variable support cleanup

src/basic/engine_variables/tmpstr_free.s

@@ -0,0 +1,97 @@
+// #LAYOUT# STD *       #TAKE
+// #LAYOUT# *   BASIC_0 #TAKE
+// #LAYOUT# *   *       #IGNORE
+
+//
+// Frees the string if it belongs to temporary string stack
+//
+// Input:
+// - DSCPNT+1/+2 - pointer to string (depending on the call addres, can fetch from FAC1/FAC2)
+//
+
+
+tmpstr_free_FAC1:
+
+	lda __FAC1+1
+	sta DSCPNT+1
+	lda __FAC1+2
+
+#if HAS_OPCODES_65C02
+	bra !+
+#else
+	jmp !+
+#endif
+
+tmpstr_free_FAC2:
+
+	lda __FAC2+1
+	sta DSCPNT+1
+	lda __FAC2+2
+!:
+	sta DSCPNT+2
+
+	// FALLTROUGH
+
+tmpstr_free:
+
+	// First find the descriptor matching the given string
+
+	ldx #$19
+
+	//FALLTROUGH
+
+tmpstr_free_loop:
+
+	cpx TEMPPT
+	bne !+
+	rts                                // quit if not found
+!:
+	// First fetch the string size - if 0, do not even try to compare
+
+	ldy $00, x
+	beq tmpstr_free_next_3
+
+	// Check if current string
+	
+	inx
+	lda $00, x
+	cmp DSCPNT+1
+	bne tmpstr_free_next_2
+
+	inx
+	lda $00, x
+	cmp DSCPNT+2
+	bne tmpstr_free_next_1
+
+	// This is the string we need to free
+
+	sty DSCPNT+0
+	phx_trash_a
+	jsr varstr_free
+	plx_trash_a
+
+	// Mark empty string as free and quit
+
+	dex
+	dex
+	lda #$00
+	sta $00, x
+
+	rts
+
+tmpstr_free_next_3:
+
+	inx
+
+	// FALLTROUGH
+
+tmpstr_free_next_2:
+
+	inx
+
+	// FALLTROUGH
+
+tmpstr_free_next_1:
+
+	inx
+	bne tmpstr_free_loop