Add new notes, fix minor issues

notes/lua.md

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+# Lua Programming Language
+
+## Lua 5.4 C API
+
+
+## Lua 5.4 Bytecode
+
+> [!note]
+> These are **unstable** and may differ in different versions of the language.
+> They are not part of the language specification but an implementation detail, which in this case is the reference implementation.
+
+> [!note]
+> The reference implementation used to have a stack based but now uses a register based VM similar to how modern real computer architectures.
+
+The instructions are 32 bits wide; every instruction has an opcode that takes up 7 bits, which leaves out 25 bits for the addresses and values.
+
+The instructions work with three register referred to as: A, B, C; each are of length 8 bits.
+
+<table>
+<thead>
+<tr>
+<th></th>
+<th>31</th><th>...</th><th>24</th><th>23</th><th>...</th><th>16</th><th>15</th><th>14</th><th>...</th><th>7</th><th>6</th><th>...</th><th>0</th>
+</tr>
+</thead>
+<tr>
+<td>iABC</td>
+<td colspan='3' style='text-align:center'>C (8 bits)</td>
+<td colspan='3' style='text-align:center'>B (8 bits)</td>
+<td style='text-align:center'>k (1 bit)</td>
+<td colspan='3' style='text-align:center'>A (8 bits)</td>
+<td colspan='3' style='text-align:center'>OP (7 bits)</td>
+</tr>
+<tr>
+<td>iABx</td>
+<td colspan='7' style='text-align:center'>B (17 bits)</td>
+<td colspan='3' style='text-align:center'>A (8 bits)</td>
+<td colspan='3' style='text-align:center'>OP (7 bits)</td>
+</tr>
+<tr>
+<td>iAsBx</td>
+<td colspan='7' style='text-align:center'>signed B 17 bits)</td>
+<td colspan='3' style='text-align:center'>A (8 bits)</td>
+<td colspan='3' style='text-align:center'>OP (7 bits)</td>
+</tr>
+<tr>
+<td>iAx</td>
+<td colspan='10' style='text-align:center'>Ax (25 bits)</td>
+<td colspan='3' style='text-align:center'>OP (7 bits)</td>
+</tr>
+<tr>
+<td>sJ</td>
+<td colspan='10' style='text-align:center'>signed jump address (25 bits)</td>
+<td colspan='3' style='text-align:center'>OP (7 bits)</td>
+</tr>
+</table>
+
+```lua
+-- arithmetic to calculate the lengths used from https://www.lua.org/source/5.4/lopcodes.h.html
+A = 8
+B = 8
+C = 8
+Bx = A + B + 1  -- 17
+Ax = A + Bx     -- 25
+sJ = A + Bx     -- 25
+```
+This page contains excerpts from Lua's source code which is the copyright of Lua.org, PUC-Rio and is licensed under the MIT License.
+[lua.org/license.html](https://www.lua.org/license.html)