Index: docs/index.rst
===================================================================
--- docs/index.rst
+++ docs/index.rst
@@ -50,7 +50,7 @@
 Linux        ARM                  Clang, GCC   EHABI
 Bare Metal   ARM                  Clang, GCC   EHABI
 NetBSD       x86_64               Clang, GCC   DWARF CFI
-Windows      i386                 Clang        DWARF CFI
+Windows      i386, x86_64         Clang        DWARF CFI
 Any          i386, x86_64, ARM    Clang        SjLj
 ============ ==================== ============ ========================
 
Index: include/unwind.h
===================================================================
--- include/unwind.h
+++ include/unwind.h
@@ -122,7 +122,7 @@
                             _Unwind_Exception *exc);
   uintptr_t private_1; // non-zero means forced unwind
   uintptr_t private_2; // holds sp that phase1 found for phase2 to use
-#ifndef __LP64__
+#if !defined(__LP64__) && !defined(_WIN64)
   // The implementation of _Unwind_Exception uses an attribute mode on the
   // above fields which has the side effect of causing this whole struct to
   // round up to 32 bytes in size. To be more explicit, we add pad fields
Index: src/AddressSpace.hpp
===================================================================
--- src/AddressSpace.hpp
+++ src/AddressSpace.hpp
@@ -142,7 +142,7 @@
 /// making local unwinds fast.
 class __attribute__((visibility("hidden"))) LocalAddressSpace {
 public:
-#ifdef __LP64__
+#if defined(__LP64__) || defined(_WIN64)
   typedef uint64_t pint_t;
   typedef int64_t  sint_t;
 #else
@@ -194,7 +194,7 @@
 };
 
 inline uintptr_t LocalAddressSpace::getP(pint_t addr) {
-#ifdef __LP64__
+#if defined(__LP64__) || defined(_WIN64)
   return get64(addr);
 #else
   return get32(addr);
Index: src/UnwindLevel1.c
===================================================================
--- src/UnwindLevel1.c
+++ src/UnwindLevel1.c
@@ -86,7 +86,7 @@
     // this frame.
     if (frameInfo.handler != 0) {
       __personality_routine p =
-          (__personality_routine)(long)(frameInfo.handler);
+          (__personality_routine)(uintptr_t)(frameInfo.handler);
       _LIBUNWIND_TRACE_UNWINDING(
           "unwind_phase1(ex_ojb=%p): calling personality function %p",
           (void *)exception_object, (void *)(uintptr_t)p);
@@ -181,7 +181,7 @@
     // If there is a personality routine, tell it we are unwinding.
     if (frameInfo.handler != 0) {
       __personality_routine p =
-          (__personality_routine)(long)(frameInfo.handler);
+          (__personality_routine)(uintptr_t)(frameInfo.handler);
       _Unwind_Action action = _UA_CLEANUP_PHASE;
       if (sp == exception_object->private_2) {
         // Tell personality this was the frame it marked in phase 1.
Index: src/UnwindRegistersRestore.S
===================================================================
--- src/UnwindRegistersRestore.S
+++ src/UnwindRegistersRestore.S
@@ -65,6 +65,40 @@
 #
 # void libunwind::Registers_x86_64::jumpto()
 #
+#if defined(_WIN32)
+# On entry, thread_state pointer is in rcx
+
+  movq  56(%rcx), %rax # rax holds new stack pointer
+  subq  $16, %rax
+  movq  %rax, 56(%rcx)
+  movq  16(%rcx), %rdx  # store new rcx on new stack
+  movq  %rdx, 0(%rax)
+  movq  128(%rcx), %rdx # store new rip on new stack
+  movq  %rdx, 8(%rax)
+  # restore all registers
+  movq    0(%rcx), %rax
+  movq    8(%rcx), %rbx
+  # restore rcx later
+  movq   24(%rcx), %rdx
+  movq   32(%rcx), %rdi
+  movq   40(%rcx), %rsi
+  movq   48(%rcx), %rbp
+  # restore rsp later
+  movq   64(%rcx), %r8
+  movq   72(%rcx), %r9
+  movq   80(%rcx), %r10
+  movq   88(%rcx), %r11
+  movq   96(%rcx), %r12
+  movq  104(%rcx), %r13
+  movq  112(%rcx), %r14
+  movq  120(%rcx), %r15
+  # skip rflags
+  # skip cs
+  # skip fs
+  # skip gs
+  movq  56(%rcx), %rsp  # cut back rsp to new location
+  pop    %rcx      # rcx was saved here earlier
+#else
 # On entry, thread_state pointer is in rdi
 
   movq  56(%rdi), %rax # rax holds new stack pointer
@@ -97,6 +131,7 @@
   # skip gs
   movq  56(%rdi), %rsp  # cut back rsp to new location
   pop    %rdi      # rdi was saved here earlier
+#endif
   ret            # rip was saved here
 
 
Index: src/UnwindRegistersSave.S
===================================================================
--- src/UnwindRegistersSave.S
+++ src/UnwindRegistersSave.S
@@ -63,6 +63,27 @@
 #  thread_state pointer is in rdi
 #
 DEFINE_LIBUNWIND_FUNCTION(unw_getcontext)
+#if defined(_WIN32)
+  movq  %rax,   (%rcx)
+  movq  %rbx,  8(%rcx)
+  movq  %rcx, 16(%rcx)
+  movq  %rdx, 24(%rcx)
+  movq  %rdi, 32(%rcx)
+  movq  %rsi, 40(%rcx)
+  movq  %rbp, 48(%rcx)
+  movq  %rsp, 56(%rcx)
+  addq  $8,   56(%rcx)
+  movq  %r8,  64(%rcx)
+  movq  %r9,  72(%rcx)
+  movq  %r10, 80(%rcx)
+  movq  %r11, 88(%rcx)
+  movq  %r12, 96(%rcx)
+  movq  %r13,104(%rcx)
+  movq  %r14,112(%rcx)
+  movq  %r15,120(%rcx)
+  movq  (%rsp),%rdx
+  movq  %rdx,128(%rcx) # store return address as rip
+#else
   movq  %rax,   (%rdi)
   movq  %rbx,  8(%rdi)
   movq  %rcx, 16(%rdi)
@@ -82,6 +103,7 @@
   movq  %r15,120(%rdi)
   movq  (%rsp),%rsi
   movq  %rsi,128(%rdi) # store return address as rip
+#endif
   # skip rflags
   # skip cs
   # skip fs