Index: uspace/lib/libc/arch/ia32/src/entry.s
===================================================================
--- uspace/lib/libc/arch/ia32/src/entry.s	(revision c98e6ee244a8e271a395a052069c23bca4f8b538)
+++ uspace/lib/libc/arch/ia32/src/entry.s	(revision 025759cdc4055ca51d57f936b27dc11c8f46f1b3)
@@ -27,4 +27,7 @@
 #
 
+INTEL_CPUID_STANDARD = 1
+INTEL_SEP = 11
+
 .section .init, "ax"
 
@@ -35,5 +38,5 @@
 ## User-space task entry point
 #
-# %ebx contains the PCB pointer
+# %edi contains the PCB pointer
 #
 __entry:
@@ -44,6 +47,15 @@
 	# Do not set %gs, it contains descriptor that can see TLS
 
+	# Detect the mechanism used for making syscalls
+	movl $(INTEL_CPUID_STANDARD), %eax
+	cpuid
+	bt $(INTEL_SEP), %edx
+	jnc 0f
+	leal __syscall_fast_func, %eax
+	movl $__syscall_fast, (%eax)
+0:
+
 	# Pass the PCB pointer to __main as the first argument
-	pushl %ebx
+	pushl %edi
 	call __main