diff options
Diffstat (limited to 'lib/ppc/fixunstfdi.c')
| -rw-r--r-- | lib/ppc/fixunstfdi.c | 38 |
1 files changed, 20 insertions, 18 deletions
diff --git a/lib/ppc/fixunstfdi.c b/lib/ppc/fixunstfdi.c index 35ce3a91..1fb52488 100644 --- a/lib/ppc/fixunstfdi.c +++ b/lib/ppc/fixunstfdi.c @@ -1,8 +1,9 @@ -// This file is distributed under the University of Illinois Open Source -// License. See LICENSE.TXT for details. +/* This file is distributed under the University of Illinois Open Source + * License. See LICENSE.TXT for details. + */ -// uint64_t __fixunstfdi(long double x); -// This file implements the PowerPC 128-bit double-double -> uint64_t conversion +/* uint64_t __fixunstfdi(long double x); */ +/* This file implements the PowerPC 128-bit double-double -> uint64_t conversion */ #include "DD.h" #include <stdint.h> @@ -10,37 +11,38 @@ uint64_t __fixunstfdi(long double input) { const DD x = { .ld = input }; - const doublebits hibits = { .d = x.hi }; + const doublebits hibits = { .d = x.s.hi }; const uint32_t highWordMinusOne = (uint32_t)(hibits.x >> 32) - UINT32_C(0x3ff00000); - // If (1.0 - tiny) <= input < 0x1.0p64: + /* If (1.0 - tiny) <= input < 0x1.0p64: */ if (UINT32_C(0x04000000) > highWordMinusOne) { const int unbiasedHeadExponent = highWordMinusOne >> 20; - uint64_t result = hibits.x & UINT64_C(0x000fffffffffffff); // mantissa(hi) - result |= UINT64_C(0x0010000000000000); // matissa(hi) with implicit bit - result <<= 11; // mantissa(hi) left aligned in the int64 field. + uint64_t result = hibits.x & UINT64_C(0x000fffffffffffff); /* mantissa(hi) */ + result |= UINT64_C(0x0010000000000000); /* matissa(hi) with implicit bit */ + result <<= 11; /* mantissa(hi) left aligned in the int64 field. */ - // If the tail is non-zero, we need to patch in the tail bits. - if (0.0 != x.lo) + /* If the tail is non-zero, we need to patch in the tail bits. */ + if (0.0 != x.s.lo) { - const doublebits lobits = { .d = x.lo }; + const doublebits lobits = { .d = x.s.lo }; int64_t tailMantissa = lobits.x & INT64_C(0x000fffffffffffff); tailMantissa |= INT64_C(0x0010000000000000); - // At this point we have the mantissa of |tail| + /* At this point we have the mantissa of |tail| */ const int64_t negationMask = ((int64_t)(lobits.x)) >> 63; tailMantissa = (tailMantissa ^ negationMask) - negationMask; - // Now we have the mantissa of tail as a signed 2s-complement integer + /* Now we have the mantissa of tail as a signed 2s-complement integer */ const int biasedTailExponent = (int)(lobits.x >> 52) & 0x7ff; - // Shift the tail mantissa into the right position, accounting for the - // bias of 11 that we shifted the head mantissa by. + /* Shift the tail mantissa into the right position, accounting for the + * bias of 11 that we shifted the head mantissa by. + */ tailMantissa >>= (unbiasedHeadExponent - (biasedTailExponent - (1023 - 11))); result += tailMantissa; @@ -50,8 +52,8 @@ uint64_t __fixunstfdi(long double input) return result; } - // Edge cases are handled here, with saturation. - if (1.0 > x.hi) + /* Edge cases are handled here, with saturation. */ + if (1.0 > x.s.hi) return UINT64_C(0); else return UINT64_MAX; |