add get_opcode and its test, fix a couple bugs + semantics things

1 files changed, 14 insertions, 0 deletions

diff --git a/twasm/README.md b/twasm/README.md
index ce6beec..d6d2ec5 100644
--- a/twasm/README.md
+++ b/twasm/README.md
@@ -144,6 +144,20 @@ type metadata for the different types is as follows:
 11b ; 64 bit
 ```
 
+#### `opcodes.by_id`
+
+entries are as follows:
+
+```
++----------+--------+----------+
+| 31    24 | 23  16 | 15     0 |
++----------+--------+----------+
+| reserved | opcode | token ID |
++----------+--------+----------+
+```
+
+note the lack of support for multiple-byte opcodes or multiple opcodes for one token ID; these features will likely be added at some point after the parser accumulates too much jank.
+
 ### token IDs
 
 supported tokens are listed below