syscalls needed for doom (tell/eof/draw_fb) + minor fixes, compiler shut up etc

docs/MANUAL.md

@@ -41,12 +41,4 @@ The recommended hardware to run PepperOS is the following:
 ## III. Syscall table
 
 The syscall interface in the Pepper kernel uses the System V ABI convention for argument order.
-It vaguely mimics Unix-like systems.
-
-Name | Number (%rax) | arg0 (%rdi) | arg1 (%rsi) | arg2 (%rdx) |
-|---|---|---|---|---|
-| sys_read | 0 | unsigned int fd | char* buf | size_t count |
-| sys_write | 1 | unsigned int fd | const char* buf | size_t count |
-| sys_open | 2 | const char* filename | int flags | |
-| sys_close | 3 | unsigned int fd | | |
-| sys_exit | 60 | int error_code | | |
+It vaguely mimics Unix-like systems. You will find it in [SYSCALLS.md](SYSCALLS.md).

docs/SOFTWARE.md

@@ -19,6 +19,8 @@ Of course, all of the freestanding headers are available:
 
 Also available is the `<syscall.h>` header that gives access to low-level system call interface, notably the `syscallX` function family, X being the amount of arguments to use.
 
+(TODO: put the other headers here once libc is more complete)
+
 ## 1. Write the source code
 
 PepperOS is able to run programs written in x86 assembly, and C programs.

docs/SYSCALLS.md

@@ -0,0 +1,11 @@
+# Pepper kernel system call table
+
+The following table contains all of the system calls supported by PepperOS, as well as their arguments. The explanation for what every system call does is available as a comment above each function in corresponding files in the `src/syscall` folder.
+
+Name | Number (%rax) | arg0 (%rdi) | arg1 (%rsi) | arg2 (%rdx) |
+|---|---|---|---|---|
+| sys_read | 0 | unsigned int fd | char* buf | size_t count |
+| sys_write | 1 | unsigned int fd | const char* buf | size_t count |
+| sys_open | 2 | const char* filename | int flags | |
+| sys_close | 3 | unsigned int fd | | |
+| sys_exit | 60 | int error_code | | |