diff --git a/efiemu/runtime/efiemu.c b/efiemu/runtime/efiemu.c
index 5887c48..f73f843 100644
--- a/efiemu/runtime/efiemu.c
+++ b/efiemu/runtime/efiemu.c
@@ -162,8 +162,8 @@ static inline void
 write_cmos (grub_uint8_t addr, grub_uint8_t val)
 {
   __asm__ __volatile__ ("outb %%al,$0x70\n"
-			"mov %%bl, %%al\n"
-			"outb %%al,$0x71": :"a" (addr), "b" (val));
+			"mov %%cl, %%al\n"
+			"outb %%al,$0x71": :"a" (addr), "c" (val));
 }
 
 static inline grub_uint8_t
diff --git a/include/grub/i386/tsc.h b/include/grub/i386/tsc.h
index 9633701..aa40145 100644
--- a/include/grub/i386/tsc.h
+++ b/include/grub/i386/tsc.h
@@ -29,8 +29,24 @@ grub_get_tsc (void)
 
   /* The CPUID instruction is a 'serializing' instruction, and
      avoids out-of-order execution of the RDTSC instruction. */
+#ifdef APPLE_CC
   __asm__ __volatile__ ("xorl %%eax, %%eax\n\t"
-                        "cpuid":::"%rax", "%rbx", "%rcx", "%rdx");
+#ifdef __x86_64__
+			"push %%rbx\n"
+#else
+			"push %%ebx\n"
+#endif
+			"cpuid\n"
+#ifdef __x86_64__
+			"pop %%rbx\n"
+#else
+			"pop %%ebx\n"
+#endif	
+			:::"%rax", "%rcx", "%rdx");
+#else
+  __asm__ __volatile__ ("xorl %%eax, %%eax\n\t"
+			"cpuid":::"%rax", "%rbx", "%rcx", "%rdx");
+#endif
   /* Read TSC value.  We cannot use "=A", since this would use
      %rax on x86_64. */
   __asm__ __volatile__ ("rdtsc":"=a" (lo), "=d" (hi));
@@ -93,11 +109,29 @@ grub_cpu_is_tsc_supported (void)
     return 0;
 
   grub_uint32_t features;
+#ifdef APPLE_CC
   __asm__ ("movl $1, %%eax\n\t"
-           "cpuid"
+#ifdef __x86_64__
+	   "push %%rbx\n"
+#else
+	   "push %%ebx\n"
+#endif
+	   "cpuid\n"
+#ifdef __x86_64__
+	   "pop %%rbx\n"
+#else
+	   "pop %%ebx\n"
+#endif
+           : "=d" (features)
+           : /* No inputs.  */
+	   : /* Clobbered:  */ "%rax", "%rcx");
+#else
+  __asm__ ("movl $1, %%eax\n\t"
+           "cpuid\n"
            : "=d" (features)
            : /* No inputs.  */
            : /* Clobbered:  */ "%rax", "%rbx", "%rcx");
+#endif
   return (features & (1 << 4)) != 0;
 }
 
diff --git a/loader/i386/xnu.c b/loader/i386/xnu.c
index 0860160..2fb490d 100644
--- a/loader/i386/xnu.c
+++ b/loader/i386/xnu.c
@@ -125,6 +125,28 @@ guessfsb (void)
 
   if (! grub_cpu_is_cpuid_supported ())
     return sane_value;
+	
+#ifdef APPLE_CC
+  asm volatile ("movl $0, %%eax\n"
+#ifdef __x86_64__
+		"push %%rbx\n"
+#else
+		"push %%ebx\n"
+#endif
+		"cpuid\n"
+#ifdef __x86_64__
+		"pop %%rbx\n"
+#else
+		"pop %%ebx\n"
+#endif				  
+		: "=a" (max_cpuid), 
+		  "=d" (manufacturer[1]), "=c" (manufacturer[2]));
+  
+  /* Only Intel for now is done. */
+  if (grub_memcmp (manufacturer+1, "ineIntel", 12) != 0)
+    return sane_value;
+  
+#else
   asm volatile ("movl $0, %%eax\n"
 		"cpuid"
 		: "=a" (max_cpuid), "=b" (manufacturer[0]), 
@@ -133,15 +155,33 @@ guessfsb (void)
   /* Only Intel for now is done. */
   if (grub_memcmp (manufacturer, "GenuineIntel", 12) != 0)
     return sane_value;
+#endif
 
   /* Check Speedstep. */
   if (max_cpuid < 1)
     return sane_value;
 
+#ifdef APPLE_CC
+  asm volatile ("movl $1, %%eax\n"
+#ifdef __x86_64__
+		"push %%rbx\n"
+#else
+		"push %%ebx\n"
+#endif				  
+		"cpuid\n"
+#ifdef __x86_64__
+		"pop %%rbx\n"
+#else
+		"pop %%ebx\n"
+#endif
+		: "=c" (capabilities):
+		: "%rax", "%rdx");	
+#else
   asm volatile ("movl $1, %%eax\n"
 		"cpuid"
 		: "=c" (capabilities):
-		: "%eax", "%ebx", "%edx");
+		: "%rax", "%rbx", "%rdx");
+#endif
 
   if (! (capabilities & (1 << 7)))
     return sane_value;