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Diffstat (limited to 'lib/ppc/floatditf.c')
-rw-r--r-- | lib/ppc/floatditf.c | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/lib/ppc/floatditf.c b/lib/ppc/floatditf.c new file mode 100644 index 000000000..081dc8cbe --- /dev/null +++ b/lib/ppc/floatditf.c @@ -0,0 +1,34 @@ +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. + +// long double __floatditf(long long x); +// This file implements the PowerPC long long -> long double conversion + +#include "DD.h" +#include <stdint.h> + +long double __floatditf(int64_t a) { + + static const double twop32 = 0x1.0p32; + static const double twop52 = 0x1.0p52; + + doublebits low = { .d = twop52 }; + low.x |= a & UINT64_C(0x00000000ffffffff); // 0x1.0p52 + low 32 bits of a. + + const double high_addend = (double)((int32_t)(a >> 32))*twop32 - twop52; + + // At this point, we have two double precision numbers + // high_addend and low.d, and we wish to return their sum + // as a canonicalized long double: + + // This implementation sets the inexact flag spuriously. + // This could be avoided, but at some substantial cost. + + DD result; + + result.hi = high_addend + low.d; + result.lo = (high_addend - result.hi) + low.d; + + return result.ld; + +} |