Merge pull request #4238 from dhalbert/cdc-avoid-extra-float-libs

usb_cdc: avoid pulling in extra float-uint64 routines

1 files changed, 9 insertions, 0 deletions

diff --git a/py/objfloat.c b/py/objfloat.c
index 80f10e816..329a8b90e 100644
--- a/py/objfloat.c
+++ b/py/objfloat.c
@@ -340,6 +340,15 @@ mp_float_t uint64_to_float(uint64_t ui64) {
     return (mp_float_t) ((uint32_t) (ui64 >> 32) * 4294967296.0f + (uint32_t) (ui64 & 0xffffffff));
 }
 
+// Convert a uint64_t to a 32-bit float to a uint64_t without invoking extra math routines.
+// which are large.
+// Assume f >= 0.
+uint64_t float_to_uint64(float f) {
+    // 4294967296 = 2^32
+    const uint32_t upper_half = (uint32_t) (f /  4294967296.0f);
+    const uint32_t lower_half = (uint32_t) f;
+    return (((uint64_t) upper_half) << 32) + lower_half;
+}
 #pragma GCC diagnostic pop
 
 #endif // MICROPY_PY_BUILTINS_FLOAT