Merge #1958

1958: Remove core::intrinsics::math r=ppannuto a=bradjc

Part of #1654.

This math is old, and probably shouldn't be in the kernel. The only thing using it is a capsule for an obsolete chip. There was some discussion about this somewhere, and I think the conclusion was we don't really need a capsule for a sensor that is not on any boards and is an obsolete part.



### Testing Strategy

travis


### TODO or Help Wanted

n/a


### Documentation Updated

- [x] Updated the relevant files in `/docs`, or no updates are required.

### Formatting

- [x] Ran `make prepush`.


Co-authored-by: Brad Campbell <bradjc5@gmail.com>

capsules/README.md

@@ -36,7 +36,6 @@ These implement a driver to setup and read various physical sensors.
 - **[LPS25HB](src/lps25hb.rs)**: Pressure sensor.
 - **[MLX90614](src/mlx90614.rs)**: Infrared temperature sensor.
 - **[SI7021](src/si7021.rs)**: Temperature and humidity sensor.
-- **[TMP006](src/tmp006.rs)**: Infrared temperature sensor.
 - **[TSL2561](src/tsl2561.rs)**: Light sensor.
 
 These drivers provide support for various ICs.

capsules/src/lib.rs

@@ -61,7 +61,6 @@ pub mod si7021;
 pub mod spi;
 pub mod st7735;
 pub mod temperature;
-pub mod tmp006;
 pub mod tsl2561;
 pub mod usb;
 pub mod virtual_alarm;

kernel/src/common/math.rs

@@ -1,33 +1,6 @@
 //! Helper functions for common mathematical operations.
 
 use core::convert::{From, Into};
-use core::intrinsics as int;
-
-// wrappers for unsafe core::intrinsics math functions
-//  core::intrinsics functions can be found at
-//      https://doc.rust-lang.org/core/intrinsics/
-//  add additional wrappers as needed
-
-/// Provide `sqrtf32` with the unsafe hidden.
-pub fn sqrtf32(num: f32) -> f32 {
-    unsafe { int::sqrtf32(num) }
-}
-
-// errno from stdlib for use in Rust
-
-extern "C" {
-    fn __errno() -> &'static mut i32;
-}
-
-/// Return errno value and zero it out.
-pub fn get_errno() -> i32 {
-    unsafe {
-        let errnoaddr = __errno();
-        let ret = *errnoaddr;
-        *errnoaddr = 0;
-        ret
-    }
-}
 
 /// Get closest power of two greater than the given number.
 pub fn closest_power_of_two(mut num: u32) -> u32 {