initial concept of ROM versioning, still needs quite some work

c64/,,config_generic.s

@@ -1,4 +1,6 @@
 
+.const CONFIG_ID = $00 // should be 1 byte, different for each config file!
+
 //
 // Please read CONFIG.md before modifying this file!
 //

c64/,,config_mega65.s

@@ -1,4 +1,6 @@
 
+.const CONFIG_ID = $01 // should be 1 byte, different for each config file!
+
 //
 // Please read CONFIG.md before modifying this file!
 //

c64/,,config_ultimate64.s

@@ -1,4 +1,6 @@
 
+.const CONFIG_ID = $02 // should be 1 byte, different for each config file!
+
 //
 // Please read CONFIG.md before modifying this file!
 //

c64/aliases/,aliases_cpu.s

@@ -3,6 +3,17 @@
 //
 
 
+//
+// This one is not for optimization - but to encourage proper usage of panic screen
+//
+
+.pseudocommand panic code
+{
+	lda code
+	jmp (panic_vector)
+}
+
+
 //
 // Stack manipulation - some CPUs will leave .A unchanged, some will use it as temporary storage, so consider .A trashed
 //

c64/basic/,imports.s

@@ -4,6 +4,9 @@
 #import "KERNAL_combined.sym"
 
 
+.label panic_vector        = KERNAL.panic_vector
+.label rom_revision_kernal = KERNAL.rom_revision_kernal
+
 #if CONFIG_DBG_PRINTF
 .label printf              = KERNAL.printf
 #endif

c64/basic/basic_cold_start.s

@@ -3,6 +3,16 @@
 
 basic_cold_start:
 
+	// Before doing anything, check if we have a compatible Kernal
+
+	ldy #(__rom_revision_basic_end - rom_revision_basic - 1)
+!:
+	lda rom_revision_basic, y
+	cmp rom_revision_kernal, y
+	bne basic_cold_start_rom_mismatch
+	dey
+	bpl !-
+
 	// Setup vectors at $300
 	ldy #$0B
 !:
@@ -32,3 +42,7 @@ basic_cold_start:
 
 	// jump into warm start loop
 	jmp basic_warm_start
+
+basic_cold_start_rom_mismatch:
+
+	panic #$01

c64/basic/bf52.interop

@@ -0,0 +1,2 @@
+
+Special case - we need a constant memory location where we can put an ID and a revision string. According to Compute's Mapping the Commodore 64 (page 117) this area is unused - so a perfect place.

c64/basic/bf52.rom_revision_basic.s

@@ -0,0 +1,25 @@
+
+//
+// !!! PROPOSAL ONLY !!! PROPOSAL ONLY !!! NOT FOR USING EXTERNALLY YET !!!
+//
+//
+// Do not change! Locations of the following data should be constant - now and forever!
+//
+// If you want to integrate Open ROMs support in your emulator, FPGA ccomputer, etc. - this
+// is the official way to recognize the ROM and it's revision.
+//
+
+
+rom_revision_basic:
+
+	// $BF52
+
+	.text "OR"               // Magic string, after "Open ROMs"
+	.byte CONFIG_ID          // Config file ID, might change between revisions
+
+rom_revision_basic_string:
+
+	.text "DEVEL SNAPSHOT"   // Actual ROM revision string
+	.byte $00
+
+__rom_revision_basic_end:

c64/basic/e422.initmsg.jmp.s

@@ -0,0 +1,11 @@
+
+//
+// Well-known BASIC routine, described in:
+//
+// - [CM64] Compute's Mapping the Commodore 64 - page 212
+//
+// Prints the start-up messages
+//
+
+INITMSG:
+	jmp initmsg_real

c64/basic/initmsg_real.s

@@ -1,13 +1,8 @@
 
-//
+// Routine is too long to fit in the original location
-// Well-known BASIC routine, described in:
-//
-// - [CM64] Compute's Mapping the Commodore 64 - page 212
-//
-// Prints the start-up messages
-//
 
-INITMSG:
+
+initmsg_real:
 
 	// Print startup banner, up to 255 characters
 	ldx #$00
@@ -19,6 +14,10 @@ INITMSG:
 	bne !-
 
 !:
+	// Print ROM revision
+	lda #<rom_revision_basic_string
+	ldy #>rom_revision_basic_string
+	jsr STROUT
 
 	// Print PAL/NTSC, if configured
 
@@ -26,6 +25,9 @@ INITMSG:
 	jsr print_pal_ntsc
 #endif
 
+	jsr initmsg_double_return
+	jsr print_return
+
 	// Work out free bytes, display them
 	jsr basic_do_new
     sec
@@ -41,6 +43,6 @@ INITMSG:
 	ldx #34
 	jsr print_packed_message
 
-	// XXX put them into packed message
+initmsg_double_return:
 	jsr print_return
 	jmp print_return

c64/kernal/assets/kernal_messages.s

@@ -17,6 +17,9 @@
 .label __MSG_KERNAL_NTSC          = __kernal_message_ntsc          - __kernal_messages_start
 #endif
 
+.label __MSG_KERNAL_PANIC         = __kernal_message_panic         - __kernal_messages_start
+.label __MSG_KERNAL_PANIC_VERSION = __kernal_message_panic_version - __kernal_messages_start
+
 
 __kernal_messages_start:
 
@@ -51,11 +54,19 @@ __kernal_message_to_hex:
 #if CONFIG_BANNER_PAL_NTSC
 
 __kernal_message_pal:
-	.text "PAL,"
+	.text ", PAL"
 	.byte $80 + $20 // end of string mark + space
 
 __kernal_message_ntsc:
-	.text "NTSC,"
+	.text ", NTSC"
 	.byte $80 + $20 // end of string mark + space
 
 #endif // CONFIG_BANNER_PAL_NTSC
+
+__kernal_message_panic:
+	.text "KERNAL PANI"
+	.byte $80 + $43 // end of string mark + 'C'
+
+__kernal_message_panic_version:
+	.text " - ROM MISMATC"
+	.byte $80 + $48 // end of string mark + 'H'

c64/kernal/panic.s

@@ -0,0 +1,61 @@
+
+//
+// Something terrible happened - show the panic screen
+//
+
+// .A = 0 - just panic, no extra message
+// .A = 1 - ROM version mismatch
+
+panic:
+
+	sei
+	pha
+
+	jsr IOINIT
+	jsr setup_vicii
+	jsr clear_screen
+
+	// XXX disable NMIs
+
+	ldx #$14
+	ldy #$0E
+	jsr plot_set
+
+	ldx #__MSG_KERNAL_PANIC
+	jsr print_kernal_message
+
+	pla
+	beq kernal_panic_infinite_loop
+	pha
+
+	ldx #$02
+	ldy #$02
+	jsr plot_set
+
+	pla
+	pha
+	jsr print_hex_byte
+
+	pla
+	cmp #$01
+	bne kernal_panic_infinite_loop
+
+	ldx #__MSG_KERNAL_PANIC_VERSION
+	jsr print_kernal_message
+
+kernal_panic_infinite_loop:
+	ldx #$00
+	stx VIC_EXTCOL
+
+	ldx #$80
+!:
+	dex
+	bne !-
+
+	ldx #$06
+	stx VIC_EXTCOL
+!:
+	dex
+	bne !-
+
+	beq kernal_panic_infinite_loop // branch always

c64/kernal/xxxx.rom_revision_kernal.s

@@ -0,0 +1,34 @@
+
+//
+// !!! PROPOSAL ONLY !!! PROPOSAL ONLY !!! NOT FOR USING EXTERNALLY YET !!!
+//
+//
+// Do not change! Locations of the following data should be constant - now and forever!
+//
+// If you want to integrate Open ROMs support in your emulator, FPGA ccomputer, etc. - this
+// is the official way to recognize the ROM and it's revision.
+//
+
+
+// XXX we need to find a safe address within $E4D3-$FFFF range, we need 20 bytes
+
+
+panic_vector: 
+
+	// This vector is to be used by non-Kernal ROMs, if they want to complain
+	// about incompatible ROM releases - jump via this vector with .A set to 1
+
+	.byte <panic
+	.byte >panic
+
+rom_revision_kernal:
+
+	.text "OR"               // Magic string, after "Open ROMs"
+	.byte CONFIG_ID          // Config file ID, might change between revisions
+
+rom_revision_kernal_string:
+
+	.text "DEVEL SNAPSHOT"   // Actual ROM revision string
+	.byte $00
+
+__rom_revision_kernal_end: