work on getting BASIC line number entry working.

c64/basic/,aliases.s

@@ -6,6 +6,7 @@
 	.alias tokenise_work2 $8
 	.alias tokenise_work3 $B
 	.alias tokenise_work4 $F
+	.alias basic_line_number $14
 	.alias temp_string_ptr $35
 	.alias load_or_verify_or_tokenise_work5 $C
 	.alias basic_work22 $22
@@ -13,6 +14,18 @@
 	.alias basic_work24 $24
 	.alias basic_work25 $25
 
+	;; The various pointers that separate memory regions for BASIC storage
+	;; We have multiple names for the ones that mark the boundary of regions.
+	.alias basic_start_of_text_ptr $2b
+	.alias basic_end_of_text_ptr $2d
+	.alias basic_start_of_vars_ptr $2d
+	.alias basic_end_of_vars_ptr $2f
+	.alias basic_start_of_arrays_ptr $2f
+	.alias basic_end_of_arrays_ptr $31
+	.alias basic_start_of_free_space_ptr $31
+	.alias basic_start_of_strings_ptr $33
+	.alias basic_top_of_memory_ptr $35
+	
 	.alias basic_numeric_work_area $57 ; $57 - $60 inclusive = 10 bytes
 
 	;; Floating point accumulator 1 $61 - $68

c64/basic/basic_cold_start.s

@@ -15,6 +15,8 @@ basic_cold_start:
 	ldx #34
 	jsr print_packed_message
 
+	jsr basic_do_new
+	
 	;; jump into warm start loop
 	jmp basic_warm_start
 	

c64/basic/basic_main_loop.s

@@ -4,9 +4,13 @@ basic_main_loop:
 	;; the appropriate way.
 	;; XXX - For now, it is hard coded to direct mode
 
+	;; Tell user we are ready
+	jsr ready_message
+	
 	;; Read a line of input
 	ldx #$00
 read_line_loop:
+
 	jsr $ffcf 		; KERNAL CHRIN
 	bcs read_line_loop
 	
@@ -74,9 +78,32 @@ rsl_l1:	lda $0200,x
 	lda tokenise_work1
 	sta $0427
 
+	;; Check if the number is a valid line number
+	;; i.e., 16 bits, no exponent, no decimal
+	lda basic_fac1_mantissa+2
+	ora basic_fac1_mantissa+3
+	ora basic_fac1_exponent
+	beq +
+ml_bad_line_number:	
+	;; Syntax error
+	ldx #10
+	jmp do_basic_error
+*	lda tokenise_work4
+	cmp #$ff
+	beq ml_bad_line_number
+
+	;; Got a valid line number.
+
+	;; Copy to line number holder
+	lda basic_fac1_mantissa+0
+	sta basic_line_number+0
+	lda basic_fac1_mantissa+1
+	sta basic_line_number+1
+
+	;; Delete line if present
+
+	;; Insert new line if non-zero length
 	
 not_a_line:	
 	
-	jsr ready_message
-
 	jmp basic_main_loop

c64/basic/basic_warm_start.s

@@ -1,6 +1,5 @@
 	;; Clear screen etc, show READY prompt.
 
 basic_warm_start:
-	jsr ready_message
 	jmp basic_main_loop
 	

c64/basic/cmd_new.s

@@ -0,0 +1,33 @@
+
+cmd_new:
+	jsr basic_do_new
+	jmp basic_main_loop
+
+cmd_clr:
+	jsr basic_do_clr
+	jmp basic_main_loop
+	
+basic_do_new:	
+	;; Setup pointers to memory storage
+	lda #<$0801
+	sta basic_start_of_text_ptr+0
+	lda >$0801
+	sta basic_start_of_text_ptr+1
+	sta basic_start_of_vars_ptr+1
+	lda #<$0803
+	sta basic_start_of_vars_ptr+0
+
+	;; FALL THROUGH
+	
+basic_do_clr:
+	;; Clear variables, arrays and strings
+	lda basic_start_of_vars_ptr+0
+	sta basic_start_of_arrays_ptr+0
+	sta basic_start_of_free_space_ptr+0
+	lda basic_start_of_vars_ptr+1
+	sta basic_start_of_arrays_ptr+1
+	sta basic_start_of_free_space_ptr+1
+
+	rts
+	
+	

c64/basic/do_basic_error.s

@@ -4,6 +4,8 @@ do_basic_error:
 	;; "?"
 	txa
 	pha
+	lda #$0d
+	jsr $ffd2
 	lda #$3f
 	jsr $ffd2
 	pla
@@ -12,6 +14,7 @@ do_basic_error:
 	;; Error message text
 	jsr print_packed_message
 
+	;; A space between error name and word error
 	lda #$20
 	jsr $ffd2
 	

c64/basic/fac1_mul.s

@@ -52,7 +52,7 @@ f1m10_l3:
 	;; All done, return
 	clc
 	rts
-
+*
 	;; Divide mantissa by two, and increment exponent
 	jsr fac1_mantissa_div2
 	inc basic_fac1_exponent

c64/basic/injest_number.s

@@ -6,8 +6,38 @@
 	;; after to produce normalised floating point number.
 
 ij_not_a_digit:
-	;; XXX check for ".", "E", "+" and "-"
+	;; XXX check for "." or "E"
 	;; Other chars terminate the accumulation.
+
+	;; Look for exponentiation marker
+	;; XXX - Implement me!
+	;; Probably should have a flag so that we know if we are accumulating
+	;; exponent or mantissa digits
+	
+	;; Look for decimal point
+	sta $0420
+	cmp #$2e
+	bne ij_not_decimal
+	lda tokenise_work4
+	cmp #$ff
+	beq ij_found_decimal
+	;; More than one decimal point in a number means we have reached the end of the number
+	clc
+	rts
+	
+ij_found_decimal:
+	;; Found decimal.
+	;; Thus start counting digits after the decimal, so that we
+	;; can do the necessary number of divide by 10s on the final
+	;; number.
+	lda #$00
+	sta tokenise_work4
+
+	jmp ij_consider_next_digit
+	
+ij_not_decimal:
+
+	
 	CLC
 	RTS
 	
@@ -22,6 +52,17 @@ injest_number:
 	;; Check if leading char is a - sign
 	;; Note: the - will have been tokenised to $AB
 	;; XXX - implement
+	ldx tokenise_work1
+	lda $0200,x
+	cmp #$AB
+	bne ij_not_minus
+
+	;; Set sign to negative
+	lda #$ff
+	sta basic_fac1_sign
+	
+ij_not_minus:	
+
 	
 ij_loop1:	
 	ldx tokenise_work1