diff --git a/sys/amd64/amd64/cpu_switch.S b/sys/amd64/amd64/cpu_switch.S
index 240c9558100..12542d74853 100644
--- a/sys/amd64/amd64/cpu_switch.S
+++ b/sys/amd64/amd64/cpu_switch.S
@@ -394,7 +394,7 @@ ENTRY(savectx)
 END(savectx)
 
 /*
- * resumectx(pcb in %rdi, cr3 in %rsi)
+ * resumectx(pcb, cr3)
  * Resuming processor state from pcb.
  */     
 ENTRY(resumectx)
diff --git a/sys/amd64/include/pcb.h b/sys/amd64/include/pcb.h
index 619fba5a8a3..35665f12e35 100644
--- a/sys/amd64/include/pcb.h
+++ b/sys/amd64/include/pcb.h
@@ -100,7 +100,7 @@ struct pcb {
 	register_t	pcb_xsmask;
 
 	/* fpu context for suspend/resume */
-	void *		pcb_fpususpend;
+	void		*pcb_fpususpend;
 
 	struct savefpu	*pcb_save;
 
@@ -142,7 +142,7 @@ clear_pcb_flags(struct pcb *pcb, const u_int flags)
 
 void	makectx(struct trapframe *, struct pcb *);
 int	savectx(struct pcb *) __returns_twice;
-void	resumectx(struct pcb *);
+void	resumectx(struct pcb *, register_t);
 
 #endif
 
diff --git a/sys/i386/acpica/acpi_wakecode.S b/sys/i386/acpica/acpi_wakecode.S
index 5f66ef13dcd..88f32d7c119 100644
--- a/sys/i386/acpica/acpi_wakecode.S
+++ b/sys/i386/acpica/acpi_wakecode.S
@@ -142,8 +142,8 @@ wakeup_32:
 	mov	%ax, %ds
 
 	/* Get PCB and return address. */
-	movl	wakeup_pcb - wakeup_start(%ebx), %esi
-	movl	wakeup_ret - wakeup_start(%ebx), %edi
+	movl	wakeup_pcb - wakeup_start(%ebx), %ecx
+	movl	wakeup_ret - wakeup_start(%ebx), %edx
 
 	/* Restore CR4 and CR3. */
 	movl	wakeup_cr4 - wakeup_start(%ebx), %eax
@@ -166,7 +166,7 @@ wakeup_32:
 	jmp	1f
 1:
 	/* Jump to return address. */
-	jmp	*%edi
+	jmp	*%edx
 
 	.data
 
diff --git a/sys/i386/i386/swtch.s b/sys/i386/i386/swtch.s
index adf554a4f7f..80aa6c418e6 100644
--- a/sys/i386/i386/swtch.s
+++ b/sys/i386/i386/swtch.s
@@ -460,13 +460,10 @@ ENTRY(savectx)
 END(savectx)
 
 /*
- * resumectx(pcb in %esi)
+ * resumectx(pcb) __fastcall
  * Resuming processor state from pcb.
  */
 ENTRY(resumectx)
-	/* Fetch PCB. */
-	movl	%esi,%ecx
-
 	/* Restore GDT. */
 	lgdt	PCB_GDT(%ecx)
 
diff --git a/sys/i386/include/pcb.h b/sys/i386/include/pcb.h
index 108ecfefd44..9cefed17688 100644
--- a/sys/i386/include/pcb.h
+++ b/sys/i386/include/pcb.h
@@ -97,7 +97,7 @@ struct trapframe;
 
 void	makectx(struct trapframe *, struct pcb *);
 int	savectx(struct pcb *) __returns_twice;
-void	resumectx(struct pcb *);
+void	resumectx(struct pcb *) __fastcall;
 #endif
 
 #endif /* _I386_PCB_H_ */