implemented NORMAL math routine, added more stubs

c64/basic/,stubs_math/bcf3.FIN.s

@@ -0,0 +1,23 @@
+// #LAYOUT# STD *       #TAKE
+// #LAYOUT# *   BASIC_0 #TAKE
+// #LAYOUT# *   *       #IGNORE
+
+//
+// Math package - imports string to FAC1, ignores spaces
+//
+//
+// Input:
+// - .A needs to be loaded with first char of the string
+// - Carry flag must be clear
+// - string address in $7A/$7B
+//
+// See also:
+// - [CM64] Computes Mapping the Commodore 64 - page 116
+// - https://www.c64-wiki.com/wiki/Floating_point_arithmetic
+// - https://codebase64.org/doku.php?id=base:kernal_floating_point_mathematics
+//
+
+// XXX provide implementation
+
+FIN:
+	STUB_IMPLEMENTATION()