| This directory contains machine independent implementations of floating point |
| operations. The implementations are nested in the namespace |
| `LIBC_NAMESPACE::fputil::generic`. This is to facilitate calling these generic |
| implementations from machine dependent implementations. Consider the example of |
| the fuse-multiply-add operation (FMA). The C standard library requires three |
| different flavors, `fma` which operates double precision numbers, `fmaf` which |
| operates on single precision numbers, and `fmal` which operates on `long double` |
| numbers. On aarch64, there are hardware instructions which implement the single |
| and double precision flavors but not the `long double` flavor. For such targets, |
| we want to be able to call the generic `long double` implementation from the |
| `long double` flavor. By putting the generic implementations in a separate |
| nested namespace, we will be to call them as follows: |
| |
| ``` |
| namespace LIBC_NAMESPACE { |
| namespace fputil { |
| |
| long double fmal(long double x, long double y, long double z) { |
| return generic::fmal(x, y, z); |
| } |
| |
| } // namespace fputil |
| } // namespace LIBC_NAMESPACE |
| ``` |
| |
| Note that actual code might not be as straightforward as above (for example, |
| we might want to prevent implicit type promotions by using some template |
| facilities). But, the general idea is very similar. |
