Remove recursive call from 32 bit operator-

[mborland]

Closes: #692

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 99.2%. Comparing base (73669da) to head (14067a4).

Additional details and impacted files

[](https://app.codecov.io/gh/cppalliance/decimal/pull/693?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=cppalliance) ```diff @@ Coverage Diff @@ ## develop #693 +/- ## ========================================= + Coverage 99.1% 99.2% +0.1% ========================================= Files 230 230 Lines 16347 16334 -13 Branches 1757 1753 -4 ========================================= - Hits 16199 16188 -11 + Misses 148 146 -2 ``` | [Files](https://app.codecov.io/gh/cppalliance/decimal/pull/693?dropdown=coverage&src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=cppalliance) | Coverage Δ | | |---|---|---| | [include/boost/decimal/decimal32.hpp](https://app.codecov.io/gh/cppalliance/decimal/pull/693?src=pr&el=tree&filepath=include%2Fboost%2Fdecimal%2Fdecimal32.hpp&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=cppalliance#diff-aW5jbHVkZS9ib29zdC9kZWNpbWFsL2RlY2ltYWwzMi5ocHA=) | `99.8% <100.0%> (-<0.1%)` | :arrow_down: | | [include/boost/decimal/decimal32\_fast.hpp](https://app.codecov.io/gh/cppalliance/decimal/pull/693?src=pr&el=tree&filepath=include%2Fboost%2Fdecimal%2Fdecimal32_fast.hpp&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=cppalliance#diff-aW5jbHVkZS9ib29zdC9kZWNpbWFsL2RlY2ltYWwzMl9mYXN0LmhwcA==) | `97.1% <100.0%> (-<0.1%)` | :arrow_down: | | [include/boost/decimal/detail/sub\_impl.hpp](https://app.codecov.io/gh/cppalliance/decimal/pull/693?src=pr&el=tree&filepath=include%2Fboost%2Fdecimal%2Fdetail%2Fsub_impl.hpp&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=cppalliance#diff-aW5jbHVkZS9ib29zdC9kZWNpbWFsL2RldGFpbC9zdWJfaW1wbC5ocHA=) | `98.7% <100.0%> (+1.3%)` | :arrow_up: | ... and [2 files with indirect coverage changes](https://app.codecov.io/gh/cppalliance/decimal/pull/693/indirect-changes?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=cppalliance) ------ [Continue to review full report in Codecov by Sentry](https://app.codecov.io/gh/cppalliance/decimal/pull/693?dropdown=coverage&src=pr&el=continue&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=cppalliance). > **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=cppalliance) > `Δ = absolute (impact)`, `ø = not affected`, `? = missing data` > Powered by [Codecov](https://app.codecov.io/gh/cppalliance/decimal/pull/693?dropdown=coverage&src=pr&el=footer&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=cppalliance). Last update [73669da...14067a4](https://app.codecov.io/gh/cppalliance/decimal/pull/693?dropdown=coverage&src=pr&el=lastupdated&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=cppalliance). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=cppalliance).