diff --git a/src/xenia/cpu/backend/a64/a64_backend.cc b/src/xenia/cpu/backend/a64/a64_backend.cc
index 076c1d487..d1780980b 100644
--- a/src/xenia/cpu/backend/a64/a64_backend.cc
+++ b/src/xenia/cpu/backend/a64/a64_backend.cc
@@ -418,7 +418,7 @@ void A64ThunkEmitter::EmitSaveVolatileRegs() {
   STR(X15, XSP, offsetof(StackLayout::Thunk, r[15]));
   STR(X16, XSP, offsetof(StackLayout::Thunk, r[16]));
   STR(X17, XSP, offsetof(StackLayout::Thunk, r[17]));
-  STR(X17, XSP, offsetof(StackLayout::Thunk, r[18]));
+  STR(X18, XSP, offsetof(StackLayout::Thunk, r[18]));
 
   STR(Q0, XSP, offsetof(StackLayout::Thunk, xmm[0]));
   STR(Q1, XSP, offsetof(StackLayout::Thunk, xmm[1]));
diff --git a/src/xenia/cpu/backend/a64/a64_stack_layout.h b/src/xenia/cpu/backend/a64/a64_stack_layout.h
index 87dc3379c..02db19db2 100644
--- a/src/xenia/cpu/backend/a64/a64_stack_layout.h
+++ b/src/xenia/cpu/backend/a64/a64_stack_layout.h
@@ -91,7 +91,7 @@ class StackLayout {
   XEPACKEDSTRUCT(Thunk, {
     uint64_t arg_temp[3];
     uint64_t r[19];
-    vec128_t xmm[31];
+    vec128_t xmm[32];
   });
   static_assert(sizeof(Thunk) % 16 == 0,
                 "sizeof(Thunk) must be a multiple of 16!");