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Diffstat (limited to 'lib/builtins/ppc/floatunditf.c')
| -rw-r--r-- | lib/builtins/ppc/floatunditf.c | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/lib/builtins/ppc/floatunditf.c b/lib/builtins/ppc/floatunditf.c new file mode 100644 index 000000000000..b12e1e738fd0 --- /dev/null +++ b/lib/builtins/ppc/floatunditf.c @@ -0,0 +1,41 @@ +/* This file is distributed under the University of Illinois Open Source + * License. See LICENSE.TXT for details. + */ + +/* long double __floatunditf(unsigned long long x); */ +/* This file implements the PowerPC unsigned long long -> long double conversion */ + +#include "DD.h" + +long double __floatunditf(uint64_t a) { + + /* Begins with an exact copy of the code from __floatundidf */ + + static const double twop52 = 0x1.0p52; + static const double twop84 = 0x1.0p84; + static const double twop84_plus_twop52 = 0x1.00000001p84; + + doublebits high = { .d = twop84 }; + doublebits low = { .d = twop52 }; + + high.x |= a >> 32; /* 0x1.0p84 + high 32 bits of a */ + low.x |= a & UINT64_C(0x00000000ffffffff); /* 0x1.0p52 + low 32 bits of a */ + + const double high_addend = high.d - twop84_plus_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.s.hi = high_addend + low.d; + result.s.lo = (high_addend - result.s.hi) + low.d; + + return result.ld; + +} |