diff --git a/preserves.md b/preserves.md
index 6850060..23dc215 100644
--- a/preserves.md
+++ b/preserves.md
@@ -1049,5 +1049,23 @@ Then, if `ttnn`=`0001`, `l` is the placeholder number; otherwise, `l`
 is the length of the body that follows, counted in bytes for `tt`=`01`
 and in `Repr`s for `tt`=`10`.
 
+## Appendix. Binary SignedInteger representation
+
+Languages that provide fixed-width machine word types may find the
+following table useful in encoding and decoding binary `SignedInteger`
+values.
+
+| Integer range                                  | Bytes required | Encoding (hex)                               |
+| ---                                            | ---            | ---                                          |
+| -3 ≤ n < 13 (numbers -3..12 encoded specially) | 1              | `3X`                                         |
+| -2<sup>7</sup> ≤ n < 2<sup>7</sup> (i8)        | 2              | `41` `XX`                                    |
+| -2<sup>15</sup> ≤ n < 2<sup>15</sup> (i16)     | 3              | `42` `XX` `XX`                               |
+| -2<sup>23</sup> ≤ n < 2<sup>23</sup> (i24)     | 4              | `43` `XX` `XX` `XX`                          |
+| -2<sup>31</sup> ≤ n < 2<sup>31</sup> (i32)     | 5              | `44` `XX` `XX` `XX` `XX`                     |
+| -2<sup>39</sup> ≤ n < 2<sup>39</sup> (i40)     | 6              | `45` `XX` `XX` `XX` `XX` `XX`                |
+| -2<sup>47</sup> ≤ n < 2<sup>47</sup> (i48)     | 7              | `46` `XX` `XX` `XX` `XX` `XX` `XX`           |
+| -2<sup>55</sup> ≤ n < 2<sup>55</sup> (i56)     | 8              | `47` `XX` `XX` `XX` `XX` `XX` `XX` `XX`      |
+| -2<sup>63</sup> ≤ n < 2<sup>63</sup> (i64)     | 9              | `48` `XX` `XX` `XX` `XX` `XX` `XX` `XX` `XX` |
+
 <!-- Heading to visually offset the footnotes from the main document: -->
 ## Notes