Before I apply and test - will it work at all on I386 (see my prev. mail). I don't have such a platform to check video on.
bye, Ilan Justin Schoeman wrote: > Ilan Finci wrote: > >> Thanks, >> I've looked at the code of do_div on PPC, and it uses % and /. Will it >> still work? >> >> Also, I tried to use do_div on i386 (kernel 2.4.18), and I get wrong >> answer. Attached is a small test program, where do_div is the version >> from the i386 sources, and do_div1 is the version from PPC sources. >> >> The first one give wrong answer, while the second one works fine. What >> am I missing? Will the code in v4l2 that uses do_div works on Intel >> platforms? >> >> Thanks, >> Ilan >> >> Gerd Knorr wrote: >> >>>> /lib/modules/2.4.16/kernel/drivers/media/video/videodevX.o: >>>> unresolved symbol __udivdi3 >>>> /lib/modules/2.4.16/kernel/drivers/media/video/videodevX.o: >>>> unresolved symbol __umoddi3 >>> >>> >>> >>> >>> libgcc functions for 64bit math, which are not present in the kernel >>> because it isn't linked against libgcc. >>> >>> >>>> I see in videodevX.c that the function v4l2_math_div6432(...) I see >>>> that for intel cpus, there is an assembly code, and for others, a >>>> use of the '/' and '%', can this be the problem? >>> >>> >>> >>> >>> Yes. >>> >>> The modules in http://bytesex.org/patches/12_v4l2-2.4.19-pre2.diff.gz >>> have this fixed, they use the kernel functions for 64bit division. >>> >>> Gerd >> > > > Attached is a completely untested patch (well, it does build...) for > videodevX, that adds Gerd's math routines. Please give it a try, and > let me know if it works. > > -justin > > > ------------------------------------------------------------------------ > > diff -urN videodevX/videodev.h videodevX-newdiv/videodev.h > --- videodevX/videodev.h Thu Jun 14 07:45:23 2001 > +++ videodevX-newdiv/videodev.h Thu Mar 14 10:58:56 2002 > @@ -879,9 +879,6 @@ > extern void *v4l2_q_yank_node(struct v4l2_queue *q, struct v4l2_q_node *node); > extern int v4l2_q_last(struct v4l2_queue *q); > > -/* Math functions */ > -extern u32 v4l2_math_div6432(u64 a, u32 d, u32 *r); > - > /* Time functions */ > extern unsigned long v4l2_timestamp_divide(stamp_t t, > unsigned long p_100ns); > diff -urN videodevX/videodevX.c videodevX-newdiv/videodevX.c > --- videodevX/videodevX.c Thu Jun 14 07:45:23 2001 > +++ videodevX-newdiv/videodevX.c Thu Mar 14 11:03:42 2002 > @@ -42,19 +42,18 @@ > * 2.4 devfs support ported from 2.4 kernels by > * Dan Merillat <[EMAIL PROTECTED]> > * Added Gerd Knorrs v4l1 enhancements (Justin Schoeman) > + * Arch independant division hacked for Gerd Knor's v4l2 patch > */ > > #ifndef __KERNEL__ > #define __KERNEL__ > #endif > > - > #include <linux/config.h> > #ifndef EXPORT_SYMTAB > #define EXPORT_SYMTAB > #endif > > - > #include <linux/version.h> > #include <linux/module.h> > #include <linux/types.h> > @@ -66,13 +65,13 @@ > #include <linux/errno.h> > #include "videodev.h" > > - > #if LINUX_VERSION_CODE >= 0x020100 > #include <asm/uaccess.h> > #endif > #include <asm/system.h> > #include <asm/pgtable.h> > #include <asm/io.h> > +#include <asm/div64.h> > > #ifdef CONFIG_KMOD > #include <linux/kmod.h> > @@ -1132,7 +1131,7 @@ > int count, int *eof, void *data) > { > int len = 0; > - struct videodev_proc_data *d; > + struct videodev_proc_data *d = NULL; > struct list_head *tmp; > > list_for_each (tmp, &videodev_proc_list) { > @@ -1765,41 +1764,15 @@ > * Math functions > */ > > -u32 > -v4l2_math_div6432(u64 a, u32 d, u32 *r) > -{ > - u32 q, m; > -#ifdef __i386__ > -/* Danger: This function will fault if the quotient exceeds (1<<32) - 1 */ > - __asm__ __volatile__ ( > - " movl %2,%%eax\n" > - " movl %3,%%edx\n" > - " divl %4\n" > - " movl %%eax,%0\n" > - " movl %%edx,%1\n" > - : "=g" (q), "=g" (m) > - : "g" ((u32)a), "g" ((u32)(a >> 32)), "g" (d) > - : "eax", "edx" > - ); > -#else > - q = a / d; > - m = a % d; > -#endif > - if (r) *r = m; > - return q; > -} > - > unsigned long > v4l2_timestamp_divide(stamp_t t, unsigned long p_100ns) > { > - /* Note: 't' is in 1ns units, 'p_100ns' is in 100ns units, */ > - /* and the quotient is rounded */ > - u64 p; > - > - p = (u64)p_100ns * 100; /* 1ns units */ > - t >>= 6; /* /64 to allow p_100ns longer than 4 secs. */ > - p >>= 6; /* to keep quotient the same */ > - return v4l2_math_div6432((u64)t + (p >> 1), (u32)p, NULL); > + u32 p; > + > + p = ((u64)p_100ns * 100) >> 6; > + t = (t >> 6) + (p >> 1); > + do_div(t,p); > + return t; > } > > /* Force the timestamp to be an integer multiple of p_100ns */ > @@ -1877,13 +1850,16 @@ > unsigned long > v4l2_video_std_tpf(struct v4l2_standard *vs) > { > - return v4l2_math_div6432( > - (u64)vs->framerate.numerator * 10000000 > - + vs->framerate.denominator / 2, > - vs->framerate.denominator, > - NULL); > + u64 a; > + u32 b; > + > + a = (u64)vs->framerate.numerator * 10000000 + vs->framerate.denominator / 2; > + b = vs->framerate.denominator; > + do_div(a,b); > + return a; > } > > + > /* Used only in v4l2_video_std_confirm() */ > static void > catc1p2e6(__u8 *s, char c, int n) > @@ -2139,7 +2115,6 @@ > EXPORT_SYMBOL(v4l2_q_peek_tail); > EXPORT_SYMBOL(v4l2_q_yank_node); > EXPORT_SYMBOL(v4l2_q_last); > -EXPORT_SYMBOL(v4l2_math_div6432); > EXPORT_SYMBOL(v4l2_timestamp_divide); > EXPORT_SYMBOL(v4l2_timestamp_correct); > EXPORT_SYMBOL(v4l2_masterclock_register); -- Ilan Finci Engineering Manager Advanced Technology Development MobilEye Vision Technologies Ltd 24 Mishol Hadkalim st. Jerusalem, 97278, Israel Tel: 972-2-5866989 ext. 105 Fax: 972-2-5867720 E-Fax: 1-801-912-3251 Email: mailto:[EMAIL PROTECTED] http://www.mobileye.com
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