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| author | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2006-09-28 16:55:39 +0200 |
|---|---|---|
| committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2006-09-28 16:55:39 +0200 |
| commit | d9f7a745d55527d0d41684b22506a86c4381f7f1 (patch) | |
| tree | ea8870ef06c3723ad59b78aac97bfe8152894c72 /include/asm-s390/div64.h | |
| parent | 1fce518e8e7de62597c823d6d795cafc694e7910 (diff) | |
| download | linux-d9f7a745d55527d0d41684b22506a86c4381f7f1.tar.bz2 | |
[S390] __div64_32 for 31 bit.
The clocksource infrastructure introduced with commit
ad596171ed635c51a9eef829187af100cbf8dcf7 broke 31 bit s390.
The reason is that the do_div() primitive for 31 bit always
had a restriction: it could only divide an unsigned 64 bit
integer by an unsigned 31 bit integer. The clocksource code
now uses do_div() with a base value that has the most
significant bit set. The result is that clock->cycle_interval
has a funny value which causes the linux time to jump around
like mad.
The solution is "obvious": implement a proper __div64_32
function for 31 bit s390.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'include/asm-s390/div64.h')
| -rw-r--r-- | include/asm-s390/div64.h | 48 |
1 files changed, 0 insertions, 48 deletions
diff --git a/include/asm-s390/div64.h b/include/asm-s390/div64.h index af098dc3cf59..6cd978cefb28 100644 --- a/include/asm-s390/div64.h +++ b/include/asm-s390/div64.h @@ -1,49 +1 @@ -#ifndef __S390_DIV64 -#define __S390_DIV64 - -#ifndef __s390x__ - -/* for do_div "base" needs to be smaller than 2^31-1 */ -#define do_div(n, base) ({ \ - unsigned long long __n = (n); \ - unsigned long __r; \ - \ - asm (" slr 0,0\n" \ - " l 1,%1\n" \ - " srdl 0,1\n" \ - " dr 0,%2\n" \ - " alr 1,1\n" \ - " alr 0,0\n" \ - " lhi 2,1\n" \ - " n 2,%1\n" \ - " alr 0,2\n" \ - " clr 0,%2\n" \ - " jl 0f\n" \ - " slr 0,%2\n" \ - " ahi 1,1\n" \ - "0: st 1,%1\n" \ - " l 1,4+%1\n" \ - " srdl 0,1\n" \ - " dr 0,%2\n" \ - " alr 1,1\n" \ - " alr 0,0\n" \ - " lhi 2,1\n" \ - " n 2,4+%1\n" \ - " alr 0,2\n" \ - " clr 0,%2\n" \ - " jl 1f\n" \ - " slr 0,%2\n" \ - " ahi 1,1\n" \ - "1: st 1,4+%1\n" \ - " lr %0,0" \ - : "=d" (__r), "=m" (__n) \ - : "d" (base), "m" (__n) : "0", "1", "2", "cc" ); \ - (n) = (__n); \ - __r; \ -}) - -#else /* __s390x__ */ #include <asm-generic/div64.h> -#endif /* __s390x__ */ - -#endif |