Add some XV6 notes

Notes/XV6/XV6FileSystem.md

@@ -0,0 +1,21 @@
+# XV6 Source Code Reading -- File System
+
+## Requirement
+
+Code to read
+
+* File system
+  * [ ] `buf.h` (p.38)
+  * [ ] `sleeplock.h` (p.39)
+  * [ ] `fcntl.h` (p.39)
+  * [ ] `stat.h` (p.40)
+  * [ ] `fs.h` (p.40)
+  * [ ] `file.h` (p.41)
+  * [ ] `ide.c` (p.42)
+  * [ ] `bio.c` (p.44)
+  * [ ] `sleeplock.c` (p.46)
+  * [ ] `log.c` (p.47)
+  * [ ] `fs.c` (p.49)
+  * [ ] `file.c` (p.58)
+  * [ ] `sysfile.c` (p.60)
+  * [ ] `exec.c` (p.66)

Notes/XV6/XV6InterruptSyscall.md

@@ -0,0 +1,36 @@
+# XV6 Source Code Reading -- Interrupt and System Call
+
+## Requirement
+
+Code to read
+
+* Bootloader
+  * [ ] `bootasm.S` (p.91)
+  * [ ] `bootmain.c` (p.92)
+* Entering xv6
+  * [ ] `entry.S` (p.10)
+  * [ ] `entryother.S` (p.11)
+  * [ ] `main.c` (p.12)
+* System calls (and interrupt)
+  * [ ] `traps.h` (p.32)
+  * [ ] `vectors.pl` (p.32)
+  * [ ] `trapasm.S` (p.33)
+  * [ ] `trap.c` (p.33)
+  * [ ] `syscall.h` (p.35)
+  * [ ] `syscall.c` (p.35)
+  * [ ] `sysproc.c` (p.37)
+
+## Resources
+
+### Instruction
+
+#### Interrupt
+
+* cli - Clear Interrupt Flag
+  * [x86 Instruction Set Reference - CLI](https://c9x.me/x86/html/file_module_x86_id_31.html)
+  * [CLI — Clear Interrupt Flag](https://www.felixcloutier.com/x86/cli)
+* sti - Set Interrupt Flag
+  * [STI — Set Interrupt Flag](https://www.felixcloutier.com/x86/sti)
+* int
+  * [INT n/INTO/INT3/INT1 — Call to Interrupt Procedure](https://www.felixcloutier.com/x86/intn:into:int3:int1)
+  * [wiki - INT (x86 instruction)](https://en.wikipedia.org/wiki/INT_(x86_instruction))

Notes/XV6/XV6Memory.md

@@ -0,0 +1,8 @@
+# XV6 Source Code Reading -- Memory
+
+## Requirement
+
+Code to read
+
+* [ ] `kalloc.c` (p.31)
+* [ ] `vm.c` (p.17)

Notes/XV6/XV6Synchronization.md

@@ -0,0 +1,25 @@
+# XV6 Source Code Reading -- Synchronization
+
+## Requirement
+
+Code to read
+
+* Locks
+  * [ ] `spinlock.h` (p.15)
+  * [ ] `spinlock.c` (p.15)
+
+## Resources
+
+xchg
+
+* [XCHG — Exchange Register/Memory with Register](https://www.felixcloutier.com/x86/xchg)
+* [X86組合語言/基本指令集/IA32指令:xchg](https://zh.wikibooks.org/zh-tw/X86%E7%B5%84%E5%90%88%E8%AA%9E%E8%A8%80/%E5%9F%BA%E6%9C%AC%E6%8C%87%E4%BB%A4%E9%9B%86/IA32%E6%8C%87%E4%BB%A4:xchg)
+
+### Implementation
+
+implement semaphore using spinlock
+
+implement readers-writer lock using spinlock
+
+* [Readers–writer lock - Implementation](https://en.wikipedia.org/wiki/Readers%E2%80%93writer_lock#Implementation)
+* [How would you implement your own reader/writer lock in C++11?](https://stackoverflow.com/questions/12033188/how-would-you-implement-your-own-reader-writer-lock-in-c11)

README.md

@@ -24,10 +24,10 @@ PKU OS course project and notes based on Nachos and XV6.
 ### XV6 Source Code Reading
 
 1. [Process and Thread (with Scheduling)](Notes/XV6/XV6ProcessThread.md)
-2. Synchronization Mechanism
-3. Interrupt and System Call
-4. Memory Management
-5. File System
+2. [Synchronization Mechanism](Notes/XV6/XV6Synchronization.md)
+3. [Interrupt and System Call](Notes/XV6/XV6InterruptSyscall.md)
+4. [Memory Management](Notes/XV6/XV6Memory.md)
+5. [File System](Notes/XV6/XV6FileSystem.md)
 
 ### Additional Task