Initial revision

lib_ppc/ticks.S

+/*
+ * (C) Copyright 2000, 2001
+ * Erik Theisen, Wave 7 Optics, etheisen@mindspring.com.
+ *  base on code by
+ * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#include <ppc_asm.tmpl>
+#include <ppc_defs.h>
+#include <config.h>
+#include <watchdog.h>
+
+/*
+ * unsigned long long get_ticks(void);
+ *
+ * read timebase as "long long"
+ */
+	.globl	get_ticks
+get_ticks:
+1:	mftbu	r3
+	mftb	r4
+	mftbu	r5
+	cmp	0,r3,r5
+	bne	1b
+	blr
+
+/*
+ * Delay for a number of ticks
+ */
+	.globl	wait_ticks
+wait_ticks:
+	mflr	r8		/* save link register */
+	mr	r7, r3		/* save tick count */
+	bl	get_ticks	/* Get start time */
+
+	/* Calculate end time */
+	addc    r7, r4, r7	/* Compute end time lower */
+	addze	r6, r3		/*     and end time upper */
+
+	WATCHDOG_RESET		/* Trigger watchdog, if needed */
+1:	bl	get_ticks	/* Get current time */
+	subfc	r4, r4, r7	/* Subtract current time from end time */
+	subfe.	r3, r3, r6
+	bge	1b		/* Loop until time expired */
+
+	mtlr	r8		/* restore link register */
+	blr