win: Fix ClockMonotonicNanoseconds()

win: Fix ClockMonotonicNanoseconds()

R=scottmg@chromium.org

Committed: https://chromium.googlesource.com/crashpad/crashpad/+/9a9076656fc499044a8ed2c570b7cd523afd380d

[Mark Mentovai, 2015-11-05 18:33:49]

mark@chromium.org changed reviewers:
+ scottmg@chromium.org

[scottmg, 2015-11-05 18:49:58]

lgtm

https://codereview.chromium.org/1419533014/diff/1/util/misc/clock_win.cc
File util/misc/clock_win.cc (right):

https://codereview.chromium.org/1419533014/diff/1/util/misc/clock_win.cc#newc...
util/misc/clock_win.cc:42: int64_t leftover_ticks = time.QuadPart % frequency;
frequency = 10, time.QuadPart = 98

whole_seconds = 98 / 10 = 9
leftover_ticks_old = 98 / 90 = 0
leftover_ticks_new = 98 % 10 = 8

result_nano = 9 * to_nano + 8 * to_nano / freq

Yup, no idea what I was doing. :/

[Mark Mentovai, 2015-11-05 18:58:10]

https://codereview.chromium.org/1419533014/diff/1/util/misc/clock_win.cc
File util/misc/clock_win.cc (right):

https://codereview.chromium.org/1419533014/diff/1/util/misc/clock_win.cc#newc...
util/misc/clock_win.cc:42: int64_t leftover_ticks = time.QuadPart % frequency;
scottmg wrote:
> frequency = 10, time.QuadPart = 98
> 
> whole_seconds = 98 / 10 = 9
> leftover_ticks_old = 98 / 90 = 0
> leftover_ticks_new = 98 % 10 = 8
> 
> result_nano = 9 * to_nano + 8 * to_nano / freq
> 
> Yup, no idea what I was doing. :/

I think you meant - instead of / on this line, but the % is just as good if not
better.

[Mark Mentovai, 2015-11-06 15:16:04]

Committed patchset #1 (id:1) manually as
9a9076656fc499044a8ed2c570b7cd523afd380d (presubmit successful).