Add FINLOG

src/basic/math/FIN.s

@@ -50,11 +50,8 @@ FIN_loop:
     sbc #48             ; Convert to number
     sta FIN_DIGIT
     jsr mul10_FAC1
-    jsr mov_FAC1_FAC2
     lda FIN_DIGIT
-    jsr convert_A_to_FAC1
-    jsr add_FAC2_FAC1
-
+    jsr FINLOG
     lda FIN_DECFOUND    ; Have we passed the decimal sign?
     bpl FIN_next
     inc FIN_NUMDEC

src/basic/math/bd7e.FINLOG.s

@@ -0,0 +1,19 @@
+;; #LAYOUT# STD *       #TAKE
+;; #LAYOUT# X16 BASIC_0 #TAKE-OFFSET 2000
+;; #LAYOUT# *   BASIC_0 #TAKE
+;; #LAYOUT# *   *       #IGNORE
+
+;
+; Math package - add an ASCII digit in A that has been converted to a signed integer to FAC1
+;
+; See also:
+; - [CM64] Computes Mapping the Commodore 64 - page 113
+;
+
+FINLOG:
+    pha
+    jsr mov_FAC1_FAC2
+    pla
+    jsr convert_A_to_FAC1
+    jsr add_FAC2_FAC1
+    rts

src/basic/math/bd7e.interop

@@ -0,0 +1,3 @@
+This is an important floating point math routine, documented in many places.
+
+XXX - try to find real-life example