patch-2.4.6 linux/arch/alpha/lib/udelay.c

• Lines: 48
• Date: Wed Jun 20 11:10:27 2001
• Orig file: v2.4.5/linux/arch/alpha/lib/udelay.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.4.5/linux/arch/alpha/lib/udelay.c linux/arch/alpha/lib/udelay.c
@@ -0,0 +1,47 @@
+#include <linux/config.h>
+#include <linux/sched.h> /* for udelay's use of smp_processor_id */
+#include <asm/param.h>
+#include <asm/smp.h>
+#include <linux/delay.h>
+
+/*
+ * Copyright (C) 1993, 2000 Linus Torvalds
+ *
+ * Delay routines, using a pre-computed "loops_per_jiffy" value.
+ */
+
+/*
+ * Use only for very small delays (< 1 msec). 
+ *
+ * The active part of our cycle counter is only 32-bits wide, and
+ * we're treating the difference between two marks as signed.  On
+ * a 1GHz box, that's about 2 seconds.
+ */
+
+void __delay(int loops)
+{
+	int tmp;
+	__asm__ __volatile__(
+		"	rpcc %0\n"
+		"	addl %1,%0,%1\n"
+		"1:	rpcc %0\n"
+		"	subl %1,%0,%0\n"
+		"	bgt %0,1b"
+		: "=&r" (tmp), "=r" (loops) : "1"(loops));
+}
+
+void __udelay(unsigned long usecs, unsigned long lpj)
+{
+	usecs *= (((unsigned long)HZ << 32) / 1000000) * lpj;
+	__delay((long)usecs >> 32);
+}
+
+void udelay(unsigned long usecs)
+{
+#ifdef CONFIG_SMP
+	__udelay(usecs, cpu_data[smp_processor_id()].loops_per_jiffy);
+#else
+	__udelay(usecs, loops_per_jiffy);
+#endif
+}
+