diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1e512038..c73313e0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,11 @@
ArduinoJson: change log
=======================
+HEAD
+----
+
+* Improved float serialization when `-fsingle-precision-constant` is used
+
v5.13.2
-------
diff --git a/src/ArduinoJson/TypeTraits/FloatTraits.hpp b/src/ArduinoJson/TypeTraits/FloatTraits.hpp
index 5044807a..648cc82f 100644
--- a/src/ArduinoJson/TypeTraits/FloatTraits.hpp
+++ b/src/ArduinoJson/TypeTraits/FloatTraits.hpp
@@ -44,28 +44,46 @@ struct FloatTraits {
static T positiveBinaryPowerOfTen(int index) {
static T factors[] = {
- 1e1, 1e2, 1e4, 1e8, 1e16, 1e32,
- // workaround to support platforms with single precision literals
- forge(0x4D384F03, 0xE93FF9F5), forge(0x5A827748, 0xF9301D32),
- forge(0x75154FDD, 0x7F73BF3C)};
+ 1e1,
+ 1e2,
+ 1e4,
+ 1e8,
+ 1e16,
+ forge(0x4693B8B5, 0xB5056E17), // 1e32
+ forge(0x4D384F03, 0xE93FF9F5), // 1e64
+ forge(0x5A827748, 0xF9301D32), // 1e128
+ forge(0x75154FDD, 0x7F73BF3C) // 1e256
+ };
return factors[index];
}
static T negativeBinaryPowerOfTen(int index) {
static T factors[] = {
- 1e-1, 1e-2, 1e-4, 1e-8, 1e-16, 1e-32,
- // workaround to support platforms with single precision literals
- forge(0x32A50FFD, 0x44F4A73D), forge(0x255BBA08, 0xCF8C979D),
- forge(0x0AC80628, 0x64AC6F43)};
+ forge(0x3FB99999, 0x9999999A), // 1e-1
+ forge(0x3F847AE1, 0x47AE147B), // 1e-2
+ forge(0x3F1A36E2, 0xEB1C432D), // 1e-4
+ forge(0x3E45798E, 0xE2308C3A), // 1e-8
+ forge(0x3C9CD2B2, 0x97D889BC), // 1e-16
+ forge(0x3949F623, 0xD5A8A733), // 1e-32
+ forge(0x32A50FFD, 0x44F4A73D), // 1e-64
+ forge(0x255BBA08, 0xCF8C979D), // 1e-128
+ forge(0x0AC80628, 0x64AC6F43) // 1e-256
+ };
return factors[index];
}
static T negativeBinaryPowerOfTenPlusOne(int index) {
static T factors[] = {
- 1e0, 1e-1, 1e-3, 1e-7, 1e-15, 1e-31,
- // workaround to support platforms with single precision literals
- forge(0x32DA53FC, 0x9631D10D), forge(0x25915445, 0x81B7DEC2),
- forge(0x0AFE07B2, 0x7DD78B14)};
+ 1e0,
+ forge(0x3FB99999, 0x9999999A), // 1e-1
+ forge(0x3F50624D, 0xD2F1A9FC), // 1e-3
+ forge(0x3E7AD7F2, 0x9ABCAF48), // 1e-7
+ forge(0x3CD203AF, 0x9EE75616), // 1e-15
+ forge(0x398039D6, 0x65896880), // 1e-31
+ forge(0x32DA53FC, 0x9631D10D), // 1e-63
+ forge(0x25915445, 0x81B7DEC2), // 1e-127
+ forge(0x0AFE07B2, 0x7DD78B14) // 1e-255
+ };
return factors[index];
}
@@ -77,6 +95,9 @@ struct FloatTraits {
return forge(0x7ff00000, 0x00000000);
}
+ // constructs a double floating point values from its binary representation
+ // we use this function to workaround platforms with single precision literals
+ // (for example, when -fsingle-precision-constant is passed to GCC)
static T forge(uint32_t msb, uint32_t lsb) {
union {
uint64_t integerBits;