diff --git a/src/context.h b/src/context.h
new file mode 100644
index 0000000..48af06f
--- /dev/null
+++ b/src/context.h
@@ -0,0 +1,34 @@
+#ifndef _CONTEXT_H
+#define _CONTEXT_H
+
+#include "types.h"
+#include "reg.h"
+#include "stack.h"
+#include "mem.h"
+
+/*
+  Task/VM context
+*/
+typedef struct context {
+  index_t index;
+  stack_t *DS;
+  stack_t *FS;
+  reg_t   *R;
+  mem_t   *M;
+  segment_t *S;
+  index_t task;   // task number
+  int32_t evmask; // events of this task
+  struct context *next;  // task context chaining
+} context_t;
+
+extern context_t *Context[MAXTASKS];
+extern int       ContextTop;
+
+context_t *ContextAllocate();
+context_t* ContextInit(context_t* C, mem_t *M,stack_t *DS, stack_t *FS, reg_t *R);
+int        ContextReset(context_t *c);
+void       ContextResetAll(context_t *c0);
+
+#define CONTEXTID(C) (C->index)
+
+#endif