diff --git a/src/cpu/intel/car/p4-netburst/cache_as_ram.S b/src/cpu/intel/car/p4-netburst/cache_as_ram.S
index 71ec9e3..9ac9e22 100644
--- a/src/cpu/intel/car/p4-netburst/cache_as_ram.S
+++ b/src/cpu/intel/car/p4-netburst/cache_as_ram.S
@@ -359,6 +359,16 @@
 	andl	$0xfffffff0, %esp
 	subl	$4, %esp
 
+#if ENV_X86_64
+	#include <cpu/x86/64bit/entry64.inc>
+
+	movd	%mm2, %rdi
+	shlq	$32, %rdi	/* BIST */
+	movd	%mm1, %rsi
+	or	%rsi, %rdi	/* tsc[63:32] */
+	movd	%mm0, %rsi	/* tsc[31:0] */
+
+#else
 	/* push TSC and BIST to stack */
 	movd	%mm0, %eax
 	pushl	%eax	/* BIST */
@@ -366,6 +376,7 @@
 	pushl	%eax	/* tsc[63:32] */
 	movd	%mm1, %eax
 	pushl	%eax	/* tsc[31:0] */
+#endif
 
 before_c_entry:
 	post_code(0x2f)