several features are now optional, added legacy BASIC memory model

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:	
-	ldx #<basic_current_statement_ptr
+basic_end_of_statement_check:
 	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_pointer_null_check
+	jsr peek_line_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_pointer_null_check
+	jsr peek_line_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_pointer_null_check
+	jsr peek_line_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_pointer_null_check
+	jsr peek_line_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_pointer_null_check
+	jsr peek_line_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