Docs: Added minimal build instruction

Signed-off-by: Maxim Logaev <maxlogaev@proton.me>

.gitignore

@@ -36,3 +36,7 @@ build
 
 # SDK dir
 sdk
+
+# Downloaded KolibriOS artifacts
+kolibrios-img.7z
+kolibri.img

CMakeLists.txt

@@ -26,3 +26,4 @@ message(STATUS "SDK_SYSROOT_DIR=${SDK_SYSROOT_DIR}")
 
 add_subdirectory(toolchain)
 add_subdirectory(libraries)
+add_subdirectory(tests)

README.md

@@ -1,2 +1,16 @@
 # kolibrios-sdk
 This is a C/C++ SDK for porting software to KolibriOS
+
+## Build
+At the project root:
+```sh
+source activate-env
+cmake -B build
+cmake --build build
+```
+
+## Testing
+Launch KolibriOS with the mounted `SDK_TOOLCHAIN_DIR` directory:
+```sh
+./run-kos.sh
+```

libraries/CMakeLists.txt

@@ -17,5 +17,4 @@ ExternalProject_Add(
         -DCMAKE_C_COMPILER=i586-kolibrios-gcc
         -DCMAKE_C_COMPILER_WORKS=1
         -DCMAKE_INSTALL_PREFIX=${SDK_SYSROOT_DIR}
-    DEPENDS copy-kos-app-lds
 )

run-kos.sh

@@ -0,0 +1,15 @@
+#!/bin/bash
+
+set -eu
+
+download_kolibrios()
+{
+    wget -O "kolibrios-img.7z" https://builds.kolibrios.org/en_US/latest-img.7z
+    7z e kolibrios-img.7z kolibri.img
+}
+
+if [ ! -f "kolibri.img" ]; then
+    download_kolibrios
+fi
+
+qemu-system-i386 -boot a -fda kolibri.img -m 512  -drive file=fat:rw:"$SDK_SYSROOT_DIR" -usbdevice tablet

tests/CMakeLists.txt

@@ -0,0 +1,12 @@
+# Rules for building tests
+
+# Pseudo libc (kos-crt-stub)
+ExternalProject_Add(
+    test-hello
+    SOURCE_DIR  ${CMAKE_CURRENT_SOURCE_DIR}/hello
+    CMAKE_ARGS 
+        -DCMAKE_C_COMPILER=i586-kolibrios-gcc
+        -DCMAKE_C_COMPILER_WORKS=1
+        -DCMAKE_INSTALL_PREFIX=${SDK_SYSROOT_DIR}
+    BUILD_ALWAYS TRUE
+)

tests/hello/hello.c

@@ -0,0 +1,13 @@
+/*
+ * SPDX-License-Identifier: GPL-2.0
+ * Copyright (C) 2025 KolibriOS team
+*/
+
+int main()
+{
+    char *hello = "I: Hello KolibriOS from GCC!\n";
+    while(*hello) {
+        __asm__ __inline__("int $0x40" ::"a"(63), "b"(1), "c"(*hello));
+        hello++;
+    }
+}