[linuxsh-dev] 2.5.69 linux/time.h

[kaz K. <kk...@rr...>]

Hi,

Sugioka-san pointed me that the most recent change of linux/time.h
in 2.5.69 produces 64-bit/64-bit unsigned integer divisions and calls
__udivdi3 in libgcc.a. It causes a bug with using FPU badly in SH-4
kernel. So I've checked an attached patch in on HEAD as a temporary
workaround for it.
These divisions come from the computation with TICK_NSEC(TICK_USEC)
which is non-constant for SH only and it looks to me that only
64-bit/32-bit divisions are required.
We have to write true 64-bit/64-bit one if it's not the case.

Regards,
	kaz
--
2003-05-07  Kaz Kojima  <kk...@rr...>

	* arch/sh/lib/udivdi3.c: New file.
	* arch/sh/lib/Makefile (obj-y): Add udivdi3.o.

diff -u3prN linux-2.5.69-orig/arch/sh/lib/Makefile LOCAL/linux-2.5.69-sf/arch/sh/lib/Makefile
--- linux-2.5.69-orig/arch/sh/lib/Makefile	Wed Mar  5 12:29:18 2003
+++ LOCAL/linux-2.5.69-sf/arch/sh/lib/Makefile	Tue May  6 20:15:31 2003
@@ -4,4 +4,4 @@
 
 L_TARGET = lib.a
 obj-y  = delay.o memcpy.o memset.o memmove.o memchr.o \
-	 checksum.o strcasecmp.o strlen.o div64.o
+	 checksum.o strcasecmp.o strlen.o div64.o udivdi3.o
diff -u3prN linux-2.5.69-orig/arch/sh/lib/udivdi3.c LOCAL/linux-2.5.69-sf/arch/sh/lib/udivdi3.c
--- linux-2.5.69-orig/arch/sh/lib/udivdi3.c	Thu Jan  1 09:00:00 1970
+++ LOCAL/linux-2.5.69-sf/arch/sh/lib/udivdi3.c	Tue May  6 20:14:57 2003
@@ -0,0 +1,16 @@
+/*
+ * Simple __udivdi3 function which doesn't use FPU.
+ */
+
+#include <linux/types.h>
+
+extern u64 __div64_32(u64 n, u32 d);
+extern void panic(const char * fmt, ...);
+
+u64 __udivdi3(u64 n, u64 d)
+{
+	if (d & ~0xffffffff)
+		panic("Need true 64-bit/64-bit division");
+	return __div64_32(n, (u32)d);
+}
+