set end of loaded memory pointer in BASIC LOAD routine. Other small fixes.

c64/basic/cmd_load.s

@@ -0,0 +1,49 @@
+cmd_load:
+
+	;; Parse filename
+	;; (we can tell the KERNAL where it is in memory directly, since the
+	;; KERNAL will be able to peek under ROMs to read it, since it will have
+	;; to be able to peek under the ROMs for SAVE and VERIFY).
+	;; Parse optional device #
+	;; Parse optional secondary address
+	
+	;; XXX - C64 BASIC apparently doesn't clear variables after a LOAD in the
+	;; middle of a program. For safety, we do.
+	jsr basic_do_clr
+	
+	;; Try to load an IEC file
+	lda #0			; use supplied load address, not the one from the file
+	sta current_secondary_address
+	lda #$00 		; LOAD not verify
+	ldx #<$0801		; LOAD address = $0801
+	ldy #>$0801
+	jsr $ffd5
+	bcc +
+
+	;; A = KERNAL error code, which also almost match
+	;; basic ERROR codes, so we can just copy the
+	;; error code to X, decrement, and handle normally
+	tax
+	dex
+	jmp do_basic_error
+	
+*
+	;; $YYXX is the last loaded address, so store it
+	stx basic_end_of_text_ptr+0
+	sty basic_end_of_text_ptr+1
+
+	;; Now relink the loaded program, as we cannot trust the line
+	;; links supplied. For example, the VICE virtual drive emulation
+	;; always supplies $0101 as the address of the next line.
+	
+	;; After LOADing, we either start the program from the beginning,
+	;; or go back to the READY prompt if LOAD was called from direct mode.
+
+	;; Reset to start of program
+	lda basic_start_of_text_ptr+0
+	sta basic_current_line_ptr+0
+	lda basic_start_of_text_ptr+1
+	sta basic_current_line_ptr+1
+
+	;; Try to keep executing
+	jmp basic_execute_statement