several features are now optional, added legacy BASIC memory model

CONFIG.md

@@ -0,0 +1,58 @@
+
+# Configuring the build
+
+It's not possible to provide ROM builds that suit everyone needs - therefore configuration files were introduced, separately for each of the hardware targets:
+
+* [`c64/,,config_generic.s`](c64/,,config_generic.s)
+* [`c64/,,config_mega65.s`](c64/,,config_mega65.s)
+* [`c64/,,config_ultimate64.s`](c64/,,config_ultimate64.s)
+
+Just edit them and recompile the project. To enable particular option - uncomment it by removing leading `//` from before `#define` directive (as you probably guessed, commenting out disables it). Some options are followed by constants - you can change them too to further fine-tune the build.
+
+Note however, that features do not came for free - enabling them needs some additional ROM space (in BASIC segment, in KERNAL segment, or in both), which is VERY limited on the target machines. Some options might be unavailable for speecific targets - read the comments in the configuration files. Some options might also carry compatibility and/or performance hit - so choose wisely.
+
+Sane defaults are already present - different for each target.
+
+## Memory models
+
+Different layouts of memory are possible - but they can be selected at compile time only.
+
+### `CONFIG_MEMORY_MODEL_38K`
+
+Memory model the original machine uses - memory available for BASIC ends at `$9FFF`, just before the first block of ROM. The fastest and the most compatible, but gives the least memory for BASIC. If unsure - select this one.
+
+### `CONFIG_MEMORY_MODEL_46K` and `CONFIG_MEMORY_MODEL_50K`
+
+Planned for the future - not available yet.
+
+### `CONFIG_MEMORY_MODEL_60K`
+
+Uses RAM under BASIC, I/O and KERNAL, takes over `$C000`-`$CFFF` area requires special helper routines installed in `$2A7`-`$2FF` area (normally unused and free for the user). Gives the most free memory for BASIC programs, but it's the slowest and the least compatible model.
+
+TODO: ROM memory consumption
+
+## Multiple SID support
+
+The SID is a sound chip - original machine had one installed. However, mods exists to add more of them for improved sound capabilitiee. Emulators and FPGA machines typically allow to simulate more than one too. Unfortunately, there is no standard regarding how these additional chips are visible in the processor address space, and there is no sane way to detect it - thus, it has to be configurable.
+
+The SID support in the ROM is very limited - it only disables the sound during startup or warm restart (when STOP+RESTORE is pressed or BRK assembler instruction is executed).
+
+### `CONFIG_SID_2ND` and `CONFIG_SID_3RD` 
+
+Each of them add support for one additional SID - addresses should be given in `CONFIG_SID_2ND_ADDRESS` and `CONFIG_SID_3RD_ADDRESS`, respectively.
+
+Each of these options needs 8 bytes in KERNAL segment.
+
+### `CONFIG_SID_D4XX` and `CONFIG_SID_D5XX`
+
+Cause the system to support SIDs in `$D4xx` and `$D5xx` ranges, respectively.
+
+Each of them needs a couple of bytes in KERNAL segment - but they can share some code, and `$D4xx` range support replaces the standard `$D400` address handling, so exact amount depends on the exact configuration.
+
+## Miscelaneous features
+
+### `CONFIG_DOS_WEDGE`
+
+If enabled, a simple DOS wedge is available from the direct mode - supports `@<drive_number>`, `@<command>`, `@$`, `@$<params>` and `@` commands.
+
+Feature needs about 330 bytes in BASIC segment.

Makefile

@@ -15,6 +15,11 @@ SRCDIR_KERNAL_ultimate64 = $(SRCDIR_KERNAL_COMMON) c64/kernal/,target_ultimate64
 
 SRC_TOOLS  = $(wildcard src/tools/*.c,src/tools/*.cc)
 
+# Generated files
+
+GEN_BASIC  = build/,generated/packed_messages.s
+GEN_KERNAL =
+
 # List of tools
 
 TOOL_COLLECT_DATA   = build/tools/collect_data
@@ -84,13 +89,13 @@ build/chargen.rom: $(TOOL_PNGPREPARE) assets/8x8font.png
 
 # Dependencies - BASIC and KERNAL
 
-build/target_generic/OUTB.BIN:    $(TOOL_ASSEMBLER) $(TOOL_BUILD_SEGMENT) $(SRCDIR_BASIC_generic)     $(foreach dir,$(SRCDIR_BASIC_generic),$(wildcard $(dir)/*.s)) build/,generated/packed_messages.s
+build/target_generic/OUTB.BIN:    $(TOOL_ASSEMBLER) $(TOOL_BUILD_SEGMENT) $(GEN_BASIC)  $(SRCDIR_BASIC_generic)     c64/,,config_generic.s    $(foreach dir,$(SRCDIR_BASIC_generic),$(wildcard $(dir)/*.s))
-build/target_mega65/OUTB.BIN:     $(TOOL_ASSEMBLER) $(TOOL_BUILD_SEGMENT) $(SRCDIR_BASIC_mega65)      $(foreach dir,$(SRCDIR_BASIC_mega65),$(wildcard $(dir)/*.s)) build/,generated/packed_messages.s
+build/target_mega65/OUTB.BIN:     $(TOOL_ASSEMBLER) $(TOOL_BUILD_SEGMENT) $(GEN_BASIC)  $(SRCDIR_BASIC_mega65)      c64/,,config_mega65.s     $(foreach dir,$(SRCDIR_BASIC_mega65),$(wildcard $(dir)/*.s))
-build/target_ultimate64/OUTB.BIN: $(TOOL_ASSEMBLER) $(TOOL_BUILD_SEGMENT) $(SRCDIR_BASIC_ultimate64)  $(foreach dir,$(SRCDIR_BASIC_ultimate64),$(wildcard $(dir)/*.s)) build/,generated/packed_messages.s
+build/target_ultimate64/OUTB.BIN: $(TOOL_ASSEMBLER) $(TOOL_BUILD_SEGMENT) $(GEN_BASIC)  $(SRCDIR_BASIC_ultimate64)  c64/,,config_ultimate64.s $(foreach dir,$(SRCDIR_BASIC_ultimate64),$(wildcard $(dir)/*.s))
 
-build/target_generic/OUTK.BIN:    $(TOOL_ASSEMBLER) $(TOOL_BUILD_SEGMENT) $(SRCDIR_KERNAL_generic)    $(foreach dir,$(SRCDIR_KERNAL_generic),$(wildcard $(dir)/*.s))
+build/target_generic/OUTK.BIN:    $(TOOL_ASSEMBLER) $(TOOL_BUILD_SEGMENT) $(GEN_KERNAL) $(SRCDIR_KERNAL_generic)    c64/,,config_generic.s    $(foreach dir,$(SRCDIR_KERNAL_generic),$(wildcard $(dir)/*.s))
-build/target_mega65/OUTK.BIN:     $(TOOL_ASSEMBLER) $(TOOL_BUILD_SEGMENT) $(SRCDIR_KERNAL_mega65)     $(foreach dir,$(SRCDIR_KERNAL_mega65),$(wildcard $(dir)/*.s))
+build/target_mega65/OUTK.BIN:     $(TOOL_ASSEMBLER) $(TOOL_BUILD_SEGMENT) $(GEN_KERNAL) $(SRCDIR_KERNAL_mega65)     c64/,,config_mega65.s     $(foreach dir,$(SRCDIR_KERNAL_mega65),$(wildcard $(dir)/*.s))
-build/target_ultimate64/OUTK.BIN: $(TOOL_ASSEMBLER) $(TOOL_BUILD_SEGMENT) $(SRCDIR_KERNAL_ultimate64) $(foreach dir,$(SRCDIR_KERNAL_ultimate64),$(wildcard $(dir)/*.s))
+build/target_ultimate64/OUTK.BIN: $(TOOL_ASSEMBLER) $(TOOL_BUILD_SEGMENT) $(GEN_KERNAL) $(SRCDIR_KERNAL_ultimate64) c64/,,config_ultimate64.s $(foreach dir,$(SRCDIR_KERNAL_ultimate64),$(wildcard $(dir)/*.s))
 
 build/target_generic/newrom:      build/target_generic/OUTB.BIN     build/target_generic/OUTK.BIN
 build/target_mega65/newrom:       build/target_mega65/OUTB.BIN      build/target_mega65/OUTK.BIN
@@ -114,13 +119,13 @@ build/,generated/packed_messages.s: $(TOOL_COMPRESS_TEXT)
 build/target_%/OUTB.BIN:
 	@mkdir -p build/target_$*
 	@rm -f $@* build/target_$*/BASIC*
-	@$(TOOL_BUILD_SEGMENT) -s BASIC -i BASIC-$* -o OUTB.BIN -t build/target_$* -l a000 -h e4d2 $(SRCDIR_BASIC_$*) build/,generated/packed_messages.s
+	@$(TOOL_BUILD_SEGMENT) -s BASIC -i BASIC-$* -o OUTB.BIN -t build/target_$* -l a000 -h e4d2 c64/,,config_$*.s $(SRCDIR_BASIC_$*) $(GEN_BASIC)
 
 .PRECIOUS: build/target_%/OUTK.BIN
 build/target_%/OUTK.BIN:
 	@mkdir -p build/target_$*
 	@rm -f $@* build/target_$*/KERNAL*
-	@$(TOOL_BUILD_SEGMENT) -s KERNAL -i KERNAL-$* -o OUTK.BIN -t build/target_$* -l e4d3 -h ffff $(SRCDIR_KERNAL_$*)
+	@$(TOOL_BUILD_SEGMENT) -s KERNAL -i KERNAL-$* -o OUTK.BIN -t build/target_$* -l e4d3 -h ffff c64/,,config_$*.s $(SRCDIR_KERNAL_$*) $(GEN_KERNAL)
 
 .PRECIOUS: build/target_%/newrom
 build/target_%/newrom:
@@ -148,12 +153,21 @@ build/newc65.rom: build/kernal_mega65.rom build/basic_mega65.rom build/chargen.r
 test: build/kernal_generic.rom build/basic_generic.rom
 	x64 -kernal build/kernal_generic.rom -basic build/basic_generic.rom -8 empty.d64
 
+test_generic: build/kernal_generic.rom build/basic_generic.rom
+	x64 -kernal build/kernal_generic.rom -basic build/basic_generic.rom -8 empty.d64
+
+test_mega65: build/kernal_mega65.rom build/basic_mega65.rom
+	x64 -kernal build/kernal_mega65.rom -basic build/basic_mega65.rom -8 empty.d64
+
+test_ultimate64: build/kernal_ultimate64.rom build/basic_ultimate64.rom
+	x64 -kernal build/kernal_ultimate64.rom -basic build/basic_ultimate64.rom -8 empty.d64
+
+test_m65: build/newc65
+	m65 -b ../mega65-core/bin/mega65r1.bit -k ../mega65-core/bin/KICKUP.M65 -R build/newc65.rom -4
+
 testremote: build/kernal_generic.rom build/basic_generic.rom
 	x64 -kernal build/kernal_generic.rom -basic build/basic_generic.rom -remotemonitor
 
-testm65: build/newc65
-	m65 -b ../mega65-core/bin/mega65r1.bit -k ../mega65-core/bin/KICKUP.M65 -R build/newc65.rom -4
-
 testsimilarity: build/target_generic/newrom $(TOOL_SIMILARITY)
 	$(TOOL_SIMILARITY) kernal build/target_generic/newrom
 	$(TOOL_SIMILARITY) basic  build/target_generic/newrom

STATUS.md

@@ -1,7 +1,7 @@
 # New features
 
 
-Here are the features of the Open ROMs not found in the original ROMs from the 80s:
+Here are the features of the Open ROMs not found in the original ROMs from the 80s (many of them are [configurable](CONFIG.md)):
 
 * improved keyboard scanning, supports multi-key roll-over and rejection of spurious joystick input
 * joystick (port 1) can be used to move text cursor

c64/,,config_generic.s

@@ -0,0 +1,19 @@
+
+//
+// Please read CONFIG.md before modifying this file!
+//
+
+
+#define CONFIG_MEMORY_MODEL_38K
+// #define CONFIG_MEMORY_MODEL_60K
+
+// #define CONFIG_SID_2ND
+.const CONFIG_SID_2ND_ADDRESS = $D420
+
+// #define CONFIG_SID_3RD 
+.const CONFIG_SID_3RD_ADDRESS = $D440
+
+// #define CONFIG_SID_D4XX
+// #define CONFIG_SID_D5XX
+
+#define CONFIG_DOS_WEDGE

c64/,,config_mega65.s

@@ -0,0 +1,19 @@
+
+//
+// Please read CONFIG.md before modifying this file!
+//
+
+
+// #define CONFIG_MEMORY_MODEL_38K
+#define CONFIG_MEMORY_MODEL_60K
+
+#define CONFIG_SID_2ND
+.const CONFIG_SID_2ND_ADDRESS = $D420
+
+// #define CONFIG_SID_3RD
+.const CONFIG_SID_3RD_ADDRESS = $D440
+
+// #define CONFIG_SID_D4XX
+// #define CONFIG_SID_D5XX
+
+#define CONFIG_DOS_WEDGE

c64/,,config_ultimate64.s

@@ -0,0 +1,19 @@
+
+//
+// Please read CONFIG.md before modifying this file!
+//
+
+
+#define CONFIG_MEMORY_MODEL_38K
+// #define CONFIG_MEMORY_MODEL_60K
+
+// #define CONFIG_SID_2ND
+.const CONFIG_SID_2ND_ADDRESS = $D420
+
+// #define CONFIG_SID_3RD
+.const CONFIG_SID_3RD_ADDRESS = $D440
+
+#define CONFIG_SID_D4XX
+#define CONFIG_SID_D5XX
+
+#define CONFIG_DOS_WEDGE

c64/aliases/,aliases_hardware.s

@@ -10,6 +10,8 @@
 
 	// VIC-II registers
 
+	.label VIC_BASE     = $D000  // base address of the chip
+
 	.label VIC_SP0X     = $D000
 	.label VIC_SP0Y     = $D001
 	.label VIC_SP1X     = $D002
@@ -62,6 +64,8 @@
 	
 	// SID registers
 
+	.label SID_BASE     = $D400  // base address of the chip
+
 	.label SID_FRELO1   = $D400
 	.label SID_FREHI1   = $D401
 	.label SID_PWLO1    = $D402
@@ -97,6 +101,8 @@
 
 	// CIA #1 registers
 
+	.label CIA1_BASE    = $DC00  // base address of the chip
+
 	.label CIA1_PRA     = $DC00
 	.label CIA1_PRB     = $DC01
 	.label CIA1_DDRA    = $DC02
@@ -119,6 +125,8 @@
 
 	// CIA #2 registers
 
+	.label CIA2_BASE    = $DD00  // base address of the chip
+
 	.label CIA2_PRA     = $DD00  // VIC bank switching and IEC port
 	.label CIA2_PRB     = $DD01
 	.label CIA2_DDRA    = $DD02

c64/basic/,aliases.s

@@ -113,6 +113,8 @@
 	.label enable_case_switch = $0291
 	.label screen_scroll_disable = $0292
 
+#if CONFIG_MEMORY_MODEL_60K
+
 	// BASIC uses some extra bytes for memory access under ROMs located at $2A7 onwards
 	// IRQs are disabled when doing such accesses, and a default NMI handler only increments
 	// a counter, so that if an NMI occurs, it doesn't crash the machine, but can be captured.
@@ -124,3 +126,5 @@
 	.label poke_under_roms = tiny_nmi_handler+poke_under_roms_routine-tiny_nmi_handler_routine
 	.label memmap_allram = tiny_nmi_handler+memmap_allram_routine-tiny_nmi_handler_routine
 	.label memmap_normal = tiny_nmi_handler+memmap_normal_routine-tiny_nmi_handler_routine
+
+#endif // CONFIG_MEMORY_MODEL_60K

c64/basic/basic_delete_line.s

@@ -14,12 +14,24 @@ basic_delete_line:
 	// .byte $0d,0
 
 	// Get address of next line
-	ldx #<basic_current_line_ptr
 	ldy #0
+
+#if CONFIG_MEMORY_MODEL_60K
+	ldx #<basic_current_line_ptr
 	jsr peek_under_roms
+#else // CONFIG_MEMORY_MODEL_38K
+	lda (basic_current_line_ptr),y
+#endif
+
 	sta tokenise_work3
 	iny
+
+#if CONFIG_MEMORY_MODEL_60K	
 	jsr peek_under_roms
+#else // CONFIG_MEMORY_MODEL_38K
+	lda (basic_current_line_ptr),y
+#endif
+
 	sta tokenise_work4
 
 	// Work out length of this line by looking at the pointer

c64/basic/basic_execute_line.s

@@ -2,10 +2,15 @@
 // after first checking that we have a colon
 // or $00 char
 
-basic_end_of_statement_check:	
+basic_end_of_statement_check:
-	ldx #<basic_current_statement_ptr
 	ldy #0
+
+#if CONFIG_MEMORY_MODEL_60K
+	ldx #<basic_current_statement_ptr
 	jsr peek_under_roms
+#else // CONFIG_MEMORY_MODEL_38K
+	lda (basic_current_statement_ptr),y
+#endif
 
 	// Consume any spaces
 	cmp #$20
@@ -35,8 +40,14 @@ basic_execute_statement:
 !:
 	// Skip over any white space and :
 	ldy #0
+
+#if CONFIG_MEMORY_MODEL_60K
 	ldx #<basic_current_statement_ptr
 	jsr peek_under_roms
+#else // CONFIG_MEMORY_MODEL_38K
+	lda (basic_current_statement_ptr),y
+#endif
+
 	jsr basic_end_of_statement_check
 	bcs basic_end_of_line
 	
@@ -58,10 +69,17 @@ basic_execute_statement:
 	
 	// Get next char of program text, even if it is hiding under a ROM or the
 	// IO area.
-	ldx #<basic_current_statement_ptr
+
 	ldy #0
+
+#if CONFIG_MEMORY_MODEL_60K
+	ldx #<basic_current_statement_ptr
 	jsr peek_under_roms
 	cmp #$00
+#else // CONFIG_MEMORY_MODEL_38K
+	lda (basic_current_statement_ptr),y
+#endif
+
 	beq basic_end_of_line
 	
 	// The checks should be done in order of frequency, so that we are as
@@ -94,7 +112,7 @@ not_a_token:
 	cmp #$3a
 	beq basic_skip_char
 	
-// START wedge support
+#if CONFIG_DOS_WEDGE
 	
 	// Are we in direct mode?
 	// DOS Wedge is a hacky solution (inelegant, but convenient),
@@ -111,7 +129,8 @@ not_a_token:
 	jsr basic_consume_character
 	jmp wedge_dos
 !:
-// END wedge support
+
+#endif // CONFIG_DOS_WEDGE
 
 	// If all else fails, it's a syntax error
 	jmp do_SYNTAX_error
@@ -122,8 +141,14 @@ basic_skip_char:
 
 basic_fetch_and_consume_character:
 	ldy #0
+
+#if CONFIG_MEMORY_MODEL_60K
 	ldx #<basic_current_statement_ptr
 	jsr peek_under_roms
+#else // CONFIG_MEMORY_MODEL_38K
+	lda (basic_current_statement_ptr),y
+#endif
+
 	// FALL THROUGH
 	
 basic_consume_character:
@@ -179,8 +204,7 @@ basic_execute_from_current_line:
 	// Check if pointer is null, if so, we are at the end of
 	// the program.
 	ldy #0
-	ldx #<basic_current_line_ptr
+	jsr peek_line_pointer_null_check
-	jsr peek_pointer_null_check
 	bcs !+
 	// End of program reached
 	jmp basic_main_loop
@@ -194,13 +218,24 @@ basic_execute_from_current_line:
 	adc #0
 	sta basic_current_statement_ptr+1
 
-	// Store line number
-	ldx #<basic_current_line_ptr
 	ldy #2
+
+#if CONFIG_MEMORY_MODEL_60K
+	ldx #<basic_current_line_ptr
 	jsr peek_under_roms
+#else // CONFIG_MEMORY_MODEL_38K
+	lda (basic_current_line_ptr),y
+#endif
+
 	sta basic_current_line_number+0
 	iny
+
+#if CONFIG_MEMORY_MODEL_60K
 	jsr peek_under_roms
+#else // CONFIG_MEMORY_MODEL_38K
+	lda (basic_current_line_ptr),y
+#endif
+
 	sta basic_current_line_number+1
 
 	jmp basic_execute_statement

c64/basic/basic_find_line.s

@@ -13,8 +13,14 @@ basic_find_line_loop:
 	// Line number
 	
 	ldy #3
-	ldx #<basic_current_line_ptr
+
+#if CONFIG_MEMORY_MODEL_60K
+	ldx #<basic_current_line_ptr+0
 	jsr peek_under_roms
+#else // CONFIG_MEMORY_MODEL_38K
+	lda (basic_current_line_ptr),y
+#endif
+
 	cmp basic_line_number+1
 	beq !+
 	bcs line_num_too_high
@@ -22,7 +28,13 @@ basic_find_line_loop:
 !:
 	
 	dey
+
+#if CONFIG_MEMORY_MODEL_60K
 	jsr peek_under_roms
+#else // CONFIG_MEMORY_MODEL_38K
+	lda (basic_current_line_ptr),y
+#endif
+
 	cmp basic_line_number+0
 	beq !+
 	bcs line_num_too_high
@@ -32,8 +44,7 @@ basic_find_line_loop:
 	rts
 not_this_line:
 	// Not this line, so advance to next line
-	ldx #<basic_current_line_ptr
+	jsr peek_line_pointer_null_check
-	jsr peek_pointer_null_check
 	bcs more_lines_exist
 
 	// no more lines exist, return failure
@@ -46,11 +57,23 @@ more_lines_exist:
 	// if the link goes backwards.
 	// Follow link to next line
 	ldy #0
-	ldx #<basic_current_line_ptr
+
+#if CONFIG_MEMORY_MODEL_60K
+	ldx #<basic_current_line_ptr+0
 	jsr peek_under_roms
+#else // CONFIG_MEMORY_MODEL_38K
+	lda (basic_current_line_ptr),y
+#endif
+
 	sta $0100
 	iny
+
+#if CONFIG_MEMORY_MODEL_60K
 	jsr peek_under_roms
+#else // CONFIG_MEMORY_MODEL_38K
+	lda (basic_current_line_ptr),y
+#endif
+
 	sta basic_current_line_ptr+1
 	lda $0100
 	sta basic_current_line_ptr+0

c64/basic/basic_find_next_line.s

@@ -4,11 +4,23 @@
 basic_find_next_line:
 
 	ldy #0
-	ldx #<basic_current_line_ptr
+
+#if CONFIG_MEMORY_MODEL_60K
+	ldx #<basic_current_line_ptr+0
 	jsr peek_under_roms
+#else // CONFIG_MEMORY_MODEL_38K
+	lda (basic_current_line_ptr),y
+#endif
+
 	pha
 	iny
+
+#if CONFIG_MEMORY_MODEL_60K
 	jsr peek_under_roms
+#else // CONFIG_MEMORY_MODEL_38K
+	lda (basic_current_line_ptr),y
+#endif
+
 	sta basic_current_line_ptr+1
 	pla
 	sta basic_current_line_ptr+0

c64/basic/basic_follow_link_to_next_line.s

@@ -1,10 +1,22 @@
 basic_follow_link_to_next_line:
 	ldy #0
-	ldx #<basic_current_line_ptr
+
+#if CONFIG_MEMORY_MODEL_60K
+	ldx #<basic_current_line_ptr+0
 	jsr peek_under_roms
+#else // CONFIG_MEMORY_MODEL_38K
+	lda (basic_current_line_ptr),y
+#endif
+
 	pha
 	iny
+
+#if CONFIG_MEMORY_MODEL_60K
 	jsr peek_under_roms
+#else // CONFIG_MEMORY_MODEL_38K
+	lda (basic_current_line_ptr),y
+#endif
+
 	sta basic_current_line_ptr+1
 	pla
 	sta basic_current_line_ptr+0

c64/basic/basic_insert_line.s

@@ -58,12 +58,23 @@ basic_insert_line:
 
 	// Write the line number
 	ldy #2
-	ldx #<basic_current_line_ptr
 	lda basic_line_number+0
+
+#if CONFIG_MEMORY_MODEL_60K
+	ldx #<basic_current_line_ptr+0
 	jsr poke_under_roms
+#else // CONFIG_MEMORY_MODEL_38K
+	sta (basic_current_line_ptr),y
+#endif
+
 	iny
 	lda basic_line_number+1
+
+#if CONFIG_MEMORY_MODEL_60K
 	jsr poke_under_roms
+#else // CONFIG_MEMORY_MODEL_38K
+	sta (basic_current_line_ptr),y
+#endif
 
 	// Now store the line body itself
 	inc tokenise_work2
@@ -71,9 +82,15 @@ line_store_loop:
 	ldx tokenise_work1
 	lda $0200,x
 	inc tokenise_work1
-	ldx #<basic_current_line_ptr
 	iny
+
+#if CONFIG_MEMORY_MODEL_60K
+	ldx #<basic_current_line_ptr+0
 	jsr poke_under_roms
+#else // CONFIG_MEMORY_MODEL_38K
+	sta (basic_current_line_ptr),y
+#endif
+
 	lda tokenise_work1
 	cmp tokenise_work2
 	bne line_store_loop
@@ -81,4 +98,3 @@ line_store_loop:
 	
 	clc
 	rts
-	

c64/basic/basic_shift_mem_down.s

@@ -101,8 +101,7 @@ basic_shift_mem_down_and_relink:
 
 	// Check if we still have any lines left
 	ldy #0
-	ldx #<basic_current_line_ptr
+	jsr peek_line_pointer_null_check
-	jsr peek_pointer_null_check
 	bcs relink_down_next_line
 	// Nope, so just return
 	clc
@@ -115,23 +114,46 @@ relink_down_next_line:
 	
 	// Subtract tokenise_work3 from the pointer
 	ldy #0
+
+#if CONFIG_MEMORY_MODEL_60K
 	ldx #<basic_current_line_ptr+0
 	jsr peek_under_roms
+#else // CONFIG_MEMORY_MODEL_38K
+	lda (basic_current_line_ptr),y
+#endif
+
 	sec
 	sbc tokenise_work3
 	sta memmove_src+0
 	iny
+
+#if CONFIG_MEMORY_MODEL_60K
 	jsr peek_under_roms
+#else // CONFIG_MEMORY_MODEL_38K
+	lda (basic_current_line_ptr),y
+#endif
+
 	sbc #0
 	sta memmove_src+1
 
 	ldy #0
-	ldx #<basic_current_line_ptr
 	lda memmove_src+0
+
+#if CONFIG_MEMORY_MODEL_60K
+	ldx #<basic_current_line_ptr+0
 	jsr poke_under_roms
+#else // CONFIG_MEMORY_MODEL_38K
+	sta (basic_current_line_ptr),y
+#endif
+
 	iny
 	lda memmove_src+1
+
+#if CONFIG_MEMORY_MODEL_60K
 	jsr poke_under_roms
+#else // CONFIG_MEMORY_MODEL_38K
+	sta (basic_current_line_ptr),y
+#endif
 
 relink_down_loop:	
 	// Now advance pointer to the next line,
@@ -141,8 +163,7 @@ relink_down_loop:
 	sta basic_current_line_ptr+1
 
 	// Have we run out of lines to patch?
-	ldx #<basic_current_line_ptr
+	jsr peek_line_pointer_null_check
-	jsr peek_pointer_null_check
 	bcs relink_down_next_line
 
 	clc

c64/basic/basic_shift_mem_up.s

@@ -105,12 +105,24 @@ basic_shift_mem_up_and_relink:
 	// pointer to itself, so that we can add the shift
 	// to make it end up pointing to the next line
 	ldy #0
-	ldx #<basic_current_line_ptr+0
+
 	lda basic_current_line_ptr+0
+
+#if CONFIG_MEMORY_MODEL_60K
+	ldx #<basic_current_line_ptr+0
 	jsr poke_under_roms
+#else // CONFIG_MEMORY_MODEL_38K
+	sta (basic_current_line_ptr),y
+#endif
+
 	iny
 	lda basic_current_line_ptr+1
+
+#if CONFIG_MEMORY_MODEL_60K
 	jsr poke_under_roms
+#else // CONFIG_MEMORY_MODEL_38K
+	sta (basic_current_line_ptr),y
+#endif
 	
 relink_up_next_line:
 	// inc $d020
@@ -118,15 +130,28 @@ relink_up_next_line:
 	
 	// Advance pointer by tokenise_word3 bytes
 	ldy #0
+
+#if CONFIG_MEMORY_MODEL_60K
 	ldx #<basic_current_line_ptr+0
 	jsr peek_under_roms
+#else // CONFIG_MEMORY_MODEL_38K
+	lda (basic_current_line_ptr),y
+#endif
+
 	sta memmove_dst+0
 	clc
 	adc tokenise_work3
 	sta memmove_src+0
 	iny
 	php
+
+#if CONFIG_MEMORY_MODEL_60K
 	jsr peek_under_roms
+	cmp #$00
+#else // CONFIG_MEMORY_MODEL_38K
+	lda (basic_current_line_ptr),y
+#endif
+
 	sta memmove_dst+1
 	plp
 	adc #0
@@ -147,13 +172,23 @@ relink_up_next_line:
 	
 	// Write memmove_src back to current line pointer
 	ldy #0
-	ldx #<basic_current_line_ptr
 	lda memmove_src+0
+
+#if CONFIG_MEMORY_MODEL_60K
+	ldx #<basic_current_line_ptr+0
 	jsr poke_under_roms
+#else // CONFIG_MEMORY_MODEL_38K
+	sta (basic_current_line_ptr),y
+#endif
+
 	iny
 	lda memmove_src+1
-	jsr poke_under_roms
 
+#if CONFIG_MEMORY_MODEL_60K
+	jsr poke_under_roms
+#else // CONFIG_MEMORY_MODEL_38K
+	sta (basic_current_line_ptr),y
+#endif
 	
 relink_up_loop:	
 	// Now advance pointer to the next line,
@@ -163,8 +198,7 @@ relink_up_loop:
 	sta basic_current_line_ptr+1
 
 	// Have we run out of lines to patch?
-	ldx #<basic_current_line_ptr
+	jsr peek_line_pointer_null_check
-	jsr peek_pointer_null_check
 	bcs relink_up_next_line
 
 	rts

c64/basic/basic_warm_start.s

@@ -1,7 +1,11 @@
 // Clear screen etc, show READY prompt.
 
 basic_warm_start:
+
+#if CONFIG_MEMORY_MODEL_60K
+	// We need our helpers to get to filenames under ROMs or IO area
 	jsr install_ram_routines
+#endif
 
 	// If warm start caused by BRK, print it address
 	lda CMP0

c64/basic/cmd_list.s

@@ -10,10 +10,17 @@ cmd_list:
 	sta basic_current_line_ptr+1
 
 list_loop:
-	ldx #<basic_current_line_ptr
+
 	ldy #1
+
+#if CONFIG_MEMORY_MODEL_60K
+	ldx #<basic_current_line_ptr+0
 	jsr peek_under_roms
 	cmp #$00
+#else // CONFIG_MEMORY_MODEL_38K
+	lda (basic_current_line_ptr),y
+#endif
+
 	bne list_more_lines
 
 	// LIST terminates any running program,
@@ -34,10 +41,22 @@ list_more_lines:
 list_single_line: // entry point needed by DOS wedge
 	// Print line number
 	ldy #3
+
+#if CONFIG_MEMORY_MODEL_60K
 	jsr peek_under_roms
+#else // CONFIG_MEMORY_MODEL_38K
+	lda (basic_current_line_ptr),y
+#endif
+
 	pha
 	dey
+
+#if CONFIG_MEMORY_MODEL_60K
 	jsr peek_under_roms
+#else // CONFIG_MEMORY_MODEL_38K
+	lda (basic_current_line_ptr),y
+#endif
+
 	tax
 	pla
 	jsr print_integer
@@ -51,9 +70,15 @@ list_single_line: // entry point needed by DOS wedge
 	
 	ldy #4
 list_print_loop:	
+
+#if CONFIG_MEMORY_MODEL_60K
 	ldx #<basic_current_line_ptr
-	jsr peek_under_roms	
+	jsr peek_under_roms
 	cmp #$00
+#else // CONFIG_MEMORY_MODEL_38K
+	lda (basic_current_line_ptr),y
+#endif
+
 	beq list_end_of_line
 	cmp #$22
 	bne list_not_quote

c64/basic/cmd_load.s

@@ -144,9 +144,15 @@ basic_relink_program:
 basic_relink_loop:	
 	// Is the pointer to the end of the program
 	ldy #1
+
+#if CONFIG_MEMORY_MODEL_60K
 	ldx #<basic_current_line_ptr+0
 	jsr peek_under_roms
 	cmp #$00
+#else // CONFIG_MEMORY_MODEL_38K
+	lda (basic_current_line_ptr),y
+#endif
+
 	bne !+
 
 	// End of program
@@ -156,8 +162,14 @@ basic_relink_loop:
 	// Skip forward pointer and line number
 	ldy #4
 end_of_line_search:
+
+#if CONFIG_MEMORY_MODEL_60K
 	ldx #<basic_current_line_ptr+0
 	jsr peek_under_roms
+#else // CONFIG_MEMORY_MODEL_38K
+	lda (basic_current_line_ptr),y
+#endif
+
 	cmp #$00
 	beq !+
 
@@ -182,13 +194,25 @@ end_of_line_search:
 	pha
 	php
 	ldy #0
+
+#if CONFIG_MEMORY_MODEL_60K
 	ldx #<basic_current_line_ptr+0
 	jsr poke_under_roms
+#else // CONFIG_MEMORY_MODEL_38K
+	sta (basic_current_line_ptr),y
+#endif
+
 	plp
 	lda basic_current_line_ptr+1
 	adc #0
 	ldy #1
+
+#if CONFIG_MEMORY_MODEL_60K
 	jsr poke_under_roms
+#else // CONFIG_MEMORY_MODEL_38K
+	sta (basic_current_line_ptr),y
+#endif
+
 	sta basic_current_line_ptr+1
 	pla
 	sta basic_current_line_ptr+0

c64/basic/cmd_new.s

@@ -44,12 +44,25 @@ basic_do_new:
 	jsr JMEMTOP
 	cpx #$80
 	beq !+
-	lda #>$f7ff
+#if CONFIG_MEMORY_MODEL_60K
+	lda #>$F7FF
+#else // CONFIG_MEMORY_MODEL_38K
+	lda #>$9FFF
+#endif
 	.byte $2C
-!:	lda #>$7FFF
+!:	
+#if CONFIG_MEMORY_MODEL_60K
+	lda #>$F7FF
+#else // CONFIG_MEMORY_MODEL_38K
+	lda #>$9FFF
+#endif
 	sta basic_top_of_memory_ptr+1
 	sta basic_start_of_strings_ptr+1
-	lda #<$f7ff
+#if CONFIG_MEMORY_MODEL_60K
+	lda #<$F7FF
+#else // CONFIG_MEMORY_MODEL_38K
+	lda #<$9FFF
+#endif
 	sta basic_top_of_memory_ptr+0
 	sta basic_start_of_strings_ptr+0	
 	

c64/basic/peek_line_pointer_null_check.s

@@ -0,0 +1,34 @@
+// Return C=1 if a pointer in BASIC memory space is NULL, else C=0
+// X = ZP pointer to check
+
+peek_line_pointer_null_check:
+
+	ldy #$00
+
+#if CONFIG_MEMORY_MODEL_60K
+	ldx #<basic_current_line_ptr+0
+	jsr peek_under_roms
+	cmp #$00
+#else // CONFIG_MEMORY_MODEL_38K
+	lda (basic_current_line_ptr),y
+#endif
+
+	bne ptr_not_null
+	iny
+
+#if CONFIG_MEMORY_MODEL_60K
+	jsr peek_under_roms
+	cmp #$00
+#else // CONFIG_MEMORY_MODEL_38K
+	lda (basic_current_line_ptr),y
+#endif
+
+	bne ptr_not_null
+
+	// Pointer is NULL
+	clc
+	rts
+
+ptr_not_null:
+	sec
+	rts

c64/basic/peek_pointer_null_check.s

@@ -1,20 +0,0 @@
-// Return C=1 if a pointer in BASIC memory space is NULL, else C=0
-// X = ZP pointer to check
-
-peek_pointer_null_check:
-	ldy #$00
-	jsr peek_under_roms
-	cmp #$00
-	bne ptr_not_null
-	iny
-	jsr peek_under_roms
-	cmp #$00
-	bne ptr_not_null
-
-	// Pointer is NULL
-	clc
-	rts
-ptr_not_null:
-	sec
-	rts
-

c64/basic/under_rom_routines.s

@@ -4,6 +4,8 @@
 // in ,aliases.s.
 // Thus those addresses are expressed using formulae.
 
+#if CONFIG_MEMORY_MODEL_60K
+
 install_ram_routines:
 	// Copy routines into place
 	ldx #ram_routines_end-ram_routines_start-1
@@ -106,3 +108,47 @@ smd1:
 	jmp memmap_normal
 
 ram_routines_end:
+
+#else // CONFIG_MEMORY_MODEL_60K
+
+shift_mem_up:
+	// Move memmove_size bytes from memmove_src to memmove_dst,
+	// where memmove_dst > memmove_src
+	// This means we have to copy from the back end down.
+	// This routine assumes the pointers are already pointed
+	// to the end of the areas, and that Y is correctly initialised
+	// to allow the copy to begin.
+	php
+smu1:	
+	lda (memmove_src),y
+	sta (memmove_dst),y
+	dey
+	bne smu1
+	dec memmove_src+1
+	dec memmove_dst+1
+	dec memmove_size+1
+	bne smu1
+	plp
+	rts
+
+shift_mem_down:
+	// Move memmove_size bytes from memmove_src to memmove_dst,
+	// where memmove_dst > memmove_src
+	// This means we have to copy from the back end down.
+	// This routine assumes the pointers are already pointed
+	// to the end of the areas, and that Y is correctly initialised
+	// to allow the copy to begin.
+	php
+smd1:
+	lda (memmove_src),y
+	sta (memmove_dst),y
+	iny
+	bne smd1
+	inc memmove_src+1
+	inc memmove_dst+1
+	dec memmove_size+1
+	bne smd1
+	plp
+	rts
+
+#endif

c64/basic/wedge_dos.s

@@ -1,5 +1,5 @@
 
-// START wedge support
+#if CONFIG_DOS_WEDGE
 
 wedge_dos:
 
@@ -235,4 +235,4 @@ wedge_dos_setnam:
 	ldy basic_current_statement_ptr+1
 	jmp JSETNAM
 
-// END wedge support
+#endif // CONFIG_DOS_WEDGE

c64/kernal/,aliases.s

@@ -62,6 +62,8 @@
 	.label enable_case_switch = $0291
 	.label screen_scroll_disable = $0292
 
+#if CONFIG_MEMORY_MODEL_60K
+
 	// Under-ROM routines
 	// (BASIC also includes them. XXX - We should de-duplicate them in a safe manner)
 	.label missed_nmi_flag = $2A7
@@ -71,3 +73,4 @@
 	.label memmap_allram = tiny_nmi_handler+memmap_allram_routine-tiny_nmi_handler_routine
 	.label memmap_normal = tiny_nmi_handler+memmap_normal_routine-tiny_nmi_handler_routine
 
+#endif // CONFIG_MEMORY_MODEL_60K

c64/kernal/f34a.open.s

@@ -81,8 +81,10 @@ open_iec:
 	jmp kernalerror_DEVICE_NOT_FOUND
 !:
 
+#if CONFIG_MEMORY_MODEL_60K
 	// We need our helpers to get to filenames under ROMs or IO area
 	jsr install_ram_routines
+#endif
 
 	// Send command ('file name')
 	jsr lvs_send_file_name

c64/kernal/f4a5.load.s

@@ -31,8 +31,10 @@ LOAD:
 	// Reset status
 	jsr kernalstatus_reset
 
+#if CONFIG_MEMORY_MODEL_60K
 	// We need our helpers to get to filenames under ROMs or IO area
 	jsr install_ram_routines
+#endif
 
 	// Allow platform-specific routine to takeover the flow
 	TARGET_HOOK_LOAD()

c64/kernal/fda3.ioinit.s

@@ -20,23 +20,51 @@ IOINIT:
 	sta CPU_R6510
 	stx CPU_D6510
 
-	// Silence the SID chips under common addresses
+	// Silence the SID chips, depending on the configuration
 
+#if !CONFIG_SID_D4XX
+	lda SID_SIGVOL
+	and #$F0
+	sta SID_SIGVOL
+#endif // !CONFIG_SID_D4XX
+
+#if CONFIG_SID_D4XX || CONFIG_SID_D5XX
 	ldy #$00
 !:
-	// SIDs under $D4xx
+
+#if CONFIG_SID_D4XX 
 	lda SID_SIGVOL, Y
 	and #$F0
 	sta SID_SIGVOL, Y
+#endif // CONFIG_SID_D4XX
+
+#if CONFIG_SID_D5XX 
 	// SIDs under $D5xx
 	lda SID_SIGVOL + $100, Y
 	and #$F0
 	sta SID_SIGVOL + $100, Y
+#endif // CONFIG_SID_D4XX
+
 	tya
 	clc
 	adc #$20
 	tay
 	bne !-
+#endif // CONFIG_SID_D4XX || CONFIG_SID_D5XX
+
+#if CONFIG_SID_2ND
+	lda SID_SIGVOL - SID_BASE + CONFIG_SID_2ND_ADDRESS
+	and #$F0
+	sta SID_SIGVOL - SID_BASE + CONFIG_SID_2ND_ADDRESS
+#endif // CONFIG_SID_2ND
+
+#if CONFIG_SID_3RD
+	lda SID_SIGVOL - SID_BASE + CONFIG_SID_3RD_ADDRESS
+	and #$F0
+	sta SID_SIGVOL - SID_BASE + CONFIG_SID_3RD_ADDRESS
+#endif // CONFIG_SID_3RD
+
+    // Initialize CIAs
 
 	// XXX: calibrate TOD for both CIA's, see here: https://codebase64.org/doku.php?id=base:efficient_tod_initialisation
 

c64/kernal/lvs_helpers.s

@@ -8,8 +8,14 @@ lvs_send_file_name:
 lvs_send_file_name_loop:
 	cpy FNLEN
 	beq lvs_send_file_name_done
-	ldx #<current_filename_ptr
+
+#if CONFIG_MEMORY_MODEL_60K
+	ldx #<current_filename_ptr+0
 	jsr peek_under_roms
+#else // CONFIG_MEMORY_MODEL_38K
+	lda (current_filename_ptr),y
+#endif
+
 	iny
 	// Set Carry flag on the last file name character, to mark EOI
 	cpy FNLEN
@@ -73,8 +79,14 @@ lvs_display_searching_for:
 !:
 	cpy FNLEN
 	beq lvs_display_end
-	ldx #<current_filename_ptr
+
+#if CONFIG_MEMORY_MODEL_60K
+	ldx #<current_filename_ptr+0
 	jsr peek_under_roms
+#else // CONFIG_MEMORY_MODEL_38K
+	lda (current_filename_ptr),y
+#endif
+
 	jsr JCHROUT
 	iny
 	jmp !-

c64/kernal/under_rom_routines.s

@@ -4,6 +4,8 @@
 // in ,aliases.s.
 // Thus those addresses are expressed using formulae.
 
+#if CONFIG_MEMORY_MODEL_60K
+
 install_ram_routines:
 	// Copy routines into place
 	ldx #ram_routines_end-ram_routines_start-1
@@ -62,3 +64,5 @@ memmap_allram_routine:
 	rts
 
 ram_routines_end:
+
+#endif // CONFIG_MEMORY_MODEL_60K