diff --git a/library/aes.c b/library/aes.c
index 4cb9ce1c14..ebacc671a4 100644
--- a/library/aes.c
+++ b/library/aes.c
@@ -40,15 +40,16 @@
 #endif
 #endif
 
-#if defined(__amd64__) || defined(__x86_64__)
+#if defined(__amd64__) || defined(__x86_64__) || \
+    defined(_M_X64) || defined(_M_AMD64)
 #if !defined(MBEDTLS_AESNI_C) && defined(MBEDTLS_AES_USE_HARDWARE_ONLY)
 #error "MBEDTLS_AES_USE_HARDWARE_ONLY defined, but not all prerequisites"
 #endif
 #endif
 
-#if defined(__i386__)
-#if defined(MBEDTLS_AES_USE_HARDWARE_ONLY)
-#error "MBEDTLS_AES_USE_HARDWARE_ONLY not supported yet for i386."
+#if defined(__i386__) || defined(_M_IX86)
+#if defined(MBEDTLS_AES_USE_HARDWARE_ONLY) && !defined(MBEDTLS_AESNI_C)
+#error "MBEDTLS_AES_USE_HARDWARE_ONLY defined, but not all prerequisites"
 #endif
 
 #if defined(MBEDTLS_PADLOCK_C) && !defined(MBEDTLS_HAVE_ASM)
diff --git a/library/aesni.h b/library/aesni.h
index dc6444270a..1cf01ec9e8 100644
--- a/library/aesni.h
+++ b/library/aesni.h
@@ -41,7 +41,13 @@
 #define MBEDTLS_HAVE_X86_64
 #endif
 
-#if defined(MBEDTLS_AESNI_C) && defined(MBEDTLS_HAVE_X86_64)
+#if !defined(MBEDTLS_HAVE_X86) && \
+    (defined(__i386__) || defined(_M_IX86))
+#define MBEDTLS_HAVE_X86
+#endif
+
+#if defined(MBEDTLS_AESNI_C) && \
+    (defined(MBEDTLS_HAVE_X86_64) || defined(MBEDTLS_HAVE_X86))
 
 /* Can we do AESNI with intrinsics?
  * (Only implemented with certain compilers, only for certain targets.)
@@ -67,7 +73,8 @@
  * In the long run, we will likely remove the assembly implementation. */
 #if defined(MBEDTLS_AESNI_HAVE_INTRINSICS)
 #define MBEDTLS_AESNI_HAVE_CODE 2 // via intrinsics
-#elif defined(MBEDTLS_HAVE_ASM) && defined(__GNUC__)
+#elif defined(MBEDTLS_HAVE_ASM) && \
+    defined(__GNUC__) && defined(MBEDTLS_HAVE_X86_64)
 #define MBEDTLS_AESNI_HAVE_CODE 1 // via assembly
 #else
 #error "MBEDTLS_AESNI_C defined, but neither intrinsics nor assembly available"