implement SYS command.

c64/basic/,aliases.s

@@ -126,6 +126,12 @@
 	.alias screen_scroll_disable $0292
 	.alias pal_or_ntsc $02A6
 
+	;; Registers for SYS call
+	.alias sys_reg_a $30c
+	.alias sys_reg_x $30d
+	.alias sys_reg_y $30e
+	.alias sys_reg_p $30f
+	.alias sys_jmp   $310
 
 	;; 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

c64/basic/cmd_sys.s

@@ -0,0 +1,32 @@
+cmd_sys:
+	
+	jsr basic_end_of_statement_check
+	bcc +
+
+	;; SYS requires an argument
+	ldx #10
+	jmp do_basic_error
+	
+*
+	jsr basic_parse_line_number
+
+	;; setup call
+	lda #$4c 		;JMP
+	sta sys_jmp
+	lda basic_line_number+0
+	sta sys_jmp+1
+	lda basic_line_number+1
+	sta sys_jmp+2
+	
+	;; Setup the register values
+	lda sys_reg_p
+	pha
+	lda sys_reg_a
+	ldx sys_reg_x
+	ldy sys_reg_y
+	plp
+
+	;; Call the routine.
+	jsr sys_jmp
+	
+	jmp basic_run_next_statement

c64/basic/cmd_unimplemented.s

@@ -29,7 +29,6 @@ cmd_printhash:
 cmd_print:
 cmd_cont:
 cmd_cmd:
-cmd_sys:
 cmd_open:
 	
 	;; $A0-$AF

c64/basic/injest_number.s

@@ -59,6 +59,9 @@ injest_number:
 	;; Set sign to negative
 	lda #$ff
 	sta basic_fac1_sign
+
+	;; Skip over the minus sign
+	jsr basic_consume_character
 	
 ij_not_minus:	
 
@@ -68,7 +71,7 @@ ij_loop1:
 	lda (basic_current_statement_ptr),y
 	cmp #$30
 	bcc ij_not_a_digit
-	cmp #$39
+	cmp #$3a
 	bcs ij_not_a_digit
 
 	;; It is a digit