diff --git a/dlls/ntdll/signal_x86_64.c b/dlls/ntdll/signal_x86_64.c
index dd8dad9423a..c1210e9db0e 100644
--- a/dlls/ntdll/signal_x86_64.c
+++ b/dlls/ntdll/signal_x86_64.c
@@ -40,6 +40,7 @@
 #endif
 
 #define NONAMELESSUNION
+#define NONAMELESSSTRUCT
 #include "ntstatus.h"
 #define WIN32_NO_STATUS
 #include "windef.h"
@@ -157,6 +158,149 @@ typedef int (*wine_signal_handler)(unsigned int sig);
 
 static wine_signal_handler handlers[256];
 
+/* definitions for unwind tables */
+
+union handler_data
+{
+    RUNTIME_FUNCTION chain;
+    ULONG handler;
+};
+
+struct opcode
+{
+    BYTE offset;
+    BYTE code : 4;
+    BYTE info : 4;
+};
+
+struct UNWIND_INFO
+{
+    BYTE version : 3;
+    BYTE flags : 5;
+    BYTE prolog;
+    BYTE count;
+    BYTE frame_reg : 4;
+    BYTE frame_offset : 4;
+    struct opcode opcodes[1];  /* info->count entries */
+    /* followed by handler_data */
+};
+
+#define UWOP_PUSH_NONVOL     0
+#define UWOP_ALLOC_LARGE     1
+#define UWOP_ALLOC_SMALL     2
+#define UWOP_SET_FPREG       3
+#define UWOP_SAVE_NONVOL     4
+#define UWOP_SAVE_NONVOL_FAR 5
+#define UWOP_SAVE_XMM128     8
+#define UWOP_SAVE_XMM128_FAR 9
+#define UWOP_PUSH_MACHFRAME  10
+
+static void dump_unwind_info( ULONG64 base, RUNTIME_FUNCTION *function )
+{
+    static const char * const reg_names[16] =
+        { "rax", "rcx", "rdx", "rbx", "rsp", "rbp", "rsi", "rdi",
+          "r8",  "r9",  "r10", "r11", "r12", "r13", "r14", "r15" };
+
+    union handler_data *handler_data;
+    struct UNWIND_INFO *info;
+    unsigned int i, count;
+
+    TRACE( "**** func %x-%x\n", function->BeginAddress, function->EndAddress );
+    for (;;)
+    {
+        if (function->UnwindData & 1)
+        {
+            RUNTIME_FUNCTION *next = (RUNTIME_FUNCTION *)((char *)base + (function->UnwindData & ~1));
+            TRACE( "unwind info for function %p-%p chained to function %p-%p\n",
+                   (char *)base + function->BeginAddress, (char *)base + function->EndAddress,
+                   (char *)base + next->BeginAddress, (char *)base + next->EndAddress );
+            function = next;
+            continue;
+        }
+        info = (struct UNWIND_INFO *)((char *)base + function->UnwindData);
+
+        TRACE( "unwind info at %p flags %x prolog 0x%x bytes function %p-%p\n",
+               info, info->flags, info->prolog,
+               (char *)base + function->BeginAddress, (char *)base + function->EndAddress );
+
+        if (info->frame_reg)
+            TRACE( "    frame register %s offset 0x%x(%%rsp)\n",
+                   reg_names[info->frame_reg], info->frame_offset * 16 );
+
+        for (i = 0; i < info->count; i++)
+        {
+            TRACE( "    0x%x: ", info->opcodes[i].offset );
+            switch (info->opcodes[i].code)
+            {
+            case UWOP_PUSH_NONVOL:
+                TRACE( "pushq %%%s\n", reg_names[info->opcodes[i].info] );
+                break;
+            case UWOP_ALLOC_LARGE:
+                if (info->opcodes[i].info)
+                {
+                    count = *(DWORD *)&info->opcodes[i+1];
+                    i += 2;
+                }
+                else
+                {
+                    count = *(USHORT *)&info->opcodes[i+1] * 8;
+                    i++;
+                }
+                TRACE( "subq $0x%x,%%rsp\n", count );
+                break;
+            case UWOP_ALLOC_SMALL:
+                count = (info->opcodes[i].info + 1) * 8;
+                TRACE( "subq $0x%x,%%rsp\n", count );
+                break;
+            case UWOP_SET_FPREG:
+                TRACE( "leaq 0x%x(%%rsp),%s\n",
+                     info->frame_offset * 16, reg_names[info->frame_reg] );
+                break;
+            case UWOP_SAVE_NONVOL:
+                count = *(USHORT *)&info->opcodes[i+1] * 8;
+                TRACE( "movq %%%s,0x%x(%%rsp)\n", reg_names[info->opcodes[i].info], count );
+                i++;
+                break;
+            case UWOP_SAVE_NONVOL_FAR:
+                count = *(DWORD *)&info->opcodes[i+1];
+                TRACE( "movq %%%s,0x%x(%%rsp)\n", reg_names[info->opcodes[i].info], count );
+                i += 2;
+                break;
+            case UWOP_SAVE_XMM128:
+                count = *(USHORT *)&info->opcodes[i+1] * 16;
+                TRACE( "movaps %%xmm%u,0x%x(%%rsp)\n", info->opcodes[i].info, count );
+                i++;
+                break;
+            case UWOP_SAVE_XMM128_FAR:
+                count = *(DWORD *)&info->opcodes[i+1];
+                TRACE( "movaps %%xmm%u,0x%x(%%rsp)\n", info->opcodes[i].info, count );
+                i += 2;
+                break;
+            case UWOP_PUSH_MACHFRAME:
+                TRACE( "PUSH_MACHFRAME %u\n", info->opcodes[i].info );
+                break;
+            default:
+                FIXME( "unknown code %u\n", info->opcodes[i].code );
+                break;
+            }
+        }
+
+        handler_data = (union handler_data *)&info->opcodes[(info->count + 1) & ~1];
+        if (info->flags & UNW_FLAG_CHAININFO)
+        {
+            TRACE( "    chained to function %p-%p\n",
+                   (char *)base + handler_data->chain.BeginAddress,
+                   (char *)base + handler_data->chain.EndAddress );
+            function = &handler_data->chain;
+            continue;
+        }
+        if (info->flags & (UNW_FLAG_EHANDLER | UNW_FLAG_UHANDLER))
+            TRACE( "    handler %p data at %p\n",
+                   (char *)base + handler_data->handler, &handler_data->handler + 1 );
+        break;
+    }
+}
+
 /***********************************************************************
  *           dispatch_signal
  */
@@ -882,17 +1026,142 @@ PRUNTIME_FUNCTION WINAPI RtlLookupFunctionEntry( ULONG64 pc, ULONG64 *base,
     return NULL;
 }
 
+static ULONG64 get_int_reg( CONTEXT *context, int reg )
+{
+    return *(&context->Rax + reg);
+}
+
+static void set_int_reg( CONTEXT *context, KNONVOLATILE_CONTEXT_POINTERS *ctx_ptr, int reg, ULONG64 val )
+{
+    *(&context->Rax + reg) = val;
+    if (ctx_ptr) ctx_ptr->u2.IntegerContext[reg] = &context->Rax + reg;
+}
+
+static void set_float_reg( CONTEXT *context, KNONVOLATILE_CONTEXT_POINTERS *ctx_ptr, int reg, M128A val )
+{
+    *(&context->u.s.Xmm0 + reg) = val;
+    if (ctx_ptr) ctx_ptr->u1.FloatingContext[reg] = &context->u.s.Xmm0 + reg;
+}
+
+static int get_opcode_size( struct opcode op )
+{
+    switch (op.code)
+    {
+    case UWOP_ALLOC_LARGE:
+        return 2 + (op.info != 0);
+    case UWOP_SAVE_NONVOL:
+    case UWOP_SAVE_XMM128:
+        return 2;
+    case UWOP_SAVE_NONVOL_FAR:
+    case UWOP_SAVE_XMM128_FAR:
+        return 3;
+    default:
+        return 1;
+    }
+}
 
 /**********************************************************************
  *              RtlVirtualUnwind   (NTDLL.@)
  */
-PVOID WINAPI RtlVirtualUnwind ( ULONG type, ULONG64 base, ULONG64 pc,
-                                RUNTIME_FUNCTION *function, CONTEXT *context,
-                                PVOID *data, ULONG64 *frame,
-                                KNONVOLATILE_CONTEXT_POINTERS *ctx_ptr )
+PVOID WINAPI RtlVirtualUnwind( ULONG type, ULONG64 base, ULONG64 pc,
+                               RUNTIME_FUNCTION *function, CONTEXT *context,
+                               PVOID *data, ULONG64 *frame_ret,
+                               KNONVOLATILE_CONTEXT_POINTERS *ctx_ptr )
 {
-    FIXME("stub\n");
-    return NULL;
+    union handler_data *handler_data;
+    ULONG64 frame, off;
+    struct UNWIND_INFO *info;
+    unsigned int i, prolog_offset;
+
+    TRACE( "type %x rip %lx rsp %lx\n", type, pc, context->Rsp );
+
+    dump_unwind_info( base, function );
+
+    frame = context->Rsp;
+    for (;;)
+    {
+        info = (struct UNWIND_INFO *)((char *)base + function->UnwindData);
+        handler_data = (union handler_data *)&info->opcodes[(info->count + 1) & ~1];
+
+        if (info->version != 1)
+        {
+            FIXME( "unknown unwind info version %u at %p\n", info->version, info );
+            return NULL;
+        }
+
+        if (info->frame_reg)
+            frame = get_int_reg( context, info->frame_reg ) - info->frame_offset * 16;
+
+        /* check if in prolog */
+        if (pc >= base + function->BeginAddress && pc < base + function->BeginAddress + info->prolog)
+        {
+            prolog_offset = pc - base - function->BeginAddress;
+        }
+        else
+        {
+            prolog_offset = ~0;
+            /* FIXME: check for function epilog */
+        }
+
+        for (i = 0; i < info->count; i += get_opcode_size(info->opcodes[i]))
+        {
+            if (prolog_offset < info->opcodes[i].offset) continue; /* skip it */
+
+            switch (info->opcodes[i].code)
+            {
+            case UWOP_PUSH_NONVOL:  /* pushq %reg */
+                set_int_reg( context, ctx_ptr, info->opcodes[i].info, *(ULONG64 *)context->Rsp );
+                context->Rsp += sizeof(ULONG64);
+                break;
+            case UWOP_ALLOC_LARGE:  /* subq $nn,%rsp */
+                if (info->opcodes[i].info) context->Rsp += *(DWORD *)&info->opcodes[i+1];
+                else context->Rsp += *(USHORT *)&info->opcodes[i+1] * 8;
+                break;
+            case UWOP_ALLOC_SMALL:  /* subq $n,%rsp */
+                context->Rsp += (info->opcodes[i].info + 1) * 8;
+                break;
+            case UWOP_SET_FPREG:  /* leaq nn(%rsp),%framereg */
+                context->Rsp = frame;
+                break;
+            case UWOP_SAVE_NONVOL:  /* movq %reg,n(%rsp) */
+                off = frame + *(USHORT *)&info->opcodes[i+1] * 8;
+                set_int_reg( context, ctx_ptr, info->opcodes[i].info, *(ULONG64 *)off );
+                break;
+            case UWOP_SAVE_NONVOL_FAR:  /* movq %reg,nn(%rsp) */
+                off = frame + *(DWORD *)&info->opcodes[i+1];
+                set_int_reg( context, ctx_ptr, info->opcodes[i].info, *(ULONG64 *)off );
+                break;
+            case UWOP_SAVE_XMM128:  /* movaps %xmmreg,n(%rsp) */
+                off = frame + *(USHORT *)&info->opcodes[i+1] * 16;
+                set_float_reg( context, ctx_ptr, info->opcodes[i].info, *(M128A *)off );
+                break;
+            case UWOP_SAVE_XMM128_FAR:  /* movaps %xmmreg,nn(%rsp) */
+                off = frame + *(DWORD *)&info->opcodes[i+1];
+                set_float_reg( context, ctx_ptr, info->opcodes[i].info, *(M128A *)off );
+                break;
+            case UWOP_PUSH_MACHFRAME:
+                FIXME( "PUSH_MACHFRAME %u\n", info->opcodes[i].info );
+                break;
+            default:
+                FIXME( "unknown code %u\n", info->opcodes[i].code );
+                break;
+            }
+        }
+
+        if (!(info->flags & UNW_FLAG_CHAININFO)) break;
+        function = &handler_data->chain;  /* restart with the chained info */
+    }
+
+    /* now pop return address */
+    context->Rip = *(ULONG64 *)context->Rsp;
+    context->Rsp += sizeof(ULONG64);
+    *frame_ret = frame;
+
+    if (!(info->flags & type)) return NULL;  /* no matching handler */
+    if (prolog_offset != ~0) return NULL;  /* inside prolog */
+
+    *data = &handler_data->handler + 1;
+    return (char *)base + handler_data->handler;
 }
 
 
diff --git a/include/winternl.h b/include/winternl.h
index b06a10c3745..b386787218d 100644
--- a/include/winternl.h
+++ b/include/winternl.h
@@ -994,6 +994,11 @@ typedef struct _KNONVOLATILE_CONTEXT_POINTERS
 
 PVOID WINAPI RtlVirtualUnwind(ULONG,ULONG64,ULONG64,RUNTIME_FUNCTION*,CONTEXT*,PVOID*,ULONG64*,KNONVOLATILE_CONTEXT_POINTERS*);
 
+#define UNW_FLAG_NHANDLER  0
+#define UNW_FLAG_EHANDLER  1
+#define UNW_FLAG_UHANDLER  2
+#define UNW_FLAG_CHAININFO 4
+
 #endif  /* __x86_64 */