diff --git a/src/emu/x64runf30f.c b/src/emu/x64runf30f.c
index 3a99ebf631..cc678f853b 100644
--- a/src/emu/x64runf30f.c
+++ b/src/emu/x64runf30f.c
@@ -552,19 +552,20 @@ uintptr_t RunF30F(x64emu_t *emu, rex_t rex, uintptr_t addr, int* step)
         GX->ud[0]=(tmp8s)?0xffffffff:0;
         break;
 
-    case 0xC7:  
-        CHECK_FLAGS(emu);
-        nextop = F8;
-        GETE8xw(0);
-        switch(tmp8u&7) {
-            case 6: /* RDPID Ed */
-                ED->q[0] = helper_getcpu(emu);
-                SET_FLAG(F_CF);
-                break;
-            default:
-                return 0;
-        }
-        GX->ud[0]=(tmp8s)?0xffffffff:0;
+    case 0xC7:
+        nextop = F8;
+        tmp8u = nextop >> 3;
+        switch(tmp8u&7) {
+            case 7: /* RDPID Ed */
+                if (!MODREG) {
+                    return 0;
+                }
+                GETED(0);
+                ED->q[0] = helper_getcpu(emu);
+                break;
+            default:
+                return 0;
+        }
         break;
 
         case 0xD6:  /* MOVQ2DQ Gx, Em */
diff --git a/src/emu/x64tls.c b/src/emu/x64tls.c
index a427186ebe..6ebe541b70 100644
--- a/src/emu/x64tls.c
+++ b/src/emu/x64tls.c
@@ -137,7 +137,7 @@ uint32_t my_modify_ldt(x64emu_t* emu, int op, thread_area_32_t* td, int size)
 
 static const char* arch_prctl_param(int code)
 {
-    static char ret[10] = {0};
+    static char ret[12] = {0};
     switch (code) {
         case 0x1001: return "ARCH_SET_GS";
         case 0x1002: return "ARCH_SET_FS";