from `CONFIG_KEYBOARD_C128`. Support is C64-safe (there is a protection against false-positive reading on the C64).
 
-Needs about 47 bytes more space in KERNAL segment. 
+Needs about 50 bytes more space in KERNAL segment. If unsure - disable.
 
 ### `CONFIG_KEY_REPEAT_DEFAULT`
 
diff --git a/c64/,,config_generic.s b/c64/,,config_generic.s
index 5d062164..be1d0ccd 100644
--- a/c64/,,config_generic.s
+++ b/c64/,,config_generic.s
@@ -50,7 +50,7 @@
 
 // #define CONFIG_LEGACY_SCNKEY
 #define CONFIG_KEYBOARD_C128
-// #define CONFIG_KEYBOARD_C128_CAPS_LOCK
+#define CONFIG_KEYBOARD_C128_CAPS_LOCK
 // #define CONFIG_KEY_REPEAT_DEFAULT
 #define CONFIG_KEY_REPEAT_ALWAYS
 #define CONFIG_KEY_FAST_SCAN
diff --git a/c64/aliases/,aliases_config.s b/c64/aliases/,aliases_config.s
index 0f8c30c0..771b5df1 100644
--- a/c64/aliases/,aliases_config.s
+++ b/c64/aliases/,aliases_config.s
@@ -121,9 +121,6 @@
 #if CONFIG_LEGACY_SCNKEY && CONFIG_KEYBOARD_C128
 	.error "CONFIG_LEGACY_SCNKEY and CONFIG_KEYBOARD_C128 are mutually exclusive"
 #endif
-#if CONFIG_KEYBOARD_C128_CAPS_LOCK && !CONFIG_KEYBOARD_C128
-	.error "CONFIG_KEYBOARD_C128_CAPS_LOCK requires CONFIG_KEYBOARD_C128"
-#endif
 }
 
 
diff --git a/c64/kernal/keyboard/scnkey.s b/c64/kernal/keyboard/scnkey.s
index 4c0575ab..e7c4d736 100644
--- a/c64/kernal/keyboard/scnkey.s
+++ b/c64/kernal/keyboard/scnkey.s
@@ -58,6 +58,9 @@ SCNKEY:
 
 	// First check if this is really a C128 - to avoid false positive
 	lda #$00
+#if !CONFIG_KEYBOARD_C128
+	tax
+#endif
 	sta VIC_XSCAN
 	lda #$FF
 	cmp VIC_XSCAN
@@ -71,6 +74,10 @@ SCNKEY:
 	sta SHFLAG
 !:
 
+#if !CONFIG_KEYBOARD_C128
+	stx VIC_XSCAN                      // disconnect C128 keys if no C128 keyboard is supported
+#endif
+
 #endif
 
 	ldy #(__kb_matrix_bucky_confmask_end - kb_matrix_bucky_confmask - 1)
@@ -297,6 +304,8 @@ scnkey_output_key:
     // !:
 	// lda KEY_TAB_BW                  // bne scnkey_got_petscii if CAPS LOCK is handled
 
+#endif // CONFIG_KEYBOARD_C128_CAPS_LOCK
+
 #if CONFIG_KEYBOARD_C128_CAPS_LOCK
 
 	// Check if we need special handling for a CAPS LOCK key
@@ -304,7 +313,10 @@ scnkey_output_key:
 
 scnkey_handle_caps_lock:
 
-	tax
+#if !CONFIG_KEYBOARD_C128
+	lda (KEYTAB), y
+#endif
+	tax 
 	lda SHFLAG
 	and #(%00000111 + KEY_CAPS_LOCK)
 	cmp #KEY_CAPS_LOCK
@@ -324,7 +336,7 @@ scnkey_handle_caps_lock:
 
 #endif // CONFIG_KEYBOARD_C128_CAPS_LOCK
 
-#else
+#if !CONFIG_KEYBOARD_C128 && !CONFIG_KEYBOARD_C128_CAPS_LOCK
 
 	lda (KEYTAB), y