diff --git a/src/coreclr/jit/codegen.h b/src/coreclr/jit/codegen.h
index 8676dd22aaff..1def454ab95e 100644
--- a/src/coreclr/jit/codegen.h
+++ b/src/coreclr/jit/codegen.h
@@ -522,9 +522,9 @@ class CodeGen final : public CodeGenInterface
 
     void genReserveProlog(BasicBlock* block); // currently unused
     void genReserveEpilog(BasicBlock* block);
-#if defined(TARGET_AMD64)
+#if defined(WINDOWS_AMD64_ABI)
     void genFnPreProlog();
-#endif // defined(TARGET_AMD64)
+#endif // defined(WINDOWS_AMD64_ABI)
     void genFnProlog();
     void genFnEpilog(BasicBlock* block);
 
diff --git a/src/coreclr/jit/codegencommon.cpp b/src/coreclr/jit/codegencommon.cpp
index be481b46b8f5..6b8ad1a7843f 100644
--- a/src/coreclr/jit/codegencommon.cpp
+++ b/src/coreclr/jit/codegencommon.cpp
@@ -5483,11 +5483,11 @@ void CodeGen::genFinalizeFrame()
  *  genFnPreProlog is optional (currently only on for x64 but eventually
  *  some frames will likely skip it).
  *
- *  Although currently only being used for TARGET_AMD64, this is eventually
+ *  Although currently only being used for WINDOWS_AMD64_ABI, this is eventually
  *  intended for all architectures, so it is not in codegenxarch.cpp.
  */
 
-#if defined(TARGET_AMD64)
+#if defined(WINDOWS_AMD64_ABI)
 void CodeGen::genFnPreProlog()
 {
     ScopedSetVariable<bool> _setGeneratingPreProlog(&compiler->compGeneratingPreProlog, true);
@@ -5545,7 +5545,7 @@ void CodeGen::genFnPreProlog()
 
     emit->emitEndPreProlog();
 }
-#endif // defined(TARGET_AMD64)
+#endif // defined(WINDOWS_AMD64_ABI)
 
 /*****************************************************************************
  *
diff --git a/src/coreclr/jit/emit.cpp b/src/coreclr/jit/emit.cpp
index 751525a3ba38..41d44bb470e0 100644
--- a/src/coreclr/jit/emit.cpp
+++ b/src/coreclr/jit/emit.cpp
@@ -1641,7 +1641,7 @@ void emitter::emitCheckIGoffsets()
 
 #endif // DEBUG
 
-#if defined(TARGET_AMD64)
+#if defined(WINDOWS_AMD64_ABI)
 
 void emitter::emitBegPreProlog()
 {
@@ -1666,27 +1666,13 @@ void emitter::emitBegPreProlog()
 
 int UnwindCodeNodeSize(UNWIND_CODE code)
 {
-    int unwindCodeNodeSize = 1;
-    switch (code.UnwindOp)
+    if (code.UnwindOp == UWOP_ALLOC_LARGE)
     {
-        case UWOP_ALLOC_LARGE:
-            if (code.OpInfo == 0)
-                unwindCodeNodeSize = 2;
-            else
-                unwindCodeNodeSize = 3;
-            break;
-
-        case UWOP_SAVE_XMM128:
-        case UWOP_SAVE_NONVOL:
-            unwindCodeNodeSize = 2;
-            break;
-
-        case UWOP_SAVE_NONVOL_FAR:
-        case UWOP_SAVE_XMM128_FAR:
-            unwindCodeNodeSize = 3;
-            break;
+        return (code.OpInfo == 0) ? 2 : 3;
     }
-    return unwindCodeNodeSize;
+
+    // Since table gives -extra- slots, we add one for the actual size
+    return UnwindOpExtraSlotTable[code.UnwindOp] + 1;
 }
 
 void emitter::emitEndPreProlog()
@@ -1697,12 +1683,12 @@ void emitter::emitEndPreProlog()
     FuncInfoDsc* func = emitComp->funCurrentFunc();
     assert(func->unwindHeader.CountOfUnwindCodes == 0); // Can't call this after unwindReserve
 
-    auto unwindCodeStart = (UNWIND_CODE*)&func->unwindCodes[func->unwindCodeSlot];
-    auto unwindCodeEnd = (UNWIND_CODE*)&func->unwindCodes[sizeof(func->unwindCodes)];
+    auto unwindCodeStart = reinterpret_cast<UNWIND_CODE*>(&func->unwindCodes[func->unwindCodeSlot]);
+    auto unwindCodeEnd = reinterpret_cast<UNWIND_CODE*>(&func->unwindCodes[sizeof(func->unwindCodes)]);
 
-    int unwindCodeNodeSize = 1;
     for (auto unwindCodeCurrent = unwindCodeStart; unwindCodeCurrent != unwindCodeEnd; unwindCodeCurrent += UnwindCodeNodeSize(*unwindCodeCurrent))
     {
+        assert(unwindCodeCurrent < unwindCodeEnd); // Avoid a corrupted size leading to overrun by skipping the end
         uint8_t oldCodeOffset = unwindCodeCurrent->CodeOffset;
         uint8_t newCodeOffset = (uint8_t)(oldCodeOffset + prePrologSize);
         assert(newCodeOffset > oldCodeOffset); // I'm not sure if we can overflow here, but an assert should help
@@ -1710,7 +1696,7 @@ void emitter::emitEndPreProlog()
     }
 }
 
-#endif // defined(TARGET_AMD64)
+#endif // defined(WINDOWS_AMD64_ABI)
 
 
 /*****************************************************************************
diff --git a/src/coreclr/jit/emitpub.h b/src/coreclr/jit/emitpub.h
index c6e9ca41d370..f2818b5f34da 100644
--- a/src/coreclr/jit/emitpub.h
+++ b/src/coreclr/jit/emitpub.h
@@ -43,10 +43,10 @@ unsigned emitGetEpilogCnt();
 template <typename Callback>
 bool emitGenNoGCLst(Callback& cb);
 
-#if defined(TARGET_AMD64)
+#if defined(WINDOWS_AMD64_ABI)
 void     emitBegPreProlog();
 void     emitEndPreProlog();
-#endif // defined(TARGET_AMD64)
+#endif // defined(WINDOWS_AMD64_ABI)
 void     emitBegProlog();
 unsigned emitGetPrologOffsetEstimate();
 void     emitMarkPrologEnd();