diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/corelib/global/qfloat16.h | 16 |
1 files changed, 14 insertions, 2 deletions
diff --git a/src/corelib/global/qfloat16.h b/src/corelib/global/qfloat16.h index ab480f84f5..acf9220490 100644 --- a/src/corelib/global/qfloat16.h +++ b/src/corelib/global/qfloat16.h @@ -172,8 +172,20 @@ inline qfloat16::qfloat16(float f) noexcept #else quint32 u; memcpy(&u, &f, sizeof(quint32)); - b16 = quint16(basetable[(u >> 23) & 0x1ff] - + ((u & 0x007fffff) >> shifttable[(u >> 23) & 0x1ff])); + const quint32 signAndExp = u >> 23; + const quint32 base = basetable[signAndExp]; + const quint32 shift = shifttable[signAndExp]; + quint32 mantissa = (u & 0x007fffff); + if ((signAndExp & 0xff) == 0xff) { + if (mantissa) // keep nan from truncating to inf + mantissa = qMax(1U << shift, mantissa); + } else { + mantissa += (1U << (shift - 1)) - 1; // rounding + } + + // We use add as the mantissa may overflow causing + // the exp part to shift exactly one value. + b16 = quint16(base + (mantissa >> shift)); #endif } QT_WARNING_POP |