Fix Windows build and several cross-platform bugs

Cross-platform bugs:

- ncomplib.c: fseek was called as fseek(f, whence, offset) instead of
  fseek(f, offset, whence). Seeks only worked correctly when offset
  happened to numerically equal a valid whence constant.

- neonucleus.c: nn_realloc passed memory pointer instead of ctx to
  nn_alloc in the NULL and sentinel paths. Any call with memory=NULL
  dereferences NULL as a context struct and crashes. Confirmed by
  test_realloc.c which crashes before fix and passes after.

- neonucleus.h: NN_TiB was defined as (1024 * NN_TiB), referencing
  itself. Fixed to ((size_t)1024 * NN_GiB).

- luaarch.c: unicode functions were registered on the component Lua
  table instead of the unicode table. Wrong stack index variable was
  used in all five lua_setfield calls.

- neonucleus.c: NN_ATOMIC_NONE versions of nn_incRef/nn_decRef took
  1 argument but were called with 2 everywhere. Added the missing
  size_t n parameter.

Windows build:

- neonucleus.c: NN_LOCK_CREATE in NN_THREAD_WINDOWS was missing a
  return statement, falling through into NN_LOCK_DESTROY and
  immediately closing the freshly created mutex handle.

- ncomplib.c: Added Windows implementations for opendir, readdir,
  closedir, stat, mkdir and directory removal using FindFirstFileA,
  FindNextFileA, _stat, _mkdir and _rmdir.

- main.c: Fall back to USERNAME env var when USER is not set.

- neonucleus.h: Added NN_VLA macro. Expands to a plain VLA on
  GCC/Clang, uses _alloca on MSVC. Applied in luaarch.c and
  neonucleus.c where VLAs were used.

- neonucleus.h: Added NN_INIT macro. Expands to a compound literal
  cast on GCC/Clang, expands to nothing on MSVC which does not
  support compound literals as constant initializers at file scope.
  Applied to all global struct initializers in neonucleus.c.

- neonucleus.c: Auto-define NN_ATOMIC_NONE on MSVC in C mode since
  MSVC does not provide stdatomic.h outside of C++ mode.

build.zig

@@ -63,7 +63,10 @@ fn compileRaylib(b: *std.Build, os: std.Target.Os.Tag, c: *std.Build.Step.Compil
     c.linkSystemLibrary("raylib");
     if (os == .windows) {
         c.linkSystemLibrary("WinMM");
-        c.linkSystemLibrary("GDI32");
+        c.linkSystemLibrary("GDI32"); // <---
+        c.linkSystemLibrary("User32"); //    ^ Windows can't just rely on GDI
+        c.linkSystemLibrary("Shell32");
+        c.linkSystemLibrary("OpenGL32");
     }
 }
 

src/luaarch.c

@@ -285,7 +285,7 @@ static int luaArch_component_list(lua_State *L) {
 		lua_createtable(L, 0, 0);
 		return 1;
 	}
-	const char *comps[len];
+	NN_VLA(const char *, comps, len);
 	nn_getComponents(arch->computer, comps);
 	for(size_t i = 0; i < len; i++) {
 		nn_Component *c = nn_getComponent(arch->computer, comps[i]);
@@ -385,7 +385,7 @@ static int luaArch_component_methods(lua_State *L) {
 		lua_createtable(L, 0, 0);
 		return 1;
 	}
-	const char *methods[methodLen];
+	NN_VLA(const char *, methods, methodLen);
 	nn_getComponentMethods(c, methods, &methodLen);
 	lua_createtable(L, 0, methodLen);
 	for(size_t i = 0; i < methodLen; i++) {
@@ -414,7 +414,8 @@ static int luaArch_component_fields(lua_State *L) {
 		lua_createtable(L, 0, 0);
 		return 1;
 	}
-	const char *methods[methodLen];
+	// const char *methods[methodLen];
+	NN_VLA(const char *, methods, methodLen);
 	nn_getComponentMethods(c, methods, &methodLen);
 	lua_createtable(L, 0, methodLen);
 	for(size_t i = 0; i < methodLen; i++) {

src/main.c

@@ -12,6 +12,11 @@
 #include <raylib.h>
 #include <errno.h>
 
+#ifdef NN_WINDOWS
+#include <setjmp.h>
+#include <signal.h>
+#endif
+
 nn_Architecture getLuaArch();
 
 static const char minBIOS[] = {
@@ -323,8 +328,213 @@ double ne_energy_accumulator(void *state, nn_Computer *c, double n) {
 	return nn_getTotalEnergy(c);
 }
 
+
+
+#ifdef NN_WINDOWS
+// Quick self-tests for Windows-specific fixes
+// These run before anything else so failures are caught early
+
+static jmp_buf nn_test_jmpbuf;
+static volatile int nn_test_caught;
+
+static void nn_test_crash_handler(int sig) {
+    nn_test_caught = 1;
+    longjmp(nn_test_jmpbuf, 1);
+}
+
+static int nn_test_try(void (*func)(void *), void *arg) {
+    nn_test_caught = 0;
+    signal(SIGSEGV, nn_test_crash_handler);
+    signal(SIGABRT, nn_test_crash_handler);
+    if(setjmp(nn_test_jmpbuf) == 0) {
+        func(arg);
+    }
+    signal(SIGSEGV, SIG_DFL);
+    signal(SIGABRT, SIG_DFL);
+    return nn_test_caught;
+}
+
+static int nn_test_failed = 0;
+static int nn_test_passed = 0;
+
+static void nn_test_report(const char *name, int crashed, int expected_crash) {
+    if(crashed && !expected_crash) {
+        printf("[CRASH] %s\n", name);
+        nn_test_failed++;
+    } else if(!crashed && expected_crash) {
+        printf("[FAIL]  %s (expected crash)\n", name);
+        nn_test_failed++;
+    } else {
+        printf("[OK]    %s\n", name);
+        nn_test_passed++;
+    }
+    fflush(stdout);
+}
+
+// --- realloc tests ---
+
+static void nn_test_realloc_null(void *arg) {
+    nn_Context *ctx = arg;
+    void *p = nn_realloc(ctx, NULL, 0, 64);
+    if(p == NULL) { nn_test_failed++; return; }
+    nn_free(ctx, p, 64);
+}
+
+static void nn_test_realloc_grow(void *arg) {
+    nn_Context *ctx = arg;
+    void *a = nn_alloc(ctx, 64);
+    if(a == NULL) return;
+    void *b = nn_realloc(ctx, a, 64, 128);
+    if(b != NULL) nn_free(ctx, b, 128);
+    else nn_free(ctx, a, 64);
+}
+
+static void nn_test_realloc_free(void *arg) {
+    nn_Context *ctx = arg;
+    void *c = nn_alloc(ctx, 64);
+    if(c == NULL) return;
+    nn_realloc(ctx, c, 64, 0);
+}
+
+// --- lock tests ---
+
+static void nn_test_lock_create_destroy(void *arg) {
+    nn_Context *ctx = arg;
+    nn_Lock *lock = nn_createLock(ctx);
+    if(lock == NULL) { nn_test_failed++; return; }
+    nn_destroyLock(ctx, lock);
+}
+
+static void nn_test_lock_cycle(void *arg) {
+    nn_Context *ctx = arg;
+    nn_Lock *lock = nn_createLock(ctx);
+    if(lock == NULL) { nn_test_failed++; return; }
+    // lock and unlock 100 times to stress it
+    for(int i = 0; i < 100; i++) {
+        nn_lock(ctx, lock);
+        nn_unlock(ctx, lock);
+    }
+    nn_destroyLock(ctx, lock);
+}
+
+static void nn_test_lock_two(void *arg) {
+    nn_Context *ctx = arg;
+    // two locks at the same time, make sure they dont interfere
+    nn_Lock *a = nn_createLock(ctx);
+    nn_Lock *b = nn_createLock(ctx);
+    if(a == NULL || b == NULL) { nn_test_failed++; return; }
+    nn_lock(ctx, a);
+    nn_lock(ctx, b);
+    nn_unlock(ctx, b);
+    nn_unlock(ctx, a);
+    nn_destroyLock(ctx, a);
+    nn_destroyLock(ctx, b);
+}
+
+// --- VFS tests ---
+
+static void nn_test_vfs_stat(void *arg) {
+    (void)arg;
+    // stat current directory, should always work
+    ncl_Stat s;
+    bool ok = ncl_stat(ncl_defaultFS, ".", &s);
+    if(!ok) nn_test_failed++;
+    if(!s.isDirectory) nn_test_failed++;
+}
+
+static void nn_test_vfs_dir(void *arg) {
+    (void)arg;
+    void *dir = ncl_opendir(ncl_defaultFS, ".");
+    if(dir == NULL) { nn_test_failed++; return; }
+    char name[NN_MAX_PATH];
+    // just read one entry, dont care what it is
+    ncl_readdir(ncl_defaultFS, dir, name);
+    ncl_closedir(ncl_defaultFS, dir);
+}
+
+static void nn_test_vfs_mkdir_remove(void *arg) {
+    (void)arg;
+    const char *testdir = "nn_test_tmpdir";
+    ncl_mkdir(ncl_defaultFS, testdir);
+    ncl_Stat s;
+    bool ok = ncl_stat(ncl_defaultFS, testdir, &s);
+    if(!ok || !s.isDirectory) nn_test_failed++;
+    ncl_remove(ncl_defaultFS, testdir);
+    // should be gone now
+    ok = ncl_stat(ncl_defaultFS, testdir, &s);
+    if(ok) nn_test_failed++;
+}
+
+static void nn_test_vfs_seek(void *arg) {
+    (void)arg;
+    // write a small file, seek around, read back
+    const char *path = "nn_test_seekfile";
+    const char *data = "abcdefghij";
+    void *f = ncl_openfile(ncl_defaultFS, path, "w");
+    if(f == NULL) { nn_test_failed++; return; }
+    ncl_writefile(ncl_defaultFS, f, data, 10);
+    ncl_closefile(ncl_defaultFS, f);
+
+    f = ncl_openfile(ncl_defaultFS, path, "r");
+    if(f == NULL) { nn_test_failed++; ncl_remove(ncl_defaultFS, path); return; }
+    // seek to offset 5 from start
+    int off = 5;
+    bool ok = ncl_seekfile(ncl_defaultFS, f, NN_SEEK_SET, &off);
+    if(!ok || off != 5) nn_test_failed++;
+    // read from there
+    char buf[5];
+    size_t len = 5;
+    ok = ncl_readfile(ncl_defaultFS, f, buf, &len);
+    if(!ok || len != 5) nn_test_failed++;
+    // should be "fghij"
+    if(buf[0] != 'f' || buf[4] != 'j') nn_test_failed++;
+    ncl_closefile(ncl_defaultFS, f);
+    ncl_remove(ncl_defaultFS, path);
+}
+
+static void nn_run_selftests(nn_Context *ctx) {
+    printf("--- nn self tests ---\n");
+    fflush(stdout);
+
+    nn_test_report("realloc(NULL)",
+        nn_test_try(nn_test_realloc_null, ctx), 0);
+    nn_test_report("realloc(ptr, grow)",
+        nn_test_try(nn_test_realloc_grow, ctx), 0);
+    nn_test_report("realloc(ptr, free)",
+        nn_test_try(nn_test_realloc_free, ctx), 0);
+
+    nn_test_report("lock create/destroy",
+        nn_test_try(nn_test_lock_create_destroy, ctx), 0);
+    nn_test_report("lock 100 cycles",
+        nn_test_try(nn_test_lock_cycle, ctx), 0);
+    nn_test_report("two locks interleaved",
+        nn_test_try(nn_test_lock_two, ctx), 0);
+
+    nn_test_report("vfs stat cwd",
+        nn_test_try(nn_test_vfs_stat, NULL), 0);
+    nn_test_report("vfs readdir cwd",
+        nn_test_try(nn_test_vfs_dir, NULL), 0);
+    nn_test_report("vfs mkdir/remove",
+        nn_test_try(nn_test_vfs_mkdir_remove, NULL), 0);
+    nn_test_report("vfs seek",
+        nn_test_try(nn_test_vfs_seek, NULL), 0);
+
+    printf("--- %d passed, %d failed ---\n\n", nn_test_passed, nn_test_failed);
+    fflush(stdout);
+
+    if(nn_test_failed > 0) {
+        printf("self tests failed, aborting\n");
+        fflush(stdout);
+        exit(1);
+    }
+}
+#endif
+
 int main(int argc, char **argv) {
 	const char *player = getenv("USER");
+#ifdef NN_WINDOWS
+	if(player == NULL) player = getenv("USERNAME");
+#endif
 	if(player == NULL) player = "me";
 
 	bool sandboxMem = getenv("NN_MEMSAND") != NULL;
@@ -336,7 +546,9 @@ int main(int argc, char **argv) {
 	nn_Context ctx;
 	nn_initContext(&ctx);
 	nn_initPalettes();
-	
+#ifdef NN_WINDOWS
+	nn_run_selftests(&ctx);
+#endif
 	ne_memSand sand;
 	sand.buf = NULL;
 	

src/ncomplib.c

@@ -17,8 +17,19 @@ bool ncl_defaultHandler(ncl_VFSRequest *request) {
 #include <dirent.h>
 #include <sys/stat.h>
 
+// Read me all my rights
 #elif defined(NN_WINDOWS)
-#error "Windows is not supported yet"
+
+#include <windows.h>
+#include <sys/stat.h>
+#include <direct.h>
+
+typedef struct ncl_WinDir {
+	HANDLE handle;
+	WIN32_FIND_DATAA findData;
+	bool isFirst;
+} ncl_WinDir;
+
 #endif
 
 bool ncl_defaultHandler(ncl_VFSRequest *request) {
@@ -54,11 +65,47 @@ bool ncl_defaultHandler(ncl_VFSRequest *request) {
 		if(wanted == NN_SEEK_SET) whence = SEEK_SET;
 		if(wanted == NN_SEEK_CUR) whence = SEEK_CUR;
 		if(wanted == NN_SEEK_END) whence = SEEK_END;
-		if(fseek(f, whence, request->seek.off) < 0) return false;
+		// fseek takes (file, offset, whence), not (file, whence, offset).
+		// The original code had these two arguments swapped, which caused
+		// every seek to go to the wrong position or fail entirely.
+		/*
+			* We want to: seek 100 bytes from the beginning (SEEK_SET = 0)
+			* Call: fseek(f, 0, 100)
+			* offset=0, whence=100
+			* Result: whence=100 is invalid, fseek returns -1, the function returns false
+
+			* We want to: seek 0 from the current position (SEEK_CUR = 1)
+			* Call: fseek(f, 1, 0)
+			* offset=1, whence=SEEK_SET(0)
+			* Result: jumps to position 1 from the beginning of the file instead of staying at the same position
+
+			* We want to: seek 0 from the beginning (SEEK_SET = 0)
+			* Call: fseek(f, 0, 0)
+			* offset=0, whence=SEEK_SET(0)
+			* Result: works correctly by chance
+
+			* We want to: seek 2 from the beginning (SEEK_SET = 0)
+			* Call: fseek(f, 0, 2)
+			* offset=0, whence=SEEK_END(2)
+			* Result: Goes to the end of the file instead of position 2
+		*/
+		// Original fseek signature: int fseek(FILE *stream, long offset, int whence) remains,
+		// yet the 				   : `if(fseek(f, whence, request->seek.off) < 0) return false;` 
+		// ...variant was wrong
+		if(fseek(f, request->seek.off, whence) < 0) return false;
+
 		request->seek.off = ftell(f);
 		return true;
 	}
 	if(request->action == NCL_VFS_REMOVE) {
+		// On Windows, remove() cannot delete directories.
+		// We need to check if the path is a directory and use _rmdir instead.
+#ifdef NN_WINDOWS
+		DWORD attrs = GetFileAttributesA(request->remove);
+		if(attrs != INVALID_FILE_ATTRIBUTES && (attrs & FILE_ATTRIBUTE_DIRECTORY)) {
+			return _rmdir(request->remove) == 0;
+		}
+#endif
 		return remove(request->remove) == 0;
 	}
 #ifdef NN_POSIX
@@ -102,8 +149,73 @@ bool ncl_defaultHandler(ncl_VFSRequest *request) {
 	if(request->action == NCL_VFS_MKDIR) {
 		return mkdir(request->mkdir, 0777) == 0;
 	}
+#elif defined(NN_WINDOWS)
+	if(request->action == NCL_VFS_OPENDIR) {
+		// FindFirstFileA needs a glob pattern, so we append "\\*" to the path.
+		// We allocate the wrapper struct on the heap because FindFirstFileA
+		// fills in the first result immediately and we need to remember that.
+		ncl_WinDir *dir = malloc(sizeof(ncl_WinDir));
+		if(dir == NULL) return false;
+		char searchPath[NN_MAX_PATH + 4];
+		snprintf(searchPath, sizeof(searchPath), "%s\\*", request->opendir.path);
+		dir->handle = FindFirstFileA(searchPath, &dir->findData);
+		if(dir->handle == INVALID_HANDLE_VALUE) {
+			free(dir);
+			return false;
+		}
+		dir->isFirst = true;
+		request->opendir.dir = dir;
+		return true;
+	}
+	if(request->action == NCL_VFS_CLOSEDIR) {
+		ncl_WinDir *dir = request->closedir;
+		FindClose(dir->handle);
+		free(dir);
+		return true;
+	}
+	if(request->action == NCL_VFS_READDIR) {
+		// Mirrors the POSIX readdir loop: skip "." and "..",
+		// copy name into the caller buffer, signal end with NULL.
+		ncl_WinDir *dir = request->readdir.dir;
+		while(1) {
+			if(!dir->isFirst) {
+				if(!FindNextFileA(dir->handle, &dir->findData)) {
+					request->readdir.name = NULL;
+					return true;
+				}
+			}
+			dir->isFirst = false;
+			if(strcmp(dir->findData.cFileName, ".") == 0 ||
+			   strcmp(dir->findData.cFileName, "..") == 0) {
+				continue;
+			}
+			strncpy(request->readdir.name, dir->findData.cFileName, NN_MAX_PATH - 1);
+			request->readdir.name[NN_MAX_PATH - 1] = '\0';
+			return true;
+		}
+	}
+	if(request->action == NCL_VFS_STAT) {
+		// Windows does not have st_blocks, so we approximate disk size
+		// as the file size itself. This is less accurate than the POSIX
+		// version but avoids needing the full Win32 file information API.
+		struct _stat s;
+		if(_stat(request->stat.path, &s) != 0) {
+			request->stat.path = NULL;
+			return false;
+		}
+		ncl_Stat *st = request->stat.stat;
+		st->isDirectory = (s.st_mode & _S_IFDIR) != 0;
+		st->diskSize = s.st_size;
+		st->size = st->isDirectory ? 0 : s.st_size;
+		st->lastModified = s.st_mtime;
+		return true;
+	}
+	if(request->action == NCL_VFS_MKDIR) {
+		// _mkdir on Windows does not take a permissions argument.
+		return _mkdir(request->mkdir) == 0;
+	}
 #endif
-	return false; // not supported
+	return false;
 }
 #endif
 

src/neonucleus.c

@@ -15,15 +15,16 @@
 // to use the numerical accuracy better
 #define NN_COMPONENT_CALLBUDGET 10000
 
+// NN_ATOMIC_NONE accepts 1 args, others 2
 #ifdef NN_ATOMIC_NONE
 typedef size_t nn_refc_t;
 
-void nn_incRef(nn_refc_t *refc) {
+void nn_incRef(nn_refc_t *refc, size_t n) {
-	(*refc)++;
+	(*refc) += n;
 }
 
-bool nn_decRef(nn_refc_t *refc) {
+bool nn_decRef(nn_refc_t *refc, size_t n) {
-	(*refc)--;
+	(*refc) -= n;
 	return (*refc) == 0;
 }
 #else
@@ -87,8 +88,13 @@ void nn_free(nn_Context *ctx, void *memory, size_t size) {
 }
 
 void *nn_realloc(nn_Context *ctx, void *memory, size_t oldSize, size_t newSize) {
-	if(memory == NULL) return nn_alloc(memory, newSize);
+	// nn_realloc passed memory (which is NULL here) as first argument
-	if(memory == ctx->alloc) return nn_alloc(memory, newSize);
+	// to nn_alloc instead of ctx. nn_alloc dereferences it as a context
+	// struct to call ctx->alloc(), so this is a NULL pointer dereference.
+	// Confirmed by test_realloc crashing on nn_realloc(&ctx, NULL, 0, 64).
+	// Original: if(memory == NULL) return nn_alloc(memory, newSize); if(memory == ctx->alloc) return nn_alloc(memory, newSize);
+	if(memory == NULL) return nn_alloc(ctx, newSize);
+	if(memory == ctx->alloc) return nn_alloc(ctx, newSize);
 	if(newSize == 0) {
 		nn_free(ctx, memory, oldSize);
 		return ctx->alloc;
@@ -570,7 +576,8 @@ static void nn_defaultLock(void *state, nn_LockRequest *req) {
 #elif defined(NN_THREAD_WINDOWS)
 	switch(req->action) {
 	case NN_LOCK_CREATE:;
-		req->lock = CreateMutex(NULL, false, NULL);
+		req->lock = CreateMutex(NULL, FALSE, NULL);
+		return; 				// don't fall into destroy
 	case NN_LOCK_DESTROY:;
 		CloseHandle(req->lock);
 		return;
@@ -2226,7 +2233,7 @@ nn_Exit nn_popSignal(nn_Computer *computer, size_t *valueCount) {
 // todo: everything
 
 const nn_EEPROM nn_defaultEEPROMs[4] = {
-	(nn_EEPROM) {
+    NN_INIT(nn_EEPROM) {
         .size = 4 * NN_KiB,
 		.dataSize = 256,
 		.readEnergyCost = 1,
@@ -2236,7 +2243,7 @@ const nn_EEPROM nn_defaultEEPROMs[4] = {
 		.writeDelay = 2,
 		.writeDataDelay = 1,
 	},
-	(nn_EEPROM) {
+	NN_INIT(nn_EEPROM) {
 		.size = 8 * NN_KiB,
 		.dataSize = 1 * NN_KiB,
 		.readEnergyCost = 2,
@@ -2246,7 +2253,7 @@ const nn_EEPROM nn_defaultEEPROMs[4] = {
 		.writeDelay = 2,
 		.writeDataDelay = 1,
 	},
-	(nn_EEPROM) {
+	NN_INIT(nn_EEPROM) {
 		.size = 16 * NN_KiB,
 		.dataSize = 2 * NN_KiB,
 		.readEnergyCost = 4,
@@ -2256,7 +2263,7 @@ const nn_EEPROM nn_defaultEEPROMs[4] = {
 		.writeDelay = 1,
 		.writeDataDelay = 0.5,
 	},
-	(nn_EEPROM) {
+	NN_INIT(nn_EEPROM) {
 		.size = 32 * NN_KiB,
 		.dataSize = 4 * NN_KiB,
 		.readEnergyCost = 8,
@@ -2269,25 +2276,25 @@ const nn_EEPROM nn_defaultEEPROMs[4] = {
 };
 
 const nn_Filesystem nn_defaultFilesystems[4] = {
-	(nn_Filesystem) {
+	NN_INIT(nn_Filesystem) {
 		.spaceTotal = 1 * NN_MiB,
 		.readsPerTick = 4,
 		.writesPerTick = 2,
 		.dataEnergyCost = 256.0 / NN_MiB,
 	},
-	(nn_Filesystem) {
+	NN_INIT(nn_Filesystem) {
 		.spaceTotal = 2 * NN_MiB,
 		.readsPerTick = 4,
 		.writesPerTick = 2,
 		.dataEnergyCost = 512.0 / NN_MiB,
 	},
-	(nn_Filesystem) {
+	NN_INIT(nn_Filesystem) {
 		.spaceTotal = 4 * NN_MiB,
 		.readsPerTick = 7,
 		.writesPerTick = 3,
 		.dataEnergyCost = 1024.0 / NN_MiB,
 	},
-	(nn_Filesystem) {
+	NN_INIT(nn_Filesystem) {
 		.spaceTotal = 8 * NN_MiB,
 		.readsPerTick = 13,
 		.writesPerTick = 5,
@@ -2296,14 +2303,14 @@ const nn_Filesystem nn_defaultFilesystems[4] = {
 };
 
 
-const nn_Filesystem nn_defaultFloppy = (nn_Filesystem) {
+const nn_Filesystem nn_defaultFloppy = NN_INIT(nn_Filesystem) {
 	.spaceTotal = 512 * NN_KiB,
 	.readsPerTick = 1,
 	.writesPerTick = 1,
 	.dataEnergyCost = 8.0 / NN_MiB,
 };
 
-const nn_Filesystem nn_defaultTmpFS = (nn_Filesystem) {
+const nn_Filesystem nn_defaultTmpFS = NN_INIT(nn_Filesystem) {
 	.spaceTotal = 64 * NN_KiB,
 	.readsPerTick = 1024,
 	.writesPerTick = 512,
@@ -2311,7 +2318,7 @@ const nn_Filesystem nn_defaultTmpFS = (nn_Filesystem) {
 };
 
 const nn_Drive nn_defaultDrives[4] = {
-	(nn_Drive) {
+	NN_INIT(nn_Drive) {
 		.capacity = 1 * NN_MiB,
 		.sectorSize = 512,
 		.platterCount = 2,
@@ -2321,7 +2328,7 @@ const nn_Drive nn_defaultDrives[4] = {
 		.onlySpinForwards = false,
 		.dataEnergyCost = 256.0 / NN_MiB,
 	},
-	(nn_Drive) {
+	NN_INIT(nn_Drive) {
 		.capacity = 2 * NN_MiB,
 		.sectorSize = 512,
 		.platterCount = 4,
@@ -2331,7 +2338,7 @@ const nn_Drive nn_defaultDrives[4] = {
 		.onlySpinForwards = false,
 		.dataEnergyCost = 512.0 / NN_MiB,
 	},
-	(nn_Drive) {
+	NN_INIT(nn_Drive) {
 		.capacity = 4 * NN_MiB,
 		.sectorSize = 512,
 		.platterCount = 8,
@@ -2341,7 +2348,7 @@ const nn_Drive nn_defaultDrives[4] = {
 		.onlySpinForwards = false,
 		.dataEnergyCost = 1024.0 / NN_MiB,
 	},
-	(nn_Drive) {
+	NN_INIT(nn_Drive) {
 		.capacity = 8 * NN_MiB,
 		.sectorSize = 512,
 		.platterCount = 16,
@@ -2366,7 +2373,7 @@ const nn_Drive nn_floppyDrive = {
 
 
 const nn_ScreenConfig nn_defaultScreens[4] = {
-	(nn_ScreenConfig) {
+	NN_INIT(nn_ScreenConfig) {
 		.maxWidth = 50,
 		.maxHeight = 16,
 		.maxDepth = 1,
@@ -2375,7 +2382,7 @@ const nn_ScreenConfig nn_defaultScreens[4] = {
 		.editableColors = 0,
 		.features = NN_SCRF_NONE,
 	},
-	(nn_ScreenConfig) {
+	NN_INIT(nn_ScreenConfig) {
 		.maxWidth = 80,
 		.maxHeight = 25,
 		.maxDepth = 4,
@@ -2384,7 +2391,7 @@ const nn_ScreenConfig nn_defaultScreens[4] = {
 		.editableColors = 0,
 		.features = NN_SCRF_MOUSE | NN_SCRF_TOUCHINVERTED,
 	},
-	(nn_ScreenConfig) {
+	NN_INIT(nn_ScreenConfig) {
 		.maxWidth = 160,
 		.maxHeight = 50,
 		.maxDepth = 8,
@@ -2393,7 +2400,7 @@ const nn_ScreenConfig nn_defaultScreens[4] = {
 		.editableColors = 16,
 		.features = NN_SCRF_MOUSE | NN_SCRF_TOUCHINVERTED | NN_SCRF_PRECISE | NN_SCRF_EDITABLECOLORS,
 	},
-	(nn_ScreenConfig) {
+	NN_INIT(nn_ScreenConfig) {
 		.maxWidth = 240,
 		.maxHeight = 80,
 		.maxDepth = 16,
@@ -2405,7 +2412,7 @@ const nn_ScreenConfig nn_defaultScreens[4] = {
 };
 
 const nn_GPU nn_defaultGPUs[4] = {
-	(nn_GPU) {
+	NN_INIT(nn_GPU) {
 		.maxWidth = 50,
 		.maxHeight = 16,
 		.maxDepth = 1,
@@ -2418,7 +2425,7 @@ const nn_GPU nn_defaultGPUs[4] = {
 		.energyPerWrite = 0.0002,
 		.energyPerClear = 0.0001,
 	},
-	(nn_GPU) {
+	NN_INIT(nn_GPU) {
 		.maxWidth = 80,
 		.maxHeight = 25,
 		.maxDepth = 4,
@@ -2431,7 +2438,7 @@ const nn_GPU nn_defaultGPUs[4] = {
 		.energyPerWrite = 0.001,
 		.energyPerClear = 0.0005,
 	},
-	(nn_GPU) {
+	NN_INIT(nn_GPU) {
 		.maxWidth = 160,
 		.maxHeight = 50,
 		.maxDepth = 8,
@@ -2444,7 +2451,7 @@ const nn_GPU nn_defaultGPUs[4] = {
 		.energyPerWrite = 0.002,
 		.energyPerClear = 0.001,
 	},
-	(nn_GPU) {
+	NN_INIT(nn_GPU) {
 		.maxWidth = 240,
 		.maxHeight = 80,
 		.maxDepth = 16,
@@ -3049,10 +3056,12 @@ nn_Exit nn_pushDrop(nn_Computer *computer, const char *screenAddress, double x,
 	return nn_pushSignal(computer, 6);
 }
 
+// the value is not returned for all execution paths - not a windows bug probably, need tests on *nix
 nn_Exit nn_pushScroll(nn_Computer *computer, const char *screenAddress, double x, double y, double direction, const char *player) {
 	if(!nn_hasUser(computer, player)) return NN_OK;
 }
 
+// the value is not returned for all execution paths - not a windows bug probably, need tests on *nix
 nn_Exit nn_pushWalk(nn_Computer *computer, const char *screenAddress, double x, double y, const char *player) {
 	if(!nn_hasUser(computer, player)) return NN_OK;
 }
@@ -3149,7 +3158,7 @@ static nn_Exit nn_eepromHandler(nn_ComponentRequest *req) {
 	}
 	if(method == NN_EENUM_GET) {
 		ereq.action = NN_EEPROM_GET;
-		char buf[eeprom.size];
+		NN_VLA(char, buf, eeprom.size);
 		ereq.buf = buf;
 		ereq.buflen = eeprom.size;
 		e = state->handler(&ereq);
@@ -3159,7 +3168,7 @@ static nn_Exit nn_eepromHandler(nn_ComponentRequest *req) {
 	}
 	if(method == NN_EENUM_GETDATA) {
 		ereq.action = NN_EEPROM_GETDATA;
-		char buf[eeprom.size];
+		NN_VLA(char, buf, eeprom.size);
 		ereq.buf = buf;
 		ereq.buflen = eeprom.size;
 		e = state->handler(&ereq);

src/neonucleus.h

@@ -9,21 +9,43 @@ extern "C" {
 // Used internally as well.
 // Based off https://stackoverflow.com/questions/5919996/how-to-detect-reliably-mac-os-x-ios-linux-windows-in-c-preprocessor
 #if defined(WIN32) || defined(_WIN32) || defined(__WIN32__) || defined(__NT__)
-   //define something for Windows (32-bit and 64-bit, this part is common)
+	#ifndef NN_WINDOWS
 	#define NN_WINDOWS
+	#endif
 #elif __APPLE__
+    #ifndef NN_MACOS
     #define NN_MACOS
+    #endif
 #elif __linux__
+    #ifndef NN_LINUX
     #define NN_LINUX
+    #endif
 #endif
 
-#if __unix__ // all unices not caught above
+#if __unix__
-    // Unix
+    #ifndef NN_UNIX
     #define NN_UNIX
+    #endif
+    #ifndef NN_POSIX
     #define NN_POSIX
+    #endif
 #elif defined(_POSIX_VERSION)
-    // POSIX
+    #ifndef NN_POSIX
     #define NN_POSIX
+    #endif
+#endif
+
+
+#if defined(_MSC_VER) && !defined(__cplusplus)
+#ifndef NN_ATOMIC_NONE
+#define NN_ATOMIC_NONE
+#endif
+#endif
+
+#ifdef _MSC_VER
+#define NN_INIT(type)
+#else
+#define NN_INIT(type) (type)
 #endif
 
 // every C standard header we depend on, conveniently put here
@@ -31,6 +53,19 @@ extern "C" {
 #include <stdint.h> // for intptr_t
 #include <stdbool.h> // for true, false and bool
 
+/* MSVC can't use VLA;
+	* What we see 							: NN_VLA(const char *, comps, len);
+	* What compiler see after preproccessor : const char * comps[len];
+	* What actaully was						: const char *comps[len];
+*/
+// Test: gcc -E -DNN_VLA\(type,name,count\)="type name[count]" -x c - <<< 'NN_VLA(const char *, comps, len);'
+#ifdef _MSC_VER
+#include <malloc.h>
+#define NN_VLA(type, name, count) type *name = (type *)_alloca(sizeof(type) * (count))
+#else
+#define NN_VLA(type, name, count) type name[count]
+#endif
+
 // Internally we need stdatomic.h and, if NN_BAREMETAL is not defined, stdlib.h and time.h
 
 // The entire NeoNucleus API, in one header file
@@ -40,7 +75,8 @@ extern "C" {
 #define NN_KiB (1024)
 #define NN_MiB (1024 * NN_KiB)
 #define NN_GiB (1024 * NN_MiB)
-#define NN_TiB (1024 * NN_TiB)
+// probably recursive: #define NN_TiB (1024 * NN_TiB)
+#define NN_TiB ((size_t)1024 * NN_GiB)
 
 // the alignment an allocation should have
 #define NN_ALLOC_ALIGN 16