variable support cleanup

src/basic/engine_variables/fetch_variable_TI_string.s

@@ -0,0 +1,95 @@
+// #LAYOUT# STD *       #TAKE
+// #LAYOUT# *   BASIC_0 #TAKE
+// #LAYOUT# *   *       #IGNORE
+
+
+// XXX does not fully work
+
+fetch_variable_TI_string:
+
+	// Alocate memory for 6-byte temporary string, copy the string descriptor
+
+	lda #$06
+	jsr tmpstr_alloc
+	jsr helper_strdesccpy
+
+	// Fetch the time in a safe way, store it in temporary area
+
+	jsr JRDTIM
+
+	sty INDEX+0
+	stx INDEX+1
+	sta INDEX+2
+
+	// Now calculate the digits, starting from the most important one
+
+#if CONFIG_MEMORY_MODEL_60K
+	ldx #<DSCPNT+1
+#endif
+
+	ldy #$00
+
+	// FALLTROUGH
+
+fetch_variable_TI_string_loop:
+
+	// Set the initial digit value ('0')
+
+	lda #$30
+	sta INDEX+3
+
+	// Compare the counter with value from table
+!:
+	lda INDEX+2
+	cmp table_TI_hi, y
+	bcc fetch_variable_TI_string_got_digit
+	bne fetch_variable_TI_string_inc_digit
+	lda INDEX+1
+	cmp table_TI_mid, y
+	bcc fetch_variable_TI_string_got_digit
+	bne fetch_variable_TI_string_inc_digit
+	lda INDEX+0
+	cmp table_TI_lo, y
+	bcc fetch_variable_TI_string_got_digit
+
+fetch_variable_TI_string_inc_digit:
+
+	// Increment digit and subtract the table value from the counter
+
+	inc INDEX+3
+
+	sec
+	lda INDEX+0
+	sbc table_TI_lo, y
+	sta INDEX+0
+	lda INDEX+1
+	sbc table_TI_mid, y
+	sta INDEX+1
+	lda INDEX+2
+	sbc table_TI_hi, y
+	sta INDEX+2
+
+	bcs !-                   // branch always
+
+fetch_variable_TI_string_got_digit:
+
+	// Copy digit to the string
+
+	lda INDEX+3
+
+#if CONFIG_MEMORY_MODEL_60K
+	jsr poke_under_roms
+#else // CONFIG_MEMORY_MODEL_38K || CONFIG_MEMORY_MODEL_50K || CONFIG_MEMORY_MODEL_60K
+	sta (DSCPNT+1), y
+#endif
+
+	// Next iteration
+
+	iny
+	cpy #$06
+	bne fetch_variable_TI_string_loop
+
+	// Return success
+
+	clc
+	rts