diff --git a/py/asmx86.c b/py/asmx86.c
index 23160c9c20..e4736251f8 100644
--- a/py/asmx86.c
+++ b/py/asmx86.c
@@ -403,7 +403,7 @@ void asm_x86_entry(asm_x86_t *as, int num_locals) {
     asm_x86_push_r32(as, ASM_X86_REG_EBX);
     asm_x86_push_r32(as, ASM_X86_REG_ESI);
     asm_x86_push_r32(as, ASM_X86_REG_EDI);
-    num_locals |= 1; // make it odd so stack is aligned on 16 byte boundary
+    num_locals |= 3; // make it odd so stack is aligned on 16 byte boundary
     asm_x86_sub_r32_i32(as, ASM_X86_REG_ESP, num_locals * WORD_SIZE);
     as->num_locals = num_locals;
 }
@@ -497,8 +497,14 @@ void asm_x86_push_local_addr(asm_x86_t *as, int local_num, int temp_r32)
 #endif
 
 void asm_x86_call_ind(asm_x86_t *as, size_t fun_id, mp_uint_t n_args, int temp_r32) {
-    // TODO align stack on 16-byte boundary before the call
     assert(n_args <= 5);
+
+    // Align stack on 16-byte boundary during the call
+    unsigned int align = ((n_args + 3) & ~3) - n_args;
+    if (align) {
+        asm_x86_sub_r32_i32(as, ASM_X86_REG_ESP, align * WORD_SIZE);
+    }
+
     if (n_args > 4) {
         asm_x86_push_r32(as, ASM_X86_REG_ARG_5);
     }
@@ -521,7 +527,7 @@ void asm_x86_call_ind(asm_x86_t *as, size_t fun_id, mp_uint_t n_args, int temp_r
 
     // the caller must clean up the stack
     if (n_args > 0) {
-        asm_x86_add_i32_to_r32(as, WORD_SIZE * n_args, ASM_X86_REG_ESP);
+        asm_x86_add_i32_to_r32(as, (n_args + align) * WORD_SIZE, ASM_X86_REG_ESP);
     }
 }