summaryrefslogtreecommitdiffstats
path: root/kernel/arch/powerpc/lib/div64.S
diff options
context:
space:
mode:
authorYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 12:17:53 -0700
committerYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 15:44:42 -0700
commit9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (patch)
tree1c9cafbcd35f783a87880a10f85d1a060db1a563 /kernel/arch/powerpc/lib/div64.S
parent98260f3884f4a202f9ca5eabed40b1354c489b29 (diff)
Add the rt linux 4.1.3-rt3 as base
Import the rt linux 4.1.3-rt3 as OPNFV kvm base. It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and the base is: commit 0917f823c59692d751951bf5ea699a2d1e2f26a2 Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Date: Sat Jul 25 12:13:34 2015 +0200 Prepare v4.1.3-rt3 Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> We lose all the git history this way and it's not good. We should apply another opnfv project repo in future. Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423 Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
Diffstat (limited to 'kernel/arch/powerpc/lib/div64.S')
-rw-r--r--kernel/arch/powerpc/lib/div64.S59
1 files changed, 59 insertions, 0 deletions
diff --git a/kernel/arch/powerpc/lib/div64.S b/kernel/arch/powerpc/lib/div64.S
new file mode 100644
index 000000000..83d9832fd
--- /dev/null
+++ b/kernel/arch/powerpc/lib/div64.S
@@ -0,0 +1,59 @@
+/*
+ * Divide a 64-bit unsigned number by a 32-bit unsigned number.
+ * This routine assumes that the top 32 bits of the dividend are
+ * non-zero to start with.
+ * On entry, r3 points to the dividend, which get overwritten with
+ * the 64-bit quotient, and r4 contains the divisor.
+ * On exit, r3 contains the remainder.
+ *
+ * Copyright (C) 2002 Paul Mackerras, IBM Corp.
+ *
+ * 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.
+ */
+#include <asm/ppc_asm.h>
+#include <asm/processor.h>
+
+_GLOBAL(__div64_32)
+ lwz r5,0(r3) # get the dividend into r5/r6
+ lwz r6,4(r3)
+ cmplw r5,r4
+ li r7,0
+ li r8,0
+ blt 1f
+ divwu r7,r5,r4 # if dividend.hi >= divisor,
+ mullw r0,r7,r4 # quotient.hi = dividend.hi / divisor
+ subf. r5,r0,r5 # dividend.hi %= divisor
+ beq 3f
+1: mr r11,r5 # here dividend.hi != 0
+ andis. r0,r5,0xc000
+ bne 2f
+ cntlzw r0,r5 # we are shifting the dividend right
+ li r10,-1 # to make it < 2^32, and shifting
+ srw r10,r10,r0 # the divisor right the same amount,
+ addc r9,r4,r10 # rounding up (so the estimate cannot
+ andc r11,r6,r10 # ever be too large, only too small)
+ andc r9,r9,r10
+ addze r9,r9
+ or r11,r5,r11
+ rotlw r9,r9,r0
+ rotlw r11,r11,r0
+ divwu r11,r11,r9 # then we divide the shifted quantities
+2: mullw r10,r11,r4 # to get an estimate of the quotient,
+ mulhwu r9,r11,r4 # multiply the estimate by the divisor,
+ subfc r6,r10,r6 # take the product from the divisor,
+ add r8,r8,r11 # and add the estimate to the accumulated
+ subfe. r5,r9,r5 # quotient
+ bne 1b
+3: cmplw r6,r4
+ blt 4f
+ divwu r0,r6,r4 # perform the remaining 32-bit division
+ mullw r10,r0,r4 # and get the remainder
+ add r8,r8,r0
+ subf r6,r10,r6
+4: stw r7,0(r3) # return the quotient in *r3
+ stw r8,4(r3)
+ mr r3,r6 # return the remainder in r3
+ blr