diff options
| author | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2006-09-28 10:55:39 -0400 |
|---|---|---|
| committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2006-09-28 10:55:39 -0400 |
| commit | d9f7a745d55527d0d41684b22506a86c4381f7f1 (patch) | |
| tree | ea8870ef06c3723ad59b78aac97bfe8152894c72 /include/asm-s390 | |
| parent | 1fce518e8e7de62597c823d6d795cafc694e7910 (diff) | |
[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')
| -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 @@ | |||
| 1 | #ifndef __S390_DIV64 | ||
| 2 | #define __S390_DIV64 | ||
| 3 | |||
| 4 | #ifndef __s390x__ | ||
| 5 | |||
| 6 | /* for do_div "base" needs to be smaller than 2^31-1 */ | ||
| 7 | #define do_div(n, base) ({ \ | ||
| 8 | unsigned long long __n = (n); \ | ||
| 9 | unsigned long __r; \ | ||
| 10 | \ | ||
| 11 | asm (" slr 0,0\n" \ | ||
| 12 | " l 1,%1\n" \ | ||
| 13 | " srdl 0,1\n" \ | ||
| 14 | " dr 0,%2\n" \ | ||
| 15 | " alr 1,1\n" \ | ||
| 16 | " alr 0,0\n" \ | ||
| 17 | " lhi 2,1\n" \ | ||
| 18 | " n 2,%1\n" \ | ||
| 19 | " alr 0,2\n" \ | ||
| 20 | " clr 0,%2\n" \ | ||
| 21 | " jl 0f\n" \ | ||
| 22 | " slr 0,%2\n" \ | ||
| 23 | " ahi 1,1\n" \ | ||
| 24 | "0: st 1,%1\n" \ | ||
| 25 | " l 1,4+%1\n" \ | ||
| 26 | " srdl 0,1\n" \ | ||
| 27 | " dr 0,%2\n" \ | ||
| 28 | " alr 1,1\n" \ | ||
| 29 | " alr 0,0\n" \ | ||
| 30 | " lhi 2,1\n" \ | ||
| 31 | " n 2,4+%1\n" \ | ||
| 32 | " alr 0,2\n" \ | ||
| 33 | " clr 0,%2\n" \ | ||
| 34 | " jl 1f\n" \ | ||
| 35 | " slr 0,%2\n" \ | ||
| 36 | " ahi 1,1\n" \ | ||
| 37 | "1: st 1,4+%1\n" \ | ||
| 38 | " lr %0,0" \ | ||
| 39 | : "=d" (__r), "=m" (__n) \ | ||
| 40 | : "d" (base), "m" (__n) : "0", "1", "2", "cc" ); \ | ||
| 41 | (n) = (__n); \ | ||
| 42 | __r; \ | ||
| 43 | }) | ||
| 44 | |||
| 45 | #else /* __s390x__ */ | ||
| 46 | #include <asm-generic/div64.h> | #include <asm-generic/div64.h> | |
| 47 | #endif /* __s390x__ */ | ||
| 48 | |||
| 49 | #endif | ||