diff options
Diffstat (limited to 'compiler-rt/lib/builtins/ppc/fixtfdi.c')
| -rw-r--r-- | compiler-rt/lib/builtins/ppc/fixtfdi.c | 185 |
1 files changed, 92 insertions, 93 deletions
diff --git a/compiler-rt/lib/builtins/ppc/fixtfdi.c b/compiler-rt/lib/builtins/ppc/fixtfdi.c index 914d7af9bb1..d33194a68f2 100644 --- a/compiler-rt/lib/builtins/ppc/fixtfdi.c +++ b/compiler-rt/lib/builtins/ppc/fixtfdi.c @@ -7,99 +7,98 @@ * This file implements the PowerPC 128-bit double-double -> int64_t conversion */ -#include "DD.h" #include "../int_math.h" +#include "DD.h" + +uint64_t __fixtfdi(long double input) { + const DD x = {.ld = input}; + const doublebits hibits = {.d = x.s.hi}; + + const uint32_t absHighWord = + (uint32_t)(hibits.x >> 32) & UINT32_C(0x7fffffff); + const uint32_t absHighWordMinusOne = absHighWord - UINT32_C(0x3ff00000); + + /* If (1.0 - tiny) <= input < 0x1.0p63: */ + if (UINT32_C(0x03f00000) > absHighWordMinusOne) { + /* Do an unsigned conversion of the absolute value, then restore the sign. + */ + const int unbiasedHeadExponent = absHighWordMinusOne >> 20; + + int64_t result = hibits.x & INT64_C(0x000fffffffffffff); /* mantissa(hi) */ + result |= INT64_C(0x0010000000000000); /* matissa(hi) with implicit bit */ + result <<= 10; /* mantissa(hi) with one zero preceding bit. */ + + const int64_t hiNegationMask = ((int64_t)(hibits.x)) >> 63; + + /* 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.s.lo}; + int64_t tailMantissa = lobits.x & INT64_C(0x000fffffffffffff); + tailMantissa |= INT64_C(0x0010000000000000); + + /* At this point we have the mantissa of |tail| */ + /* We need to negate it if head and tail have different signs. */ + const int64_t loNegationMask = ((int64_t)(lobits.x)) >> 63; + const int64_t negationMask = loNegationMask ^ hiNegationMask; + tailMantissa = (tailMantissa ^ negationMask) - negationMask; + + /* 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 10 that we shifted the head mantissa by. + */ + tailMantissa >>= + (unbiasedHeadExponent - (biasedTailExponent - (1023 - 10))); + + result += tailMantissa; + } + + result >>= (62 - unbiasedHeadExponent); + + /* Restore the sign of the result and return */ + result = (result ^ hiNegationMask) - hiNegationMask; + return result; + } + + /* Edge cases handled here: */ + + /* |x| < 1, result is zero. */ + if (1.0 > crt_fabs(x.s.hi)) + return INT64_C(0); + + /* x very close to INT64_MIN, care must be taken to see which side we are on. + */ + if (x.s.hi == -0x1.0p63) { + + int64_t result = INT64_MIN; + + if (0.0 < x.s.lo) { + /* If the tail is positive, the correct result is something other than + * INT64_MIN. we'll need to figure out what it is. + */ + + const doublebits lobits = {.d = x.s.lo}; + int64_t tailMantissa = lobits.x & INT64_C(0x000fffffffffffff); + tailMantissa |= INT64_C(0x0010000000000000); + + /* Now we negate the tailMantissa */ + tailMantissa = (tailMantissa ^ INT64_C(-1)) + INT64_C(1); + + /* And shift it by the appropriate amount */ + const int biasedTailExponent = (int)(lobits.x >> 52) & 0x7ff; + tailMantissa >>= 1075 - biasedTailExponent; + + result -= tailMantissa; + } + + return result; + } -uint64_t __fixtfdi(long double input) -{ - const DD x = { .ld = input }; - const doublebits hibits = { .d = x.s.hi }; - - const uint32_t absHighWord = (uint32_t)(hibits.x >> 32) & UINT32_C(0x7fffffff); - const uint32_t absHighWordMinusOne = absHighWord - UINT32_C(0x3ff00000); - - /* If (1.0 - tiny) <= input < 0x1.0p63: */ - if (UINT32_C(0x03f00000) > absHighWordMinusOne) - { - /* Do an unsigned conversion of the absolute value, then restore the sign. */ - const int unbiasedHeadExponent = absHighWordMinusOne >> 20; - - int64_t result = hibits.x & INT64_C(0x000fffffffffffff); /* mantissa(hi) */ - result |= INT64_C(0x0010000000000000); /* matissa(hi) with implicit bit */ - result <<= 10; /* mantissa(hi) with one zero preceding bit. */ - - const int64_t hiNegationMask = ((int64_t)(hibits.x)) >> 63; - - /* 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.s.lo }; - int64_t tailMantissa = lobits.x & INT64_C(0x000fffffffffffff); - tailMantissa |= INT64_C(0x0010000000000000); - - /* At this point we have the mantissa of |tail| */ - /* We need to negate it if head and tail have different signs. */ - const int64_t loNegationMask = ((int64_t)(lobits.x)) >> 63; - const int64_t negationMask = loNegationMask ^ hiNegationMask; - tailMantissa = (tailMantissa ^ negationMask) - negationMask; - - /* 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 10 that we shifted the head mantissa by. - */ - tailMantissa >>= (unbiasedHeadExponent - (biasedTailExponent - (1023 - 10))); - - result += tailMantissa; - } - - result >>= (62 - unbiasedHeadExponent); - - /* Restore the sign of the result and return */ - result = (result ^ hiNegationMask) - hiNegationMask; - return result; - - } - - /* Edge cases handled here: */ - - /* |x| < 1, result is zero. */ - if (1.0 > crt_fabs(x.s.hi)) - return INT64_C(0); - - /* x very close to INT64_MIN, care must be taken to see which side we are on. */ - if (x.s.hi == -0x1.0p63) { - - int64_t result = INT64_MIN; - - if (0.0 < x.s.lo) - { - /* If the tail is positive, the correct result is something other than INT64_MIN. - * we'll need to figure out what it is. - */ - - const doublebits lobits = { .d = x.s.lo }; - int64_t tailMantissa = lobits.x & INT64_C(0x000fffffffffffff); - tailMantissa |= INT64_C(0x0010000000000000); - - /* Now we negate the tailMantissa */ - tailMantissa = (tailMantissa ^ INT64_C(-1)) + INT64_C(1); - - /* And shift it by the appropriate amount */ - const int biasedTailExponent = (int)(lobits.x >> 52) & 0x7ff; - tailMantissa >>= 1075 - biasedTailExponent; - - result -= tailMantissa; - } - - return result; - } - - /* Signed overflows, infinities, and NaNs */ - if (x.s.hi > 0.0) - return INT64_MAX; - else - return INT64_MIN; + /* Signed overflows, infinities, and NaNs */ + if (x.s.hi > 0.0) + return INT64_MAX; + else + return INT64_MIN; } |
