From 225f2c8da7aeb3a694da790fc42f99cbe23bdf82 Mon Sep 17 00:00:00 2001
From: Marvin Borner
Date: Mon, 5 Apr 2021 00:27:54 +0200
Subject: Updated README and added MMAP

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 create mode 100644 MMAP.md

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+# Memory map
+
+These tables should be irrelevant for most users/developers. You may find these interesting for finding bugs or potential exploits, though.
+
+**Note**: All memory endings in the tables are exclusive.
+
+## Available (QEMU with 256M-2G)
+
+|    Start     |     End      | Available |
+| :----------: | :----------: | :-------: |
+| `0x00000000` | `0x0009fc00` |     Y     |
+| `0x0009fc00` | `0x000a0000` |     N     |
+| `0x000f0000` | `0x00100000` |     N     |
+| `0x00100000` | `0x????????` |     Y     |
+| `0x????????` | `0x40000000` |     N     |
+| `0x40000000` | `0xffffffff` |     ?     |
+
+## Physical/virtual memory map (theoretical max values, mostly way smaller in practice)
+
+|    Start     |     End      |           Name            |
+| :----------: | :----------: | :-----------------------: |
+| `0x00000000` | `0x00000500` |         Unusable          |
+| `0x00000500` | `0x00000600` |        Memory map         |
+| `0x00007c00` | `0x00007e00` | Bootloader (first stage)  |
+| `0x00007e00` | `0x00008000` | Bootloader (second stage) |
+| `0x00009000` | `0x00009???` | Bootloader (third stage)  |
+| `0x0000c000` | `0x0008????` |      Bootloader heap      |
+| `0x00100000` | `0x001?????` |          Kernel           |
+| `0x00400000` | `0x00500000` |       Kernel stack        |
+| `0x03000000` | `0x03??????` |        VESA buffer        |
+| `0x40000000` | `0x????????` |    Userspace (virtual)    |
+
+## Notes
+
+I've designed this memory map with future expansion in mind, that's why there are some gaps in the map.
+
+All physical kernel memory ranges are identity-mapped into the virtual space.
+
+The free virtual space below the virtual userspace boundary is used for the kernel heap. The free virtual space above the virtual userspace boundary is used for the userspace programs, libraries, heap and stack.
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