tools/tms34010-sdk: the two dis34 bugs are fixed (af7d3565a5) -- record it, with the 2623/6235-line scale of the correction

tools/tms34010-sdk/README.md

@@ -61,8 +61,14 @@ fallback**, and `DOSBOX.md` documents its verified headless invocation.
 
 ## Traps worth knowing
 
-* **`dis34` prints long relative branches as `JA`** and **hides the B-file `SP`** —
-  correctness bugs in our disassembler, not in the assembler.
+* **`dis34` misreported two encodings** — long relative branches as `JA` and the
+  B-file `SP` as plain `sp`. **Both fixed** (`af7d3565a502`): `0x00` + a 16-bit
+  displacement is `JRcc` (2 words), only `0x80` + a 32-bit address is `JAcc` (3
+  words), and register field `0x1F` is `b15`. The round-trip fixup list dropped
+  from **5 to 3** as a result. For scale: the correction changes **2623** ROM
+  lines for `sp`→`b15` and **6235** for `JA`→`JR`, so disassembly read before
+  that date may have misreported those branches. The proof is reproducible —
+  the harness is committed at `harness/sdk-roundtrip/`.
 * **`gsprom`'s hex addresses wrap at 64 KB** — use the COFF file or the map for
   placement.
 * **GSPA's `MOVI` auto-shortening can silently change sign extension.**