added CAPS LOCK key support on C128

CONFIG.md

@@ -113,13 +113,19 @@ Original keyboard support routine is just horrible. It does nothing to prevent g
 
 Uses old Open ROMs keyboard scanning routine, which is basically example routine by TWW/CTR, hacked to work within Kernal. It's greatest advantage is multi-key rollover, it's disadvantages - it's much less compatible (uses several bytes of memory which are normally free for user software - thus, it is considered legacy for now), does not support all the system variables (`RPTFLG` and `KEYLOG` are unsupported), and ignores the configuration options - this can be changed, but it requires some effort.
 
-Needs 70-250 more space in KERNAL segment (depending on the features enabled for current default routine). If unsure - disable.
+Needs 30-250 more space in KERNAL segment (depending on the features enabled for current default routine). If unsure - disable.
 
 ### `CONFIG_KEYBOARD_C128`
 
 Allows to use additional keys found on the C128 keyboard. NOTE: might be buggy, on VICE emulator I can't get all the keys working.
 
-Needs about 125 bytes more space in KERNAL segment. If unsure - disable.
+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).
+
+Needs about 47 bytes more space in KERNAL segment. 
 
 ### `CONFIG_KEY_REPEAT_DEFAULT`
 

c64/,,config_generic.s

@@ -50,6 +50,7 @@
 
 // #define CONFIG_LEGACY_SCNKEY
 #define CONFIG_KEYBOARD_C128
+// #define CONFIG_KEYBOARD_C128_CAPS_LOCK
 // #define CONFIG_KEY_REPEAT_DEFAULT
 #define CONFIG_KEY_REPEAT_ALWAYS
 #define CONFIG_KEY_FAST_SCAN

c64/,,config_mega65.s

@@ -52,6 +52,7 @@
 
 #define CONFIG_LEGACY_SCNKEY
 // #define CONFIG_KEYBOARD_C128
+// #define CONFIG_KEYBOARD_C128_CAPS_LOCK
 // #define CONFIG_KEY_REPEAT_DEFAULT
 // #define CONFIG_KEY_REPEAT_ALWAYS
 #define CONFIG_KEY_FAST_SCAN

c64/,,config_ultimate64.s

@@ -50,6 +50,7 @@
 
 // #define CONFIG_LEGACY_SCNKEY
 // #define CONFIG_KEYBOARD_C128
+// #define CONFIG_KEYBOARD_C128_CAPS_LOCK
 // #define CONFIG_KEY_REPEAT_DEFAULT
 // #define CONFIG_KEY_REPEAT_ALWAYS
 #define CONFIG_KEY_FAST_SCAN

c64/aliases/,aliases_config.s

@@ -115,6 +115,19 @@
 
 
 
+// Check if keyboard options are correct
+
+{
+#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
+}
+
+
+
 // Handle processor configuration
 
 #if CONFIG_CPU_WDC_65C02 || CONFIG_CPU_CSG_65CE02 || CONFIG_CPU_WDC_65816

c64/aliases/,aliases_petscii_codes.s

@@ -15,8 +15,9 @@
 .const KEY_FLAG_SHIFT   = %00000001
 .const KEY_FLAG_VENDOR  = %00000010
 .const KEY_FLAG_CTRL    = %00000100
-.const KEY_FLAG_ALT     = %00001000  // C65 / C128                            XXX implement this
-.const KEY_FLAG_NO_SCRL = %00100000  // C65 / C128, Open ROMs unofficial      XXX implement this
+.const KEY_FLAG_ALT     = %00001000  // C65 / C128
+.const KEY_CAPS_LOCK    = %00010000  // C65 / C128
+.const KEY_FLAG_NO_SCRL = %00100000  // C65 / C128, Open ROMs unofficial
 
 
 // Note - the following PETSCII codes are currently unassigned, can be used for further extensions:

c64/kernal/keyboard/scnkey.s

@@ -52,7 +52,26 @@ SCNKEY:
 
 #endif
 
-	// Retrieve SHIFT / VENDOR / CTRL status
+	// Retrieve SHIFT / VENDOR / CTRL / ALT / CAPS LOCK status
+
+#if CONFIG_KEYBOARD_C128_CAPS_LOCK
+
+	// First check if this is really a C128 - to avoid false positive
+	lda #$00
+	sta VIC_XSCAN
+	lda #$FF
+	cmp VIC_XSCAN
+	beq !+                             // branch if C64, C128 will keep some bits cleared
+
+	lda CPU_R6510
+	and #$40
+	bne !+                             // branch if no CAPS LOCK
+
+	lda #KEY_CAPS_LOCK
+	sta SHFLAG
+!:
+
+#endif
 
 	ldy #(__kb_matrix_bucky_confmask_end - kb_matrix_bucky_confmask - 1)
 scnkey_bucky_loop:
@@ -269,14 +288,41 @@ scnkey_output_key:
 	// XXX this will be needed for extended screen editor
 
 	// cmp KEY_TAB_FW                  // special handling for SHIFT+TAB
-	// bne scnkey_got_petscii
+	// bne scnkey_got_petscii          // XXX or to scnkey_handle_caps_lock
 	// lda SHFLAG                      // special handling for SHIFT+TAB
 	// and #KEY_FLAG_SHIFT
 	// bne !+
 	// lda KEY_TAB_FW
 	// bne scnkey_got_petscii          // branch alWAYS 
     // !:
-	// lda KEY_TAB_BW
+	// lda KEY_TAB_BW                  // bne scnkey_got_petscii if CAPS LOCK is handled
+
+#if CONFIG_KEYBOARD_C128_CAPS_LOCK
+
+	// Check if we need special handling for a CAPS LOCK key
+	// This is shorter than a separate set of tables
+
+scnkey_handle_caps_lock:
+
+	tax
+	lda SHFLAG
+	and #(%00000111 + KEY_CAPS_LOCK)
+	cmp #KEY_CAPS_LOCK
+	bne !+                             // branch if no special CAPS LOCK handling needed
+
+	cpx #$41                           // 'A'
+	bcc !+
+	cpx #$5B                           // 'Z' + 1
+	bcs !+
+
+	txa
+	clc
+	adc #$20                           // turn lowercase into uppercase
+	tax 
+!:
+	txa
+
+#endif // CONFIG_KEYBOARD_C128_CAPS_LOCK
 
 #else