diff options
Diffstat (limited to 'gcc/config/s390/fixdfdi.h')
| -rw-r--r-- | gcc/config/s390/fixdfdi.h | 32 |
1 files changed, 19 insertions, 13 deletions
diff --git a/gcc/config/s390/fixdfdi.h b/gcc/config/s390/fixdfdi.h index fd12243a381..95a5eef0173 100644 --- a/gcc/config/s390/fixdfdi.h +++ b/gcc/config/s390/fixdfdi.h @@ -78,13 +78,15 @@ __fixunstfdi (long double a1) if ((EXPD(dl1) == 0x7fff) && !FRACD_ZERO_P (dl1)) return 0x0ULL; - /* If the upper ll part of the mantissa isn't - zeroed out after shifting the number would be to large. */ - if (exp >= -HIGH_LL_FRAC_BITS) - return 0xFFFFFFFFFFFFFFFFULL; - + /* One extra bit is needed for the unit bit which is appended by + MANTD_HIGH_LL on the left of the matissa. */ exp += HIGH_LL_FRAC_BITS + 1; + /* If the result would still need a left shift it will be to large + to be represented. */ + if (exp > 0) + return 0xFFFFFFFFFFFFFFFFULL; + l = MANTD_LOW_LL (dl1) >> (HIGH_LL_FRAC_BITS + 1) | MANTD_HIGH_LL (dl1) << (64 - (HIGH_LL_FRAC_BITS + 1)); @@ -118,7 +120,7 @@ union double_long { struct { SItype_x i[4]; /* 32 bit parts: 0 upper ... 3 lowest */ } l; - DItype_x ll[2]; /* 64 bit parts: 0 upper, 1 lower */ + UDItype_x ll[2]; /* 64 bit parts: 0 upper, 1 lower */ }; DItype_x __fixtfdi (long double a1); @@ -150,17 +152,21 @@ __fixtfdi (long double a1) if ((EXPD(dl1) == 0x7fff) && !FRACD_ZERO_P (dl1)) return 0x8000000000000000ULL; - /* If the upper ll part of the mantissa isn't - zeroed out after shifting the number would be to large. */ - if (exp >= -HIGH_LL_FRAC_BITS) + /* One extra bit is needed for the unit bit which is appended by + MANTD_HIGH_LL on the left of the matissa. */ + exp += HIGH_LL_FRAC_BITS + 1; + + /* If the result would still need a left shift it will be to large + to be represented. Compared to the unsigned variant we have to + take care that there is still space for the sign bit to be + applied. So we can only go on if there is a right-shift by one + or more. */ + if (exp >= 0) { - l = (long long)1 << 63; /* long int min */ + l = (long long)1 << 63; /* long long int min */ return SIGND (dl1) ? l : l - 1; } - /* The extra bit is needed for the sign bit. */ - exp += HIGH_LL_FRAC_BITS + 1; - l = MANTD_LOW_LL (dl1) >> (HIGH_LL_FRAC_BITS + 1) | MANTD_HIGH_LL (dl1) << (64 - (HIGH_LL_FRAC_BITS + 1)); |