Various cleanup in bigint implementation:

Various cleanup in bigint implementation:
- reduce number of digit array allocations in divRem.
- shortcut reduce step in Classic reduction when possible.
- do not throw out of memory when value shifted left is zero.
- refactor code for future shifting operation intrinsics.
- and more...

R=srdjan@google.com

Committed: https://code.google.com/p/dart/source/detail?r=44750

[regis, 2015-03-26 23:47:37]

regis@google.com changed reviewers:
+ srdjan@google.com

[srdjan, 2015-03-27 18:15:51]

lgtm

https://codereview.chromium.org/1038253002/diff/1/runtime/lib/bigint.dart
File runtime/lib/bigint.dart (right):

https://codereview.chromium.org/1038253002/diff/1/runtime/lib/bigint.dart#new...
runtime/lib/bigint.dart:274: var d = digits[i];
final d

https://codereview.chromium.org/1038253002/diff/1/runtime/lib/bigint.dart#new...
runtime/lib/bigint.dart:298: var d = x_digits[i];
ditto

https://codereview.chromium.org/1038253002/diff/1/runtime/lib/bigint.dart#new...
runtime/lib/bigint.dart:333: var d = digits[i];
ditto

https://codereview.chromium.org/1038253002/diff/1/runtime/lib/bigint.dart#new...
runtime/lib/bigint.dart:370: var d = x_digits[i];
ditto

[regis, 2015-03-27 18:21:10]

Thanks!

https://codereview.chromium.org/1038253002/diff/1/runtime/lib/bigint.dart
File runtime/lib/bigint.dart (right):

https://codereview.chromium.org/1038253002/diff/1/runtime/lib/bigint.dart#new...
runtime/lib/bigint.dart:274: var d = digits[i];
On 2015/03/27 18:15:51, srdjan wrote:
> final d

Done.

https://codereview.chromium.org/1038253002/diff/1/runtime/lib/bigint.dart#new...
runtime/lib/bigint.dart:298: var d = x_digits[i];
On 2015/03/27 18:15:51, srdjan wrote:
> ditto

Done.

https://codereview.chromium.org/1038253002/diff/1/runtime/lib/bigint.dart#new...
runtime/lib/bigint.dart:333: var d = digits[i];
On 2015/03/27 18:15:51, srdjan wrote:
> ditto

Done.

https://codereview.chromium.org/1038253002/diff/1/runtime/lib/bigint.dart#new...
runtime/lib/bigint.dart:370: var d = x_digits[i];
On 2015/03/27 18:15:51, srdjan wrote:
> ditto

Done.

[regis, 2015-03-27 18:21:22]

Committed patchset #2 (id:20001) manually as r44750 (presubmit successful).