Import of Linus's Linux 1.1.68

1 files changed, 38 insertions, 0 deletions

diff --git a/include/asm-alpha/delay.h b/include/asm-alpha/delay.h
new file mode 100644
index 000000000..87e69f657
--- /dev/null
+++ b/include/asm-alpha/delay.h
@@ -0,0 +1,38 @@
+#ifndef __ALPHA_DELAY_H
+#define __ALPHA_DELAY_H
+
+extern unsigned long loops_per_sec;
+
+/*
+ * Copyright (C) 1993 Linus Torvalds
+ *
+ * Delay routines, using a pre-computed "loops_per_second" value.
+ */
+
+extern __inline__ void __delay(unsigned long loops)
+{
+	__asm__ __volatile__(".align 3\n"
+		"1:\tsubq %0,1,%0\n\t"
+		"bge %0,1b": "=r" (loops) : "0" (loops));
+}
+
+/*
+ * division by multiplication: you don't have to worry about
+ * loss of precision.
+ *
+ * Use only for very small delays ( < 1 msec).  Should probably use a
+ * lookup table, really, as the multiplications take much too long with
+ * short delays.  This is a "reasonable" implementation, though (and the
+ * first constant multiplications gets optimized away if the delay is
+ * a constant)
+ */
+extern __inline__ void udelay(unsigned long usecs)
+{
+	usecs *= 0x000010c6f7a0b5edUL;		/* 2**64 / 1000000 */
+	__asm__("umulh %1,%2,%0"
+		:"=r" (usecs)
+		:"r" (usecs),"r" (loops_per_sec));
+	__delay(usecs);
+}
+
+#endif /* defined(__ALPHA_DELAY_H) */