0nera/synapseos-userspace

Purpose and Build Surface

This repository supplies SynapseOS user-space programs plus a small C runtime/library for x86_64 OS processes. Applications are built through apps/Makefile; their shared linker layout is defined in apps/apps.ld. The expected output is standalone executables copied into a SynapseOS disk image.

Process Startup and ABI Boundary

User programs enter through custom assembly startup code in synlibc/crt0.asm, which establishes the C runtime before application main. Low-level kernel interaction crosses an assembly syscall boundary in synlibc/syscall.asm, exposed to C consumers through synlibc/include/syscalls.h and higher-level wrappers in synlibc/synapi.c.

Shared Userspace Runtime

synlibc is the common static runtime linked into applications. It provides foundational memory/string and POSIX-like facilities in synlibc/mem.c, synlibc/string.c, and synlibc/posix.c; public APIs are consolidated under synlibc/include/synlibc.h. This layer isolates applications from raw kernel ABI details.

Device and Graphics Interfaces

Hardware-facing APIs are represented as library interfaces rather than per-app drivers. HID input contracts reside in synlibc/include/dev/hid.h; virtual GPU access is defined by synlibc/include/vgpu.h and implemented in synlibc/vgpu.c. Applications using input or graphics should depend on these abstractions and their underlying syscall/API layer.

Application Suite

Each program is an independent userspace executable with its own main:

• System bootstrap/init: apps/init/main.c

• Interactive command environment: apps/shell/main.c

• Minimal validation/demo programs: apps/hello/main.c, apps/tests/main.c

• System-information display: apps/synfetch/main.c

• Additional interactive/game-style applications: apps/doom/main.c, apps/tel/main.c

init is the likely process-control entry application after the OS loads userspace; the shell and other binaries are peer executables deployed under /apps.

Configuration and Deployment Flow

settings.ini is a filesystem-root configuration artifact, parsed through synlibc/ini.c and its API in synlibc/include/ini.h. Build output is generated under apps/apps-bin (via apps/Makefile) and copied into a preexisting x86_64.hdd disk image with mtools; settings are copied separately to the image root. Runtime therefore depends on the SynapseOS kernel/image providing the expected filesystem, executable loader, syscall ABI, HID, and VGPU services.

Tooling and Execution Environment

The development path uses GNU Make, GCC, NASM, and mtools; QEMU is the intended x86_64 emulator/runtime. run.sh is the repository-level execution launcher, while CI is defined in .github/workflows/ci.yml.