Implement file system API and add shutdown functionality for desktop builds

core/CMakeLists.txt

@@ -31,6 +31,7 @@ else()
     # --------------------------------------------------------------------------
 
     message(STATUS "[Nova64] Building as Desktop Shared Library...")
+    add_compile_definitions(NOVA64_SHUTDOWN_AVAILABLE) # Enable shutdown functionality for desktop builds
 
     # --------------------------------------------------------------------------
     # FreeRTOS Configuration

core/include/nova64_core.h

@@ -1,9 +1,10 @@
 #ifndef NOVA64_CORE_H
 #define NOVA64_CORE_H
 
+#include <stdarg.h>
 #include <stdbool.h>
 #include <stdint.h>
-#include <stdarg.h>
+
 
 // Cross-platform DLL export/import visibility macros
 #if defined(_WIN32) || defined(__CYGWIN__)
@@ -42,16 +43,27 @@ typedef void (*nova64_audio_output_cb_t)(const int16_t *samples,
                                          uint32_t count);
 
 /**
- * @brief Callback to read sectors from the SD card.
- * @param sector_idx The zero-based sector index to read.
- * @param destination_buffer Pointer to memory where sector data should be
- * copied.
- * @param sector_count Number of 512-byte sectors to read.
- * @return True on success, false on read error.
+ * @brief Callback to read data from the SD card.
+ * @param slot_idx Zero-based cartridge slot index.
+ * @param file_path Null-terminated path to the file to read.
+ * @param destination_buffer Pointer to memory where file data should be copied.
+ * @param destination_length Maximum number of bytes available in the
+ * destination buffer.
+ * @return Number of bytes read on success, negative value on read error.
  */
-typedef bool (*nova64_sd_read_sector_cb_t)(uint32_t sector_idx,
-                                           uint8_t *destination_buffer,
-                                           uint32_t sector_count);
+typedef int32_t (*nova64_sd_read_file_cb_t)(uint32_t slot_idx,
+                                            const char *file_path,
+                                            uint8_t *destination_buffer,
+                                            uint32_t destination_length);
+
+/**
+ * @brief Callback to retrieve the size of a file on the SD card.
+ * @param slot_idx Zero-based cartridge slot index.
+ * @param file_path Null-terminated path to the file.
+ * @return File size in bytes on success, negative value on error.
+ */
+typedef int32_t (*nova64_sd_get_file_size_cb_t)(uint32_t slot_idx,
+                                                 const char *file_path);
 
 /**
  * @brief Callback triggered when a cartridge state change occurs (e.g.
@@ -60,7 +72,7 @@ typedef bool (*nova64_sd_read_sector_cb_t)(uint32_t sector_idx,
  * @param is_inserted True if a cartridge is detected, false if ejected.
  */
 typedef void (*nova64_cartridge_status_cb_t)(uint32_t slot_idx,
-                                            bool is_inserted);
+                                             bool is_inserted);
 
 /**
  * @brief Callback for core log output.
@@ -79,7 +91,8 @@ typedef void (*nova64_log_cb_t)(const char *message);
 typedef struct {
   nova64_display_flush_cb_t display_flush;
   nova64_audio_output_cb_t audio_output;
-  nova64_sd_read_sector_cb_t sd_read_sector;
+  nova64_sd_read_file_cb_t sd_read_file;
+  nova64_sd_get_file_size_cb_t sd_get_file_size;
   nova64_cartridge_status_cb_t cartridge_status;
   nova64_log_cb_t log_message;
 } nova64_io_interface_t;
@@ -104,11 +117,13 @@ NOVA64_API bool nova64_init(const nova64_io_interface_t *io_interface);
  */
 NOVA64_API int32_t nova64_main();
 
+#if defined(NOVA64_SHUTDOWN_AVAILABLE)
 /**
  * @brief Requests shutdown of the FreeRTOS scheduler.
  * @return True if the shutdown request was issued, false otherwise.
  */
 NOVA64_API bool nova64_shutdown(void);
+#endif
 
 /**
  * @brief Retrieves the engine version integer.

core/include/nova64_fs.h

@@ -0,0 +1,39 @@
+#ifndef NOVA64_FS_H
+#define NOVA64_FS_H
+
+#include <stdbool.h>
+#include <stdint.h>
+#include <stddef.h>
+
+/* ========================================================================== */
+/* File System API                                                            */
+/* ========================================================================== */
+
+/**
+ * @brief Reads a file from the filesystem into a buffer.
+ *        Supports drive identifiers: "SYS:" (internal system store),
+ *        "EXA:" (cartridge slot 0), "EXB:" (cartridge slot 1), etc.
+ * @param file_path Null-terminated file path with drive identifier
+ *                  (e.g., "SYS:/init.wasm" or "EXA:/game.wasm").
+ * @param buffer Pointer to destination buffer where file contents will be
+ *               copied.
+ * @param buffer_size Size in bytes of the destination buffer.
+ * @return True if file was successfully read into buffer, false on error
+ *         (file not found, read error, or buffer too small).
+ * @note Uses the sd_read_sector callback from nova64_io_interface_t.
+ *       The callback must be registered via nova64_init() before calling
+ *       this function.
+ */
+bool nova64_read_file_to_buffer(const char *file_path, uint8_t *buffer,
+                                size_t buffer_size);
+
+/**
+ * @brief Gets the size of a file in the filesystem.
+ * @param file_path Null-terminated file path with drive identifier
+ *                  (e.g., "SYS:/init.wasm" or "EXA:/game.wasm").
+ * @return Size of the file in bytes on success, or -1 on error
+ *         (file not found, read error, etc.).
+ */
+int32_t nova64_get_file_size(const char *file_path);
+
+#endif // NOVA64_FS_H

core/include/nova64_internal.h

@@ -1,6 +1,10 @@
 #ifndef NOVA64_INTERNAL_H
 #define NOVA64_INTERNAL_H
 
+#include "nova64_core.h"
+
 void nova64_log(const char *format, ...);
 
+const nova64_io_interface_t *nova64_get_io_interface(void);
+
 #endif // NOVA64_INTERNAL_H

core/include/wasm_runner.h

@@ -4,12 +4,6 @@
 #include <stdbool.h>
 #include <stdint.h>
 
-typedef enum {
-  wasm_runner_role_main = 0,
-  wasm_runner_role_status,
-  wasm_runner_role_background,
-} wasm_runner_role_t;
-
 typedef struct wasm_runner_instance wasm_runner_instance_t;
 
 typedef struct {

core/src/nova64_core.c

@@ -1,13 +1,12 @@
 #include "nova64_core.h"
-#include "nova64_internal.h"
 #include "FreeRTOS.h"
+#include "nova64_internal.h"
 #include "queue.h"
 #include "task.h"
 #include "wasm_runner.h"
 #include <stdarg.h>
 #include <stdio.h>
 
-
 #if defined(ESP_PLATFORM)
 #include "esp_pm.h"
 #include "esp_rom_sys.h"
@@ -26,8 +25,11 @@ static const nova64_io_interface_t *g_io_interface = NULL;
 static QueueHandle_t event_queue = NULL;
 static TaskHandle_t boot_task_handle = NULL;
 static TaskHandle_t launcher_task_handle = NULL;
+
+#if defined(NOVA64_SHUTDOWN_AVAILABLE)
 static TaskHandle_t shutdown_task_handle = NULL;
 static volatile bool shutdown_requested = false;
+#endif
 
 static const char *const kInternalLauncherPath = "SYS:/launcher.wasm";
 
@@ -83,6 +85,7 @@ static bool start_launcher_task(void) {
   return true;
 }
 
+#if defined(NOVA64_SHUTDOWN_AVAILABLE)
 static void nova64_shutdown_task(void *params) {
   (void)params;
 
@@ -110,6 +113,7 @@ static bool start_shutdown_task(void) {
   nova64_log("Shutdown task created successfully.\n");
   return true;
 }
+#endif
 
 static void nova64_boot_task(void *params) {
   (void)params;
@@ -137,6 +141,10 @@ static void nova64_boot_task(void *params) {
   vTaskDelete(NULL);
 }
 
+const nova64_io_interface_t *nova64_get_io_interface(void) {
+  return g_io_interface;
+}
+
 NOVA64_API bool nova64_init(const nova64_io_interface_t *io_interface) {
   if (is_initialized || io_interface == NULL) {
     return false;
@@ -144,7 +152,10 @@ NOVA64_API bool nova64_init(const nova64_io_interface_t *io_interface) {
 
   g_io_interface_storage = *io_interface;
   g_io_interface = &g_io_interface_storage;
+
+#if defined(NOVA64_SHUTDOWN_AVAILABLE)
   shutdown_requested = false;
+#endif
 
   nova64_log("System Initializing...\n");
 
@@ -154,9 +165,11 @@ NOVA64_API bool nova64_init(const nova64_io_interface_t *io_interface) {
     return false;
   }
 
+#if defined(NOVA64_SHUTDOWN_AVAILABLE)
   if (!start_shutdown_task()) {
     return false;
   }
+#endif
 
   nova64_log("Starting boot process...\n");
   BaseType_t created =
@@ -186,6 +199,7 @@ NOVA64_API int32_t nova64_main() {
   return 1;
 }
 
+#if defined(NOVA64_SHUTDOWN_AVAILABLE)
 NOVA64_API bool nova64_shutdown(void) {
   if (!is_initialized) {
     return false;
@@ -195,6 +209,7 @@ NOVA64_API bool nova64_shutdown(void) {
   shutdown_requested = true;
   return true;
 }
+#endif
 
 NOVA64_API uint32_t nova64_get_version(void) {
   return 0x010000; // v1.0.0

core/src/nova64_fs.c

@@ -0,0 +1,98 @@
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <string.h>
+#include "nova64_fs.h"
+#include "nova64_core.h"
+#include "nova64_internal.h"
+
+/* Helper for parsing the drive prefix from a path like "SYS:/file" or "EXA:/file".
+ * Returns the drive index on success, or -1 on failure. */
+static int parse_drive_index(const char *path)
+{
+    if (!path || path[0] == '\0') {
+        return -1;
+    }
+
+    if (strncmp(path, "SYS:/", 5) == 0) {
+        return 0;
+    }
+
+    if (strncmp(path, "EX", 2) == 0 && path[3] == ':' && path[4] == '/') {
+        char drive_letter = path[2];
+        if (drive_letter >= 'A' && drive_letter <= 'Z') {
+            return drive_letter - ('A' - 1);
+        }
+    }
+
+    return -1;
+}
+
+bool nova64_read_file_to_buffer(const char *file_path,
+                               uint8_t *buffer,
+                               size_t buffer_size)
+{
+    if (!file_path || !buffer || buffer_size == 0) {
+        return false;
+    }
+
+    int drive_index = parse_drive_index(file_path);
+    if (drive_index < 0) {
+        return false;
+    }
+
+    const char *relative_path = file_path + 5;
+    if (*relative_path == '\0') {
+        return false;
+    }
+
+    const nova64_io_interface_t *io = nova64_get_io_interface();
+    if (!io || !io->sd_read_file || !io->sd_get_file_size) {
+        return false;
+    }
+
+    /* Get the file size first */
+    int32_t file_size = io->sd_get_file_size(drive_index, relative_path);
+    if (file_size < 0) {
+        return false;
+    }
+
+    /* Determine how much to read */
+    size_t bytes_to_read = (size_t)file_size;
+    if (bytes_to_read > buffer_size) {
+        bytes_to_read = buffer_size;
+    }
+
+    /* Read the entire file into the buffer */
+    int32_t bytes_read = io->sd_read_file(drive_index, relative_path, buffer, bytes_to_read);
+    if (bytes_read < 0) {
+        return false;
+    }
+
+    return bytes_read > 0;
+}
+
+
+int32_t nova64_get_file_size(const char *file_path)
+{
+    if (!file_path) {
+        return -1;
+    }
+
+    int drive_index = parse_drive_index(file_path);
+    if (drive_index < 0) {
+        return -1;
+    }
+
+    const char *relative_path = file_path + 5;
+    if (*relative_path == '\0') {
+        return -1;
+    }
+
+    const nova64_io_interface_t *io = nova64_get_io_interface();
+    if (!io || !io->sd_get_file_size) {
+        return -1;
+    }
+
+    return io->sd_get_file_size(drive_index, relative_path);
+}

core/src/wasm_runner.c

@@ -1,6 +1,8 @@
 #include "wasm_runner.h"
+#include "nova64_fs.h"
 #include "nova64_internal.h"
 #include "wasm_export.h"
+#include <stdlib.h>
 
 struct wasm_runner_instance {
   void *native_instance;
@@ -9,8 +11,40 @@ struct wasm_runner_instance {
   wasm_runner_instance_t *next;
 };
 
+char error_buf[128];
+uint32_t stack_size = 8092, heap_size = 8092;
+
 bool wasm_runner_initialize(void) {
+
   wasm_runtime_init();
   nova64_log("WASM runtime initialized successfully.\n");
+
+  const char *module_file = "SYS:/init.wasm";
+  int32_t file_size = nova64_get_file_size(module_file);
+  if (file_size <= 0) {
+    nova64_log("Failed to determine WASM module size.\n");
+    return false;
+  }
+
+  unsigned char *buffer = malloc((size_t)file_size);
+  if (!buffer) {
+    nova64_log("Failed to allocate WASM module buffer.\n");
+    return false;
+  }
+
+  if (!nova64_read_file_to_buffer(module_file, buffer, (size_t)file_size)) {
+    nova64_log("Failed to read WASM module into buffer.\n");
+    free(buffer);
+    return false;
+  }
+
+  wasm_module_t module = wasm_runtime_load(buffer, (uint32_t)file_size,
+                                           error_buf, sizeof(error_buf));
+
+  wasm_module_inst_t module_inst = wasm_runtime_instantiate(
+      module, stack_size, heap_size, error_buf, sizeof(error_buf));
+
+  wasm_exec_env_t exec_env = wasm_runtime_create_exec_env(module_inst, stack_size);
+  
   return true;
 }

simulator/Nova64Core.cs

@@ -10,8 +10,11 @@ internal static class Nova64Core
     [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
     public delegate void AudioOutputDelegate(IntPtr samples, uint count);
 
-    [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
-    public delegate bool SdReadSectorDelegate(uint sectorIdx, IntPtr destinationBuffer, uint sectorCount);
+    [UnmanagedFunctionPointer(CallingConvention.Cdecl, CharSet = CharSet.Ansi)]
+    public delegate int SdReadFileDelegate(uint slotIdx, string filePath, IntPtr destinationBuffer, uint destinationLength);
+
+    [UnmanagedFunctionPointer(CallingConvention.Cdecl, CharSet = CharSet.Ansi)]
+    public delegate int SdGetFileSizeDelegate(uint slotIdx, string filePath);
 
     [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
     public delegate void CartridgeStatusDelegate(uint slotIdx, bool isInserted);
@@ -24,7 +27,8 @@ internal static class Nova64Core
     {
         public IntPtr display_flush;
         public IntPtr audio_output;
-        public IntPtr sd_read_sector;
+        public IntPtr sd_read_file;
+        public IntPtr sd_get_file_size;
         public IntPtr cartridge_status;
         public IntPtr log_message;
     }

simulator/Nova64Simulator.csproj

@@ -12,6 +12,14 @@
     <NativeLibDir>$(NativeLibDir)</NativeLibDir>
   </PropertyGroup>
 
+  <ItemGroup>
+    <PackageReference Include="Zio" Version="0.24.0" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <Content Include="sd\**\*" CopyToOutputDirectory="PreserveNewest" CopyToPublishDirectory="PreserveNewest" />
+  </ItemGroup>
+
   <ItemGroup Condition="'$(NativeLibDir)' != ''">
     <Content Include="$(NativeLibDir)\nova64_core.dll" Condition="Exists('$(NativeLibDir)\nova64_core.dll')" CopyToOutputDirectory="IfDifferent" />
     <Content Include="$(NativeLibDir)\libnova64_core.so" Condition="Exists('$(NativeLibDir)\libnova64_core.so')" CopyToOutputDirectory="IfDifferent" />

simulator/Program.cs

@@ -1,12 +1,77 @@
 using System;
+using System.IO;
 using System.Runtime.InteropServices;
 using System.Threading;
+using Zio;
+using Zio.FileSystems;
 
 internal static class Program
 {
+    private static readonly IFileSystem SdFileSystem = new PhysicalFileSystem();
+    private static readonly UPath SdRoot = new UPath(Path.Combine(AppContext.BaseDirectory, "sd").Replace('\\', '/').Replace("C:", "/mnt/c"));
+
+    private static UPath GetSlotFilePath(uint slotIdx, string filePath)
+    {
+        var normalizedPath = (filePath ?? string.Empty).Replace('\\', '/').TrimStart('/');
+        return SdRoot / $"slot{slotIdx}" / normalizedPath;
+    }
+
     private static readonly Nova64Core.DisplayFlushDelegate DisplayFlush = (buffer, width, height) => { };
     private static readonly Nova64Core.AudioOutputDelegate AudioOutput = (samples, count) => { };
-    private static readonly Nova64Core.SdReadSectorDelegate SdReadSector = (sectorIdx, destinationBuffer, sectorCount) => false;
+    private static readonly Nova64Core.SdReadFileDelegate SdReadFile = (slotIdx, filePath, destinationBuffer, destinationLength) =>
+    {
+        var path = GetSlotFilePath(slotIdx, filePath);
+        Console.WriteLine($"[Core] SD read request: slot {slotIdx}, file '{filePath}', resolved path '{path}' destination length {destinationLength}");
+
+        if (destinationBuffer == IntPtr.Zero)
+        {
+            Console.WriteLine("[Core] SD read request failed: destination buffer is null.");
+            return -1;
+        }
+
+        if (!SdFileSystem.FileExists(path))
+        {
+            Console.WriteLine($"[Core] SD read request failed: file not found '{path}'");
+            return -1;
+        }
+
+        try
+        {
+            using var stream = SdFileSystem.OpenFile(path, FileMode.Open, FileAccess.Read, FileShare.Read);
+            var bytesToRead = (int)Math.Min(destinationLength, stream.Length);
+            var buffer = new byte[bytesToRead];
+            var bytesRead = stream.Read(buffer, 0, bytesToRead);
+            Marshal.Copy(buffer, 0, destinationBuffer, bytesRead);
+            return bytesRead;
+        }
+        catch (Exception ex)
+        {
+            Console.WriteLine($"[Core] SD read request failed: {ex.Message}");
+            return -1;
+        }
+    };
+    private static readonly Nova64Core.SdGetFileSizeDelegate SdGetFileSize = (slotIdx, filePath) =>
+    {
+        var path = GetSlotFilePath(slotIdx, filePath);
+        Console.WriteLine($"[Core] SD get file size request: slot {slotIdx}, file '{filePath}', resolved path '{path}'");
+
+        if (!SdFileSystem.FileExists(path))
+        {
+            Console.WriteLine($"[Core] SD get file size failed: file not found '{path}'");
+            return -1;
+        }
+
+        try
+        {
+            var length = SdFileSystem.GetFileLength(path);
+            return length > int.MaxValue ? -1 : (int)length;
+        }
+        catch (Exception ex)
+        {
+            Console.WriteLine($"[Core] SD get file size failed: {ex.Message}");
+            return -1;
+        }
+    };
     private static readonly Nova64Core.CartridgeStatusDelegate CartridgeStatus = (slotIdx, isInserted) => { };
     private static readonly Nova64Core.LogMessageDelegate LogMessage = (message) =>
     {
@@ -51,7 +116,8 @@ internal static class Program
             {
                 display_flush = Marshal.GetFunctionPointerForDelegate(DisplayFlush),
                 audio_output = Marshal.GetFunctionPointerForDelegate(AudioOutput),
-                sd_read_sector = Marshal.GetFunctionPointerForDelegate(SdReadSector),
+                sd_read_file = Marshal.GetFunctionPointerForDelegate(SdReadFile),
+                sd_get_file_size = Marshal.GetFunctionPointerForDelegate(SdGetFileSize),
                 cartridge_status = Marshal.GetFunctionPointerForDelegate(CartridgeStatus),
                 log_message = Marshal.GetFunctionPointerForDelegate(LogMessage)
             };

software/init.go

@@ -0,0 +1,15 @@
+package main
+
+// Declare a main function, this is the entrypoint into our go module
+// That will be run. In our example, we won't need this
+func main() {}
+
+// This exports an add function.
+// It takes in two 32-bit integer values
+// And returns a 32-bit integer value.
+// To make this function callable from JavaScript,
+// we need to add the: "export add" comment above the function
+//export add
+func add(x int, y int) int {
+	return x + y
+}