preparation towardfs string concatenation

src/basic/basic_operators/oper_add.s

@@ -58,10 +58,11 @@ oper_add_strings:
 	adc __FAC2+0
 	bcs_16 do_STRING_TOO_LONG_error
 
-	// jsr alloc_temp_string
-
 .break
 
+	jsr tmpstr_alloc
+
+
 
 
 	// XXX finish the implementation

src/basic/engine/do_new_clr_restore.s

@@ -51,7 +51,7 @@ do_clr:
 
 	// See Computes Mapping the Commodore 64 - page 96
 
-	// XXX check on real ROMs that it is being done too when entering new line
+	// XXX check if original ROM does this too
 	jsr JCLALL
 
 	lda MEMSIZ+0
@@ -69,6 +69,13 @@ do_clr:
 	sta ARYTAB+1
 	sta STREND+1	
 
+	// This is a good place to reset the temporary string stack
+
+	lda #$19
+	sta TEMPPT
+	lda #$16
+	sta LASTPT
+
 	// FALLTROUGH (confirmed on real C64 that CLR indeed resets DATPTR)
 
 do_restore:

src/basic/engine/end_of_statement.s

@@ -9,6 +9,7 @@
 
 end_of_statement:
 
+	jsr tmpstr_free_all
 	jsr fetch_character_skip_spaces
 
 	cmp #$3A                           // check for colon

src/basic/engine/execute_line_statements.s

@@ -27,16 +27,7 @@ execute_statements:
 
 	// Not end of the line - it seems we actually have something to execute	
 
-	// Initialize temporary string stack - just about any statement might need it
-	// XXX original C64 ROM initializes this during the startup too - not sure where to put this
-
-	ldx #$16
-	stx LASTPT
-	ldx #$19
-	stx TEMPPT
-
 	// Move token code to .X
-
 	tax
 
 	// Push the 'end_of_statement' address for RTS

src/basic/engine/tmpstr_alloc.s

@@ -0,0 +1,21 @@
+// #LAYOUT# STD *       #TAKE
+// #LAYOUT# *   BASIC_0 #TAKE
+// #LAYOUT# *   *       #IGNORE
+
+//
+// Allocates memory for a temporary string
+//
+// Input:
+// -.A desired string length, has to be > 0
+//
+//
+
+tmpstr_alloc:
+
+	// First we need to find a free temporary string descriptor
+
+	// XXX TEMPPT-> LASTPT
+
+	// XXX implement this
+
+	rts

src/basic/engine/tmpstr_free_all.s

@@ -0,0 +1,10 @@
+// #LAYOUT# STD *       #TAKE
+// #LAYOUT# *   BASIC_0 #TAKE
+// #LAYOUT# *   *       #IGNORE
+
+
+tmpstr_free_all:
+
+	// XXX implement this
+	
+	rts

src/basic/engine/varstr_garbage_collect.s

@@ -289,6 +289,22 @@ varstr_garbage_collect_check_bptr:
 	lda __FAC1+2
 	adc INDEX+1
 	sta __FAC1+2
+!:
+	// Same for __FAC2
+
+	lda __FAC2+2
+	cmp TXTPTR+1
+	bne !+
+	lda __FAC2+1
+	cmp TXTPTR+0
+	bne !+
+
+	clc
+	adc INDEX+0
+	sta __FAC2+1
+	lda __FAC2+2
+	adc INDEX+1
+	sta __FAC2+2
 !:
 	// Next iteration