address mode optimizations, updated credits

CREDITS.md

@@ -28,6 +28,7 @@
 
 * Gábor Lénárt - for [his work](https://github.com/lgblgblgb/xemu) on XEMU MEGA65 emulator
 * Hernán Di Pietro - for [his work](https://github.com/hernandp/xemu) on XEMU MEGA65 emulator
+* Marco Baye - for [ACME](https://sourceforge.net/projects/acme-crossass) cross-assembler
 * Mads Nielsen - for the [Kick Assembler](http://www.theweb.dk/KickAssembler/Main.html#frontpage)
 * Simon Jameson - for his Kick Assembler [pseudocommands](https://github.com/smnjameson/M65_KickAsm_PseudoCommands) for MEGA65 CPU support
 

src/kernal/,kernal_aliases.s

@@ -0,0 +1,23 @@
+
+;
+; Aliases for legacy keyboard scan routine
+;
+
+!ifdef CONFIG_LEGACY_SCNKEY {
+
+	; Low memory variables
+
+	; Reuse RS232 variables, since they should not be used by other things.
+	; Carefully avoid $A7 which is used by 64NET
+	!addr KeyQuantity       = $A8  ; 1 byte
+	!addr BufferNew         = $A9  ; 3 bytes
+	!addr TempZP            = $B6  ; 1 byte
+	; These should be initialized in CINT to $FF
+	!addr BufferQuantity    = $B4  ; 1 byte
+	!addr BufferOld         = $293 ; 3 bytes
+	!addr Buffer 	         = $297 ; 4 bytes
+
+	; $250-$258 is the 81st - 88th characters in BASIC input, a carry over from VIC-20
+	; and not used on C64, so safe for us to use, probably.
+	!addr ScanResult = $250 ; 8 bytes
+}

src/kernal/keyboard/scnkey_legacy.s

@@ -59,24 +59,10 @@
 
 ; ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
 
-	; Low memory variables
 
-	; Reuse RS232 variables, since they should not be used by other things.
-	; Carefully avoid $A7 which is used by 64NET
-	!addr KeyQuantity       = $A8  ; 1 byte
-	!addr BufferNew         = $A9  ; 3 bytes
-	!addr TempZP            = $B6  ; 1 byte
-	; These should be initialized in CINT to $FF
-	!addr BufferQuantity    = $B4  ; 1 byte
-	!addr BufferOld         = $293 ; 3 bytes
-	!addr Buffer 	         = $297 ; 4 bytes
-
-	; $250-$258 is the 81st - 88th characters in BASIC input, a carry over from VIC-20
-	; and not used on C64, so safe for us to use, probably.
-	!addr ScanResult = $250 ; 8 bytes
 
 	; Operational Variables
-	!addr MaxKeyRollover = 3
+	!set MaxKeyRollover = 3
 
 SCNKEY: