From bb2b4981b877bd152143159c8465ef41c946ad5d Mon Sep 17 00:00:00 2001
From: FeralChild64 <you@example.com>
Date: Sun, 13 Oct 2019 20:39:05 +0200
Subject: [PATCH] new SCNKEY is functionning, but probably needs different
 matrix format

---
 STATUS.md                    |  6 ++---
 c64/kernal/e50a.plot.s       |  4 +--
 c64/kernal/keyboard/scnkey.s | 49 +++++++++++++++++++++++++++++++-----
 3 files changed, 48 insertions(+), 11 deletions(-)

diff --git a/STATUS.md b/STATUS.md
index 6c5ebc5b..4195a6ba 100644
--- a/STATUS.md
+++ b/STATUS.md
@@ -62,7 +62,7 @@ Note: vectors at `$0300` are not supported yet - for now only the locations belo
 | `(00306)` | `$A71A`    | `QPLOP`    | NOT DONE | some implementation exists, but not connected here |
 | `(00308)` | `$A7E4`    | `GONE`     | NOT DONE | some implementation exists, but not connected here |
 | `(0030A)` | `$AE86`    | `EVAL`     | NOT DONE | some implementation exists, but not connected here |
-| `($A000)` |            | cold start | PARTIAL  |                                                    |
+| `($A000)` | `$E394`    | cold start | PARTIAL  |                                                    |
 | `($A002)` |            | warm start | PARTIAL  |                                                    |
 
 <br />
@@ -109,7 +109,7 @@ NOTE: Even the 'DONE' routines won't support features described as missing in on
 | `$FF96`   |            | `TKSA`      | DONE     |                                                    |
 | `$FF99`   |            | `MEMTOP`    | DONE     |                                                    |
 | `$FF9C`   |            | `MEMBOT`    | DONE     |                                                    |
-| `$FF9F`   |            | `SCNKEY`    | DONE     | could be better integrated with ROM (aliases)      |
+| `$FF9F`   |            | `SCNKEY`    | PARTIAL  | future complete version has compatibility problems |
 | `$FFA2`   |            | `SETTMO`    | DONE     |                                                    |
 | `$FFA5`   |            | `ACPTR`     | DONE     |                                                    |
 | `$FFA8`   |            | `CIOUT`     | DONE     |                                                    |
@@ -138,7 +138,7 @@ NOTE: Even the 'DONE' routines won't support features described as missing in on
 | `$FFE7`   | `$F32F`    | `CLALL`     | DONE     |                                                    |
 | `$FFEA`   |            | `UDTIM`     | DONE     |                                                    |
 | `$FFED`   |            | `SCREEN`    | DONE     |                                                    |
-| `$FFF0`   | `$E50A`    | `PLOT`      | PARTIAL  |                                                    |
+| `$FFF0`   | `$E50A`    | `PLOT`      | DONE     |                                                    |
 | `$FFF3`   |            | `IOBASE`    | DONE     |                                                    |
 | `($FFFA)` |            | NMI vec     | PARTIAL  |                                                    |
 | `($FFFC)` |            | RESET vec   | PARTIAL  |                                                    |
diff --git a/c64/kernal/e50a.plot.s b/c64/kernal/e50a.plot.s
index ae9d32ff..a36dfc08 100644
--- a/c64/kernal/e50a.plot.s
+++ b/c64/kernal/e50a.plot.s
@@ -17,16 +17,16 @@ PLOT:
 	// - 'Duotris' game calls $E50C during startup screen initialization
 
 plot_set:
+
 	sty PNTR
 	stx TBLX
 
 	jsr screen_calculate_line_pointer
 
-	// XXX cursor blink might need to be handled too
-
 	// FALLTROUGH to save one byte on RTS
 
 plot_get:
+
 	ldy PNTR
 	ldx TBLX
 	rts
diff --git a/c64/kernal/keyboard/scnkey.s b/c64/kernal/keyboard/scnkey.s
index 099ca857..a2316b34 100644
--- a/c64/kernal/keyboard/scnkey.s
+++ b/c64/kernal/keyboard/scnkey.s
@@ -20,6 +20,7 @@
 // - MODE    - flag, whether charset toggle (SHIFT+VENDOR) is allowed
 
 
+// XXX add RPTFLG support
 // XXX add Commodore 128 keyboard support
 // XXX add Commodore 65 keybopard support
 // XXX add support for using joystick to move sursor keys
@@ -58,7 +59,7 @@ scnkey_bucky_loop:
 	sta CIA1_PRA
 	lda kb_matrix_bucky_testmask, y
 	and CIA1_PRB
-	bne !+ // not pressed
+	bne !+                          // not pressed
 	lda SHFLAG
 	ora kb_matrix_bucky_shflag, y
 	sta SHFLAG
@@ -68,9 +69,14 @@ scnkey_bucky_loop:
 
 	// Set KEYTAB vector
 
-	jsr scnkey_via_keylog // XXX for some CPUs we have indirect jsr
+	jsr via_keylog // XXX for some CPUs we have indirect jsr
+
+	// Check if we have free space in the keyboard buffer
+
+	lda NDX
+	cmp XMAX
+	bcs scnkey_no_keys             // no space in keyboard buffer - do not waste time
 
-	// XXX check if there is space in keyboard buffer
 	// XXX check for joystick activity
 
 	// Scan the keyboard matrix
@@ -113,7 +119,7 @@ scnkey_matrix_loop_next:
 
 scnkey_no_keys:
 
-	// XXX
+	// Mark no key press
 
 	lda #$40 // XXX adapt value for C128 and C65 keyboards
 	sta LSTX
@@ -122,18 +128,49 @@ scnkey_no_keys:
 
 scnkey_got_key: // .X should now contain the key offset in matrix pointed by KEYTAB
 
+	cpx LSTX
+	beq scnkey_handle_repeat       // branch if the same key as previously
+	stx LSTX
+
+	// Reset key repeat counters - see [CM64] page 58
+
+	lda #$04
+	sta KOUNT
+	lda #$10
+	sta DELAY
+
+	// FALLTROUGH
+
+scnkey_output_key:
+
+	// Output PETSCII code to the keyboard buffer
+
+	txa // XXX switch registers!!!
+	tay
+
+	lda (KEYTAB), y
+	beq scnkey_no_keys             // branch if we have no PETSCII code for this key
+	ldy NDX
+	sta KEYD, y
+	inc NDX
+
+	rts
+
+scnkey_handle_repeat:
+
 	// Handle repeat timer
 
-	.break
 	lda KOUNT
 	beq !+
 	dec KOUNT
 !:
 
 	// XXX
+
 	rts
 
-scnkey_via_keylog:
+via_keylog:
 	jmp (KEYLOG)
 
+
 #endif // no CONFIG_SCNKEY_TWW_CTR