diff --git a/src/x86/msr.c b/src/x86/msr.c
index c11aa91..9736007 100644
--- a/src/x86/msr.c
+++ b/src/x86/msr.c
@@ -4,8 +4,8 @@ void read_msr(enum msr_id_t msr_addr, uint64_t *value)
 {
     uint64_t v;
     asm volatile("rdmsr"
-        : "=edx:eax" (v)
-        : "ecx" (msr_addr));
+        : "=A" (v)
+        : "c" (msr_addr));
     *value = v;
 }
 
@@ -13,5 +13,5 @@ void write_msr(enum msr_id_t msr_addr, uint64_t *value)
 {
     uint64_t v = *value;
     asm volatile("wrmsr"
-        :: "ecx"(msr_addr), "A"(v));
+        :: "c"(msr_addr), "A"(v));
 }