Clarify which floats have implementation of which accuracy.

Clarify which paper we tralk about.

README.md

@@ -18,12 +18,13 @@ either a square root (and possibly a division) or a logarithm and then a series
 of multiplications and additions by fixed constants and finished with a division.
 
 The crate provides two approximations of each branch, one with 50 bits of
-accuracy and one with 24 bits. The one with 50 bits of accuracy uses higher
+accuracy (implemented on 64-bit floats) and one with 24 bits
+(implemented on 32- and 64-bit floats). The one with 50 bits of accuracy uses higher
 degree polynomials in the rational functions compared to the one with only 24 bits,
 and thus more of the multiplications and additions by constants.
 
-This crate can also evaluate the approximation with 24 bits of accuracy on
-32-bit floats, even though it is defined on 64-bit floats in the paper.
+This crate can evaluate the approximation with 24 bits of accuracy on
+32-bit floats, even though it is defined on 64-bit floats in Fukushima's paper.
 This may result in a reduction in the accuracy to less than 24 bits,
 but this reduction has not been quantified by the author of this crate.
 

src/lib.rs

@@ -6,12 +6,13 @@
 //! It is implemented in code as conditional switches on the input value followed by either a square root (and possibly a division) or a logarithm
 //! and then a series of multiplications and additions by fixed constants and finished with a division.
 //!
-//! The crate provides two approximations of each branch, one with 50 bits of accuracy and one with 24 bits.
-//! The one with 50 bits of accuracy uses higher degree polynomials in the rational functions compared to the one with only 24 bits,
+//! The crate provides two approximations of each branch, one with 50 bits of accuracy (implemented on 64-bit floats) and one with 24 bits
+//! (implemented on 32- and 64-bit floats). The one with 50 bits of accuracy uses higher degree polynomials
+//! in the rational functions compared to the one with only 24 bits,
 //! and thus more of the multiplications and additions by constants.
 //!
-//! This crate can also evaluate the approximation with 24 bits of accuracy on
-//! 32-bit floats, even though it is defined on 64-bit floats in the paper.
+//! This crate can evaluate the approximation with 24 bits of accuracy on
+//! 32-bit floats, even though it is defined on 64-bit floats in Fukushima's paper.
 //! This may result in a reduction in the accuracy to less than 24 bits,
 //! but this reduction has not been quantified by the author of this crate.
 //!