Report non recoverable errors on the playerui-test

5 files changed, 279 insertions, 44 deletions

diff --git a/example.asm b/example.asm
index 992823f..7584074 100644
--- a/example.asm
+++ b/example.asm
@@ -76,6 +76,7 @@ update_done:
     call draw_sprite
 
     ; wait 1 frame
+    sif
     halt
 
     pop b
diff --git a/font.h b/font.h
new file mode 100644
index 0000000..9385f09
--- /dev/null
+++ b/font.h
@@ -0,0 +1,135 @@
+#ifndef _FONT_H
+#define _FONT_H
+
+static uint8_t font[128][8] = {
+    { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
+    { 0x7e, 0x81, 0xa5, 0x81, 0xbd, 0x99, 0x81, 0x7e },
+    { 0x7e, 0xff, 0xdb, 0xff, 0xc3, 0xe7, 0xff, 0x7e },
+    { 0x6c, 0xfe, 0xfe, 0xfe, 0x7c, 0x38, 0x10, 0x00 },
+    { 0x10, 0x38, 0x7c, 0xfe, 0x7c, 0x38, 0x10, 0x00 },
+    { 0x38, 0x7c, 0x38, 0xfe, 0xfe, 0x7c, 0x38, 0x7c },
+    { 0x10, 0x10, 0x38, 0x7c, 0xfe, 0x7c, 0x38, 0x7c },
+    { 0x00, 0x00, 0x18, 0x3c, 0x3c, 0x18, 0x00, 0x00 },
+    { 0xff, 0xff, 0xe7, 0xc3, 0xc3, 0xe7, 0xff, 0xff },
+    { 0x00, 0x3c, 0x66, 0x42, 0x42, 0x66, 0x3c, 0x00 },
+    { 0xff, 0xc3, 0x99, 0xbd, 0xbd, 0x99, 0xc3, 0xff },
+    { 0x0f, 0x07, 0x0f, 0x7d, 0xcc, 0xcc, 0xcc, 0x78 },
+    { 0x3c, 0x66, 0x66, 0x66, 0x3c, 0x18, 0x7e, 0x18 },
+    { 0x3f, 0x33, 0x3f, 0x30, 0x30, 0x70, 0xf0, 0xe0 },
+    { 0x7f, 0x63, 0x7f, 0x63, 0x63, 0x67, 0xe6, 0xc0 },
+    { 0x99, 0x5a, 0x3c, 0xe7, 0xe7, 0x3c, 0x5a, 0x99 },
+    { 0x80, 0xe0, 0xf8, 0xfe, 0xf8, 0xe0, 0x80, 0x00 },
+    { 0x02, 0x0e, 0x3e, 0xfe, 0x3e, 0x0e, 0x02, 0x00 },
+    { 0x18, 0x3c, 0x7e, 0x18, 0x18, 0x7e, 0x3c, 0x18 },
+    { 0x66, 0x66, 0x66, 0x66, 0x66, 0x00, 0x66, 0x00 },
+    { 0x7f, 0xdb, 0xdb, 0x7b, 0x1b, 0x1b, 0x1b, 0x00 },
+    { 0x3e, 0x63, 0x38, 0x6c, 0x6c, 0x38, 0xcc, 0x78 },
+    { 0x00, 0x00, 0x00, 0x00, 0x7e, 0x7e, 0x7e, 0x00 },
+    { 0x18, 0x3c, 0x7e, 0x18, 0x7e, 0x3c, 0x18, 0xff },
+    { 0x18, 0x3c, 0x7e, 0x18, 0x18, 0x18, 0x18, 0x00 },
+    { 0x18, 0x18, 0x18, 0x18, 0x7e, 0x3c, 0x18, 0x00 },
+    { 0x00, 0x18, 0x0c, 0xfe, 0x0c, 0x18, 0x00, 0x00 },
+    { 0x00, 0x30, 0x60, 0xfe, 0x60, 0x30, 0x00, 0x00 },
+    { 0x00, 0x00, 0xc0, 0xc0, 0xc0, 0xfe, 0x00, 0x00 },
+    { 0x00, 0x24, 0x66, 0xff, 0x66, 0x24, 0x00, 0x00 },
+    { 0x00, 0x18, 0x3c, 0x7e, 0xff, 0xff, 0x00, 0x00 },
+    { 0x00, 0xff, 0xff, 0x7e, 0x3c, 0x18, 0x00, 0x00 },
+    { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
+    { 0x30, 0x78, 0x78, 0x30, 0x30, 0x00, 0x30, 0x00 },
+    { 0x6c, 0x6c, 0x6c, 0x00, 0x00, 0x00, 0x00, 0x00 },
+    { 0x6c, 0x6c, 0xfe, 0x6c, 0xfe, 0x6c, 0x6c, 0x00 },
+    { 0x30, 0x7c, 0xc0, 0x78, 0x0c, 0xf8, 0x30, 0x00 },
+    { 0x00, 0xc6, 0xcc, 0x18, 0x30, 0x66, 0xc6, 0x00 },
+    { 0x38, 0x6c, 0x38, 0x76, 0xdc, 0xcc, 0x76, 0x00 },
+    { 0x60, 0x60, 0xc0, 0x00, 0x00, 0x00, 0x00, 0x00 },
+    { 0x18, 0x30, 0x60, 0x60, 0x60, 0x30, 0x18, 0x00 },
+    { 0x60, 0x30, 0x18, 0x18, 0x18, 0x30, 0x60, 0x00 },
+    { 0x00, 0x66, 0x3c, 0xff, 0x3c, 0x66, 0x00, 0x00 },
+    { 0x00, 0x30, 0x30, 0xfc, 0x30, 0x30, 0x00, 0x00 },
+    { 0x00, 0x00, 0x00, 0x00, 0x00, 0x30, 0x30, 0x60 },
+    { 0x00, 0x00, 0x00, 0xfc, 0x00, 0x00, 0x00, 0x00 },
+    { 0x00, 0x00, 0x00, 0x00, 0x00, 0x30, 0x30, 0x00 },
+    { 0x06, 0x0c, 0x18, 0x30, 0x60, 0xc0, 0x80, 0x00 },
+    { 0x7c, 0xc6, 0xce, 0xde, 0xf6, 0xe6, 0x7c, 0x00 },
+    { 0x30, 0x70, 0x30, 0x30, 0x30, 0x30, 0xfc, 0x00 },
+    { 0x78, 0xcc, 0x0c, 0x38, 0x60, 0xcc, 0xfc, 0x00 },
+    { 0x78, 0xcc, 0x0c, 0x38, 0x0c, 0xcc, 0x78, 0x00 },
+    { 0x1c, 0x3c, 0x6c, 0xcc, 0xfe, 0x0c, 0x1e, 0x00 },
+    { 0xfc, 0xc0, 0xf8, 0x0c, 0x0c, 0xcc, 0x78, 0x00 },
+    { 0x38, 0x60, 0xc0, 0xf8, 0xcc, 0xcc, 0x78, 0x00 },
+    { 0xfc, 0xcc, 0x0c, 0x18, 0x30, 0x30, 0x30, 0x00 },
+    { 0x78, 0xcc, 0xcc, 0x78, 0xcc, 0xcc, 0x78, 0x00 },
+    { 0x78, 0xcc, 0xcc, 0x7c, 0x0c, 0x18, 0x70, 0x00 },
+    { 0x00, 0x30, 0x30, 0x00, 0x00, 0x30, 0x30, 0x00 },
+    { 0x00, 0x30, 0x30, 0x00, 0x00, 0x30, 0x30, 0x60 },
+    { 0x18, 0x30, 0x60, 0xc0, 0x60, 0x30, 0x18, 0x00 },
+    { 0x00, 0x00, 0xfc, 0x00, 0x00, 0xfc, 0x00, 0x00 },
+    { 0x60, 0x30, 0x18, 0x0c, 0x18, 0x30, 0x60, 0x00 },
+    { 0x78, 0xcc, 0x0c, 0x18, 0x30, 0x00, 0x30, 0x00 },
+    { 0x7c, 0xc6, 0xde, 0xde, 0xde, 0xc0, 0x78, 0x00 },
+    { 0x30, 0x78, 0xcc, 0xcc, 0xfc, 0xcc, 0xcc, 0x00 },
+    { 0xfc, 0x66, 0x66, 0x7c, 0x66, 0x66, 0xfc, 0x00 },
+    { 0x3c, 0x66, 0xc0, 0xc0, 0xc0, 0x66, 0x3c, 0x00 },
+    { 0xf8, 0x6c, 0x66, 0x66, 0x66, 0x6c, 0xf8, 0x00 },
+    { 0xfe, 0x62, 0x68, 0x78, 0x68, 0x62, 0xfe, 0x00 },
+    { 0xfe, 0x62, 0x68, 0x78, 0x68, 0x60, 0xf0, 0x00 },
+    { 0x3c, 0x66, 0xc0, 0xc0, 0xce, 0x66, 0x3e, 0x00 },
+    { 0xcc, 0xcc, 0xcc, 0xfc, 0xcc, 0xcc, 0xcc, 0x00 },
+    { 0x78, 0x30, 0x30, 0x30, 0x30, 0x30, 0x78, 0x00 },
+    { 0x1e, 0x0c, 0x0c, 0x0c, 0xcc, 0xcc, 0x78, 0x00 },
+    { 0xe6, 0x66, 0x6c, 0x78, 0x6c, 0x66, 0xe6, 0x00 },
+    { 0xf0, 0x60, 0x60, 0x60, 0x62, 0x66, 0xfe, 0x00 },
+    { 0xc6, 0xee, 0xfe, 0xfe, 0xd6, 0xc6, 0xc6, 0x00 },
+    { 0xc6, 0xe6, 0xf6, 0xde, 0xce, 0xc6, 0xc6, 0x00 },
+    { 0x38, 0x6c, 0xc6, 0xc6, 0xc6, 0x6c, 0x38, 0x00 },
+    { 0xfc, 0x66, 0x66, 0x7c, 0x60, 0x60, 0xf0, 0x00 },
+    { 0x78, 0xcc, 0xcc, 0xcc, 0xdc, 0x78, 0x1c, 0x00 },
+    { 0xfc, 0x66, 0x66, 0x7c, 0x6c, 0x66, 0xe6, 0x00 },
+    { 0x78, 0xcc, 0xe0, 0x70, 0x1c, 0xcc, 0x78, 0x00 },
+    { 0xfc, 0xb4, 0x30, 0x30, 0x30, 0x30, 0x78, 0x00 },
+    { 0xcc, 0xcc, 0xcc, 0xcc, 0xcc, 0xcc, 0xfc, 0x00 },
+    { 0xcc, 0xcc, 0xcc, 0xcc, 0xcc, 0x78, 0x30, 0x00 },
+    { 0xc6, 0xc6, 0xc6, 0xd6, 0xfe, 0xee, 0xc6, 0x00 },
+    { 0xc6, 0xc6, 0x6c, 0x38, 0x38, 0x6c, 0xc6, 0x00 },
+    { 0xcc, 0xcc, 0xcc, 0x78, 0x30, 0x30, 0x78, 0x00 },
+    { 0xfe, 0xc6, 0x8c, 0x18, 0x32, 0x66, 0xfe, 0x00 },
+    { 0x78, 0x60, 0x60, 0x60, 0x60, 0x60, 0x78, 0x00 },
+    { 0xc0, 0x60, 0x30, 0x18, 0x0c, 0x06, 0x02, 0x00 },
+    { 0x78, 0x18, 0x18, 0x18, 0x18, 0x18, 0x78, 0x00 },
+    { 0x10, 0x38, 0x6c, 0xc6, 0x00, 0x00, 0x00, 0x00 },
+    { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xff },
+    { 0x30, 0x30, 0x18, 0x00, 0x00, 0x00, 0x00, 0x00 },
+    { 0x00, 0x00, 0x78, 0x0c, 0x7c, 0xcc, 0x76, 0x00 },
+    { 0xe0, 0x60, 0x60, 0x7c, 0x66, 0x66, 0xdc, 0x00 },
+    { 0x00, 0x00, 0x78, 0xcc, 0xc0, 0xcc, 0x78, 0x00 },
+    { 0x1c, 0x0c, 0x0c, 0x7c, 0xcc, 0xcc, 0x76, 0x00 },
+    { 0x00, 0x00, 0x78, 0xcc, 0xfc, 0xc0, 0x78, 0x00 },
+    { 0x38, 0x6c, 0x60, 0xf0, 0x60, 0x60, 0xf0, 0x00 },
+    { 0x00, 0x00, 0x76, 0xcc, 0xcc, 0x7c, 0x0c, 0xf8 },
+    { 0xe0, 0x60, 0x6c, 0x76, 0x66, 0x66, 0xe6, 0x00 },
+    { 0x30, 0x00, 0x70, 0x30, 0x30, 0x30, 0x78, 0x00 },
+    { 0x0c, 0x00, 0x0c, 0x0c, 0x0c, 0xcc, 0xcc, 0x78 },
+    { 0xe0, 0x60, 0x66, 0x6c, 0x78, 0x6c, 0xe6, 0x00 },
+    { 0x70, 0x30, 0x30, 0x30, 0x30, 0x30, 0x78, 0x00 },
+    { 0x00, 0x00, 0xcc, 0xfe, 0xfe, 0xd6, 0xc6, 0x00 },
+    { 0x00, 0x00, 0xf8, 0xcc, 0xcc, 0xcc, 0xcc, 0x00 },
+    { 0x00, 0x00, 0x78, 0xcc, 0xcc, 0xcc, 0x78, 0x00 },
+    { 0x00, 0x00, 0xdc, 0x66, 0x66, 0x7c, 0x60, 0xf0 },
+    { 0x00, 0x00, 0x76, 0xcc, 0xcc, 0x7c, 0x0c, 0x1e },
+    { 0x00, 0x00, 0xdc, 0x76, 0x66, 0x60, 0xf0, 0x00 },
+    { 0x00, 0x00, 0x7c, 0xc0, 0x78, 0x0c, 0xf8, 0x00 },
+    { 0x10, 0x30, 0x7c, 0x30, 0x30, 0x34, 0x18, 0x00 },
+    { 0x00, 0x00, 0xcc, 0xcc, 0xcc, 0xcc, 0x76, 0x00 },
+    { 0x00, 0x00, 0xcc, 0xcc, 0xcc, 0x78, 0x30, 0x00 },
+    { 0x00, 0x00, 0xc6, 0xd6, 0xfe, 0xfe, 0x6c, 0x00 },
+    { 0x00, 0x00, 0xc6, 0x6c, 0x38, 0x6c, 0xc6, 0x00 },
+    { 0x00, 0x00, 0xcc, 0xcc, 0xcc, 0x7c, 0x0c, 0xf8 },
+    { 0x00, 0x00, 0xfc, 0x98, 0x30, 0x64, 0xfc, 0x00 },
+    { 0x1c, 0x30, 0x30, 0xe0, 0x30, 0x30, 0x1c, 0x00 },
+    { 0x18, 0x18, 0x18, 0x00, 0x18, 0x18, 0x18, 0x00 },
+    { 0xe0, 0x30, 0x30, 0x1c, 0x30, 0x30, 0xe0, 0x00 },
+    { 0x76, 0xdc, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
+    { 0x00, 0x10, 0x38, 0x6c, 0xc6, 0xc6, 0xfe, 0x00 },
+};
+
+#endif /* _FONT_H */
diff --git a/tr8vm.c b/tr8vm.c
index 59d08b7..7d254e0 100644
--- a/tr8vm.c
+++ b/tr8vm.c
@@ -30,7 +30,9 @@
 
 #include "vm.h"
 
-#define ARGB(r, g, b) ((uint32_t)(((r)<<16)|((g)<<8)|(b)))
+#include "font.h"
+
+#define ARGB(r, g, b) ((uint32_t)(0xff000000|((r)<<16)|((g)<<8)|(b)))
 
 #define APP_NAME "TR8 VM Player"
 #define APP_VERSION "0.1-alpha"
@@ -91,6 +93,47 @@ static uint32_t palette[] =
     ARGB(0xff, 0xff, 0xff),
 };
 
+uint32_t *ui_data = NULL;
+
+static void ui_put_glyph(uint32_t x, uint32_t y, uint8_t c)
+{
+    uint32_t *p = ui_data + x + (y * WINDOW_W);
+
+    for (uint8_t j = 0; j < 8; j++)
+        for (uint8_t i = 0; i < 8; i++)
+            if (font[c][j] & (128 >> i))
+                p[i + j * WINDOW_W] = palette[12];
+}
+
+static void ui_put_text(uint32_t x, uint32_t y, char *text)
+{
+    uint32_t ox = x;
+
+    while (*text)
+    {
+        uint8_t c = *text++;
+
+        if (c == '\n')
+        {
+            y += 12;
+            if (y > WINDOW_H)
+                break;
+
+            x = ox;
+            continue;
+        }
+
+        ui_put_glyph(x, y, c);
+
+        x += 8;
+        if (x > WINDOW_W)
+        {
+            x = 0;
+            y += 12;
+        }
+    }
+}
+
 uint8_t ram[UINT16_MAX + 1] = { 0 };
 uint32_t *fb_data = NULL;
 
@@ -234,6 +277,14 @@ int main(int argc, char *argv[])
     }
     SDL_SetTextureBlendMode(fb, SDL_BLENDMODE_NONE);
 
+    SDL_Texture *ui = SDL_CreateTexture(renderer, SDL_PIXELFORMAT_ARGB8888, SDL_TEXTUREACCESS_STREAMING, WINDOW_W, WINDOW_H);
+    if (!ui)
+    {
+        fprintf(stderr, "Failed to create the UI: %s\n", SDL_GetError());
+        return 1;
+    }
+    SDL_SetTextureBlendMode(ui, SDL_BLENDMODE_BLEND);
+
     int fullscreen = 0;
     SDL_Rect dst;
     resize_full_screen(screen, renderer, fullscreen, &dst);
@@ -244,7 +295,7 @@ int main(int argc, char *argv[])
     Tr8 vm;
     tr8_init(&vm, write_m, read_m, port);
     int pitch = 0;
-    uint8_t rc;
+    uint8_t rc = 1;
 
     /* update full fb once to sync with RAM */
     pitch = 0;
@@ -253,6 +304,13 @@ int main(int argc, char *argv[])
     update_fb();
     SDL_UnlockTexture(fb);
 
+    /* prepare UI layer */
+    pitch = 0;
+    ui_data = NULL;
+    SDL_LockTexture(ui, NULL, (void **)&ui_data, &pitch);
+    memset(ui_data, 0x20202080, sizeof(uint32_t) * WINDOW_W * WINDOW_H);
+    SDL_UnlockTexture(ui);
+
     SDL_Event ev;
     while (1)
     {
@@ -278,14 +336,29 @@ int main(int argc, char *argv[])
             }
         }
 
-        pitch = 0;
-        fb_data = NULL;
-        SDL_LockTexture(fb, NULL, (void **)&fb_data, &pitch);
-        rc = tr8_eval(&vm);
-        SDL_UnlockTexture(fb);
+        if (rc)
+        {
+            pitch = 0;
+            fb_data = NULL;
+            SDL_LockTexture(fb, NULL, (void **)&fb_data, &pitch);
+            rc = tr8_eval(&vm);
+            SDL_UnlockTexture(fb);
 
-        if (!rc)
-            break;
+            if (!rc)
+            {
+                /* non recoverable error */
+                pitch = 0;
+                ui_data = NULL;
+                SDL_LockTexture(ui, NULL, (void **)&ui_data, &pitch);
+                ui_put_text(10, 10, "[VM HALT]");
+
+                char buffer[256];
+                tr8_dump(&vm, buffer);
+                ui_put_text(10, 22, buffer);
+
+                SDL_UnlockTexture(ui);
+            }
+        }
 
         /* render to the canvas */
         SDL_SetRenderTarget(renderer, canvas);
@@ -298,16 +371,34 @@ int main(int argc, char *argv[])
         SDL_RenderClear(renderer);
         SDL_RenderCopy(renderer, canvas, NULL, &dst);
 
+        if (!rc)
+            SDL_RenderCopy(renderer, ui, NULL, &dst);
+
         SDL_RenderPresent(renderer);
 
-        pitch = 0;
-        fb_data = NULL;
-        SDL_LockTexture(fb, NULL, (void **)&fb_data, &pitch);
-        rc = tr8_frame_int(&vm);
-        SDL_UnlockTexture(fb);
+        if (rc)
+        {
+            pitch = 0;
+            fb_data = NULL;
+            SDL_LockTexture(fb, NULL, (void **)&ui_data, &pitch);
+            rc = tr8_frame_int(&vm);
+            SDL_UnlockTexture(fb);
 
-        if (!rc)
-            break;
+            if (!rc)
+            {
+                /* non recoverable error */
+                pitch = 0;
+                ui_data = NULL;
+                SDL_LockTexture(ui, NULL, (void **)&fb_data, &pitch);
+                ui_put_text(10, 10, "[VM HALT]");
+
+                char buffer[256];
+                tr8_dump(&vm, buffer);
+                ui_put_text(10, 22, buffer);
+
+                SDL_UnlockTexture(ui);
+            }
+        }
     }
 
     if (canvas)
diff --git a/vm.c b/vm.c
index 5f4b1ce..ff6bcb8 100644
--- a/vm.c
+++ b/vm.c
@@ -69,42 +69,49 @@ static uint8_t flags(uint8_t *f, uint16_t v, uint8_t mask)
     return v;
 }
 
-static void dump(Tr8 *vm)
+void tr8_dump(Tr8 *vm, char *buffer)
 {
     uint8_t i;
+    size_t s;
 
-    fprintf(stderr, "  PC 0x%04x: ", vm->pc);
-    for (i = 0; i < 16 && i + vm->pc < UINT16_MAX + 1; i++)
-        fprintf(stderr, "0x%02x ", vm->read_m(vm->pc + i));
-    fprintf(stderr, "\n");
+    s = sprintf(buffer, "  PC 0x%04x: ", vm->pc);
+    for (i = 0; i < 8 && i + vm->pc < UINT16_MAX + 1; i++)
+        s += sprintf(buffer + s, "0x%02x ", vm->read_m(vm->pc + i));
+    s += sprintf(buffer + s, "\n");
 
-    fprintf(stderr, "  SP 0x%04x: ", vm->sp);
+    s += sprintf(buffer + s, "  SP 0x%04x: ", vm->sp);
     if (vm->sp == vm->ssp)
-        fprintf(stderr, "-");
+        s += sprintf(buffer + s, "-");
     else
     {
-        for (i = 0; i < 16 && i + vm->sp < UINT16_MAX + 1; i++)
-            fprintf(stderr, "0x%02x ", vm->read_m(vm->sp + i));
+        for (i = 0; i < 8 && i + vm->sp < UINT16_MAX + 1; i++)
+            s += sprintf(buffer + s, "0x%02x ", vm->read_m(vm->sp + i));
     }
-    fprintf(stderr, "\n");
-
-    fprintf(stderr, "  F: %c%c%c%c%c%c\n"
-            "  A: 0x%02x B: 0x%02x\n"
-            "  X: 0x%02x Y: 0x%02x\n\n"
-            "  %d instr run\n",
-            (vm->f & ZF) ? 'Z' : 'z',
-            (vm->f & CF) ? 'C' : 'c',
-            (vm->f & OF) ? 'O' : 'o',
-            (vm->f & SF) ? 'S' : 's',
-            (vm->f & IF) ? 'I' : 'i',
-            (vm->f & BF) ? 'B' : 'b',
-            vm->regs[0],
-            vm->regs[1],
-            vm->regs[2],
-            vm->regs[3],
-            vm->icnt);
-
-    fprintf(stderr, "****\n");
+    s += sprintf(buffer + s, "\n");
+
+    s += sprintf(buffer + s, "  F: %c%c%c%c%c%c\n"
+                 "  A: 0x%02x B: 0x%02x\n"
+                 "  X: 0x%02x Y: 0x%02x\n\n"
+                 "  %d instr run\n",
+                 (vm->f & ZF) ? 'Z' : 'z',
+                 (vm->f & CF) ? 'C' : 'c',
+                 (vm->f & OF) ? 'O' : 'o',
+                 (vm->f & SF) ? 'S' : 's',
+                 (vm->f & IF) ? 'I' : 'i',
+                 (vm->f & BF) ? 'B' : 'b',
+                 vm->regs[0],
+                 vm->regs[1],
+                 vm->regs[2],
+                 vm->regs[3],
+                 vm->icnt);
+}
+
+static void dump(Tr8 *vm)
+{
+    char buffer[256];
+
+    tr8_dump(vm, buffer);
+    fputs(buffer, stderr);
 }
 
 void tr8_init(Tr8 *vm, void (*write_m)(uint16_t, uint8_t), uint8_t (*read_m)(uint16_t), uint8_t (*port)(uint8_t, uint8_t))
diff --git a/vm.h b/vm.h
index 118ea25..f66f8c9 100644
--- a/vm.h
+++ b/vm.h
@@ -45,5 +45,6 @@ typedef struct
 void tr8_init(Tr8 *vm, void (*write_m)(uint16_t, uint8_t), uint8_t (*read_m)(uint16_t), uint8_t (*port)(uint8_t, uint8_t));
 uint8_t tr8_eval(Tr8 *vm);
 uint8_t tr8_frame_int(Tr8 *vm);
+void tr8_dump(Tr8 *vm, char *buffer);
 
 #endif /* _TR8_H */