summaryrefslogtreecommitdiffstats
path: root/include/asm-i386/delay.h
diff options
context:
space:
mode:
Diffstat (limited to 'include/asm-i386/delay.h')
-rw-r--r--include/asm-i386/delay.h35
1 files changed, 35 insertions, 0 deletions
diff --git a/include/asm-i386/delay.h b/include/asm-i386/delay.h
new file mode 100644
index 000000000..7ff5f769c
--- /dev/null
+++ b/include/asm-i386/delay.h
@@ -0,0 +1,35 @@
+#ifndef _I386_DELAY_H
+#define _I386_DELAY_H
+
+/*
+ * Copyright (C) 1993 Linus Torvalds
+ *
+ * Delay routines, using a pre-computed "loops_per_second" value.
+ */
+
+extern __inline__ void __delay(int loops)
+{
+ __asm__(".align 2,0x90\n1:\tdecl %0\n\tjns 1b": :"a" (loops):"ax");
+}
+
+/*
+ * 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 *= 0x000010c6; /* 2**32 / 1000000 */
+ __asm__("mull %0"
+ :"=d" (usecs)
+ :"a" (usecs),"0" (loops_per_sec)
+ :"ax");
+ __delay(usecs);
+}
+
+#endif /* defined(_I386_DELAY_H) */