Add tan_FAC1

STATUS.md

@@ -255,7 +255,7 @@ Floating point mathematical routines - not official, but well known and broadly
 | `$E0BE`   | `rnd_generate`         | DONE     |                                                    |
 | `$E264`   | `cos_FAC1`             | PARTIAL  | needs `sin_FAC1`                                   |
 | `$E26B`   | `sin_FAC1`             | NOT DONE | some work already started                          |
-| `$E2B4`   | `tan_FAC1`             | NOT DONE |                                                    |
+| `$E2B4`   | `tan_FAC1`             | PARTIAL  | not fully tested yet                               |
 | `$E30E`   | `atn_FAC1`             | NOT DONE |                                                    |
 
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