diff --git a/remill/Arch/X86/Semantics/MMX.cpp b/remill/Arch/X86/Semantics/MMX.cpp
index 9d96ffda..a09418a9 100644
--- a/remill/Arch/X86/Semantics/MMX.cpp
+++ b/remill/Arch/X86/Semantics/MMX.cpp
@@ -1763,10 +1763,11 @@ DEF_SEM(PSHUFB, D dst, S1 src1, S2 src2) {
   auto dst_vec = UClearV8(UReadV8(dst));
 
   auto vec_count = NumVectorElems(src1_vec);
+  uint8_t mask = vec_count - 1;
   _Pragma("unroll")
   for (size_t i = 0; i < vec_count; i++) {
     uint8_t v1 = UExtractV8(src2_vec, i);
-    uint8_t index = UAnd(v1, 7_u8);
+    uint8_t index = UAnd(v1, mask);
     uint8_t v2 = UExtractV8(src1_vec, index);
     uint8_t value = Select(SignFlag(v1), 0_u8, v2);
     dst_vec = UInsertV8(dst_vec, i, value);
diff --git a/remill/Arch/X86/Semantics/SSE.cpp b/remill/Arch/X86/Semantics/SSE.cpp
index f599c823..cca8833f 100644
--- a/remill/Arch/X86/Semantics/SSE.cpp
+++ b/remill/Arch/X86/Semantics/SSE.cpp
@@ -325,8 +325,8 @@ DEF_SEM(PSHUFD, D dst, S1 src1, I8 src2) {
 
 DEF_ISEL(PSHUFD_XMMdq_MEMdq_IMMb) = PSHUFD<V128W, MV128>;
 DEF_ISEL(PSHUFD_XMMdq_XMMdq_IMMb) = PSHUFD<V128W, V128>;
-IF_AVX(DEF_ISEL(VPSHUFD_XMMdq_MEMdq_IMMb) = PSHUFD<V128W, MV128>;)
-IF_AVX(DEF_ISEL(VPSHUFD_XMMdq_XMMdq_IMMb) = PSHUFD<V128W, V128>;)
+IF_AVX(DEF_ISEL(VPSHUFD_XMMdq_MEMdq_IMMb) = PSHUFD<VV128W, MV128>;)
+IF_AVX(DEF_ISEL(VPSHUFD_XMMdq_XMMdq_IMMb) = PSHUFD<VV128W, V128>;)
 IF_AVX(DEF_ISEL(VPSHUFD_YMMqq_MEMqq_IMMb) = PSHUFD<VV256W, MV256>;)
 IF_AVX(DEF_ISEL(VPSHUFD_YMMqq_YMMqq_IMMb) = PSHUFD<VV256W, V256>;)