diff options
Diffstat (limited to 'libdecnumber')
| -rw-r--r-- | libdecnumber/decContext.c | 7 | ||||
| -rw-r--r-- | libdecnumber/decNumber.c | 95 |
2 files changed, 99 insertions, 3 deletions
diff --git a/libdecnumber/decContext.c b/libdecnumber/decContext.c index 7d97a65ac5..1956edf0a7 100644 --- a/libdecnumber/decContext.c +++ b/libdecnumber/decContext.c @@ -53,12 +53,13 @@ static const Flag *mfctop=(Flag *)&mfcone; /* -> top byte */ const uByte DECSTICKYTAB[10]={1,1,2,3,4,6,6,7,8,9}; /* used if sticky */ /* ------------------------------------------------------------------ */ -/* Powers of ten (powers[n]==10**n, 0<=n<=9) */ +/* Powers of ten (powers[n]==10**n, 0<=n<=19) */ /* ------------------------------------------------------------------ */ -const uLong DECPOWERS[19] = {1, 10, 100, 1000, 10000, 100000, 1000000, +const uLong DECPOWERS[20] = {1, 10, 100, 1000, 10000, 100000, 1000000, 10000000, 100000000, 1000000000, 10000000000ULL, 100000000000ULL, 1000000000000ULL, 10000000000000ULL, 100000000000000ULL, 1000000000000000ULL, - 10000000000000000ULL, 100000000000000000ULL, 1000000000000000000ULL, }; + 10000000000000000ULL, 100000000000000000ULL, 1000000000000000000ULL, + 10000000000000000000ULL,}; /* ------------------------------------------------------------------ */ /* decContextClearStatus -- clear bits in current status */ diff --git a/libdecnumber/decNumber.c b/libdecnumber/decNumber.c index d7716ce175..31282adafd 100644 --- a/libdecnumber/decNumber.c +++ b/libdecnumber/decNumber.c @@ -264,6 +264,7 @@ static decNumber * decTrim(decNumber *, decContext *, Flag, Int *); static Int decUnitAddSub(const Unit *, Int, const Unit *, Int, Int, Unit *, Int); static Int decUnitCompare(const Unit *, Int, const Unit *, Int, Int); +static bool mulUInt128ByPowOf10(uLong *, uLong *, uInt); #if !DECSUBSET /* decFinish == decFinalize when no subset arithmetic needed */ @@ -542,6 +543,68 @@ Invalid: return 0; } /* decNumberIntegralToInt64 */ +/* ------------------------------------------------------------------ */ +/* decNumberIntegralToInt128 -- conversion to int128 */ +/* */ +/* dn is the decNumber to convert. dn is assumed to have been */ +/* rounded to a floating point integer value. */ +/* set is the context for reporting errors */ +/* returns the converted decNumber via plow and phigh */ +/* */ +/* Invalid is set if the decNumber is a NaN, Infinite or is out of */ +/* range for a signed 128 bit integer. */ +/* ------------------------------------------------------------------ */ + +void decNumberIntegralToInt128(const decNumber *dn, decContext *set, + uint64_t *plow, uint64_t *phigh) +{ + int d; /* work */ + const Unit *up; /* .. */ + uint64_t lo = 0, hi = 0; + + if (decNumberIsSpecial(dn) || (dn->exponent < 0) || + (dn->digits + dn->exponent > 39)) { + goto Invalid; + } + + up = dn->lsu; /* -> lsu */ + + for (d = (dn->digits - 1) / DECDPUN; d >= 0; d--) { + if (mulu128(&lo, &hi, DECDPUNMAX + 1)) { + /* overflow */ + goto Invalid; + } + if (uadd64_overflow(lo, up[d], &lo)) { + if (uadd64_overflow(hi, 1, &hi)) { + /* overflow */ + goto Invalid; + } + } + } + + if (mulUInt128ByPowOf10(&lo, &hi, dn->exponent)) { + /* overflow */ + goto Invalid; + } + + if (decNumberIsNegative(dn)) { + if (lo == 0) { + *phigh = -hi; + *plow = 0; + } else { + *phigh = ~hi; + *plow = -lo; + } + } else { + *plow = lo; + *phigh = hi; + } + + return; + +Invalid: + decContextSetStatus(set, DEC_Invalid_operation); +} /* decNumberIntegralToInt128 */ /* ------------------------------------------------------------------ */ /* to-scientific-string -- conversion to numeric string */ @@ -7885,6 +7948,38 @@ static Int decGetDigits(Unit *uar, Int len) { return digits; } /* decGetDigits */ +/* ------------------------------------------------------------------ */ +/* mulUInt128ByPowOf10 -- multiply a 128-bit unsigned integer by a */ +/* power of 10. */ +/* */ +/* The 128-bit factor composed of plow and phigh is multiplied */ +/* by 10^exp. */ +/* */ +/* plow pointer to the low 64 bits of the first factor */ +/* phigh pointer to the high 64 bits of the first factor */ +/* exp the exponent of the power of 10 of the second factor */ +/* */ +/* If the result fits in 128 bits, returns false and the */ +/* multiplication result through plow and phigh. */ +/* Otherwise, returns true. */ +/* ------------------------------------------------------------------ */ +static bool mulUInt128ByPowOf10(uLong *plow, uLong *phigh, uInt pow10) +{ + while (pow10 >= ARRAY_SIZE(powers)) { + if (mulu128(plow, phigh, powers[ARRAY_SIZE(powers) - 1])) { + /* Overflow */ + return true; + } + pow10 -= ARRAY_SIZE(powers) - 1; + } + + if (pow10 > 0) { + return mulu128(plow, phigh, powers[pow10]); + } else { + return false; + } +} + #if DECTRACE | DECCHECK /* ------------------------------------------------------------------ */ /* decNumberShow -- display a number [debug aid] */ |