---
title: "Sysabi"
summary: The noxos `Application Binary Interface`.
date: 2023-03-14T21:00:40+01:00
---

# Syscalls
Syscalls are a way for programms to communicate with the kernel.

To perform a syscall, you need to populate the following registers:

| Register | Value           |
|----------|-----------------|
| rax      | The syscalls ID |
| rdi      | Argument 1      |
| rsi      | Argument 2      |
| rdx      | Argument 3      |
| rcx      | Argument 4      |

The following calls should be included to some degree in NoxOS 1.0.

## Categories
### Files
| ID     | Name         | Description | Arg1 | Arg2   | Arg3 | Arg4 | Result     | Status | 
|--------|--------------|-------------|------|--------|------|------|------------|--------|
| 0x0101 | `nx_fopen`   |             | path | len    |      |      | fd         | N/A    |
| 0x0102 | `nx_fclose`  |             | fd   |        |      |      | success    | N/A    |
| 0x0103 | `nx_fread`   |             | fd   | offset | mem  | n    | num_bytes  | N/A    |
| 0x0104 | `nx_fwrite`  |             | fd   | offset | mem  | n    | num_bytes  | N/A    |
| 0x0105 | `nx_fdelete` |             | fd   |        |      |      | success    | N/A    |
| 0x0106 | `nx_flist`   |             | fd   | mem    |      |      | needed_mem | N/A    |
| 0x0107 | `nx_finfo`   |             | fd   | attr   | mem  |      | len        | N/A    |

### Memory
| Category | ID  | Name | Description | Arg1 | Arg2 | Arg3 | Arg4 | Result | Status | 
|----------|-----|------|-------------|------|------|------|------|--------|--------|
|          |     |      |             |      |      |      |      |        |        |

### Processes
| Category | ID  | Name | Description | Arg1 | Arg2 | Arg3 | Arg4 | Result | Status | 
|----------|-----|------|-------------|------|------|------|------|--------|--------|
|          |     |      |             |      |      |      |      |        |        |

### Runtime / Dynamic Linker
| Category | ID  | Name | Description | Arg1 | Arg2 | Arg3 | Arg4 | Result | Status | 
|----------|-----|------|-------------|------|------|------|------|--------|--------|
|          |     |      |             |      |      |      |      |        |        |

### Compatibility & Safety
| Category | ID  | Name | Description | Arg1 | Arg2 | Arg3 | Arg4 | Result | Status | 
|----------|-----|------|-------------|------|------|------|------|--------|--------|
|          |     |      |             |      |      |      |      |        |        |

### Kernel
The kernel syscalls can only be called from the kernels main process [link to processing article needed].
If another process calls them, they will just return without doing anything.


| Category | ID  | Name | Description | Arg1 | Arg2 | Arg3 | Arg4 | Result | Status |
|----------|-----|------|-------------|------|------|------|------|--------|--------|
|	   |     |      |             |      |      |      |      |        |        |