From 64b9d0ceff99afe85cc16740940574758aea61f1 Mon Sep 17 00:00:00 2001
From: Mario Romero <mario@1159.cl>
Date: Tue, 6 Jun 2023 16:28:22 +0000
Subject: [PATCH] Update 'ALU'

---
 ALU.md | 45 +++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 43 insertions(+), 2 deletions(-)

diff --git a/ALU.md b/ALU.md
index 4037cc4..c404af9 100644
--- a/ALU.md
+++ b/ALU.md
@@ -1,2 +1,43 @@
-# Alu
-![](https://git.1159.cl/Mario1159/RVSCC/media/branch/main/docs/figures/build/alu.svg)
+# Arithmetic Logic Unit (ALU)
+> *Defined in [rtl/alu.sv](https://git.1159.cl/Mario1159/RVSCC/src/branch/main/rtl/alu.sv)*
+
+<table>
+    <tr>
+        <th>Figure</th>
+        <th>Direction</th>
+        <th>Signal</th>
+    </tr>
+    <tr>
+        <td rowspan="5"><img src="https://git.1159.cl/Mario1159/RVSCC/media/branch/main/docs/figures/build/alu.svg"/></td>
+        <td rowspan="3">Input</td>
+        <td>a</td>
+    </tr>
+    <tr>
+        <td>b</td>
+    </tr>
+    <tr>
+        <td>operation</td>
+    </tr>
+    <tr>
+        <td rowspan="2">Output</td>
+        <td>result</td>
+    </tr>
+    <tr>
+        <td>status</td>
+    </tr>
+</table>​
+
+The Arithmetic Logic Unit (ALU) is the combinatorial circuit in charge to perform the binary operation selected by the `operation` signal.
+
+`alu_opcode_t` is the enum that represent the operations, these are defined in [rv32i_defs.sv](https://git.1159.cl/Mario1159/RVSCC/src/branch/main/rtl/rv32i_defs.sv).
+
+The `status` bus represent the following flags:
+
+
+| Bit index | Flag     | Description        |
+| --------- | -------- | ------------------ |
+| 0         | N        | Result is negative |
+| 1         | Z        | Result is zero     |
+| 2         | C        | Carry out          |
+| 3         | V        | Overflow           |
+