go/src/strconv/ftoaryu.go

// ryuFtoaFixed32 formats mant*(2^exp) with prec decimal digits.
func ryuFtoaFixed32(d *decimalSlice, mant uint32, exp int, prec int) { … }

// ryuFtoaFixed64 formats mant*(2^exp) with prec decimal digits.
func ryuFtoaFixed64(d *decimalSlice, mant uint64, exp int, prec int) { … }

var uint64pow10 …

// formatDecimal fills d with at most prec decimal digits
// of mantissa m. The boolean trunc indicates whether m
// is truncated compared to the original number being formatted.
func formatDecimal(d *decimalSlice, m uint64, trunc bool, roundUp bool, prec int) { … }

// ryuFtoaShortest formats mant*2^exp with prec decimal digits.
func ryuFtoaShortest(d *decimalSlice, mant uint64, exp int, flt *floatInfo) { … }

// mulByLog2Log10 returns math.Floor(x * log(2)/log(10)) for an integer x in
// the range -1600 <= x && x <= +1600.
//
// The range restriction lets us work in faster integer arithmetic instead of
// slower floating point arithmetic. Correctness is verified by unit tests.
func mulByLog2Log10(x int) int { … }

// mulByLog10Log2 returns math.Floor(x * log(10)/log(2)) for an integer x in
// the range -500 <= x && x <= +500.
//
// The range restriction lets us work in faster integer arithmetic instead of
// slower floating point arithmetic. Correctness is verified by unit tests.
func mulByLog10Log2(x int) int { … }

// computeBounds returns a floating-point vector (l, c, u)×2^e2
// where the mantissas are 55-bit (or 26-bit) integers, describing the interval
// represented by the input float64 or float32.
func computeBounds(mant uint64, exp int, flt *floatInfo) (lower, central, upper uint64, e2 int) { … }

func ryuDigits(d *decimalSlice, lower, central, upper uint64,
	c0, cup bool) { … }

// ryuDigits32 emits decimal digits for a number less than 1e9.
func ryuDigits32(d *decimalSlice, lower, central, upper uint32,
	c0, cup bool, endindex int) { … }

// mult64bitPow10 takes a floating-point input with a 25-bit
// mantissa and multiplies it with 10^q. The resulting mantissa
// is m*P >> 57 where P is a 64-bit element of the detailedPowersOfTen tables.
// It is typically 31 or 32-bit wide.
// The returned boolean is true if all trimmed bits were zero.
//
// That is:
//
//	m*2^e2 * round(10^q) = resM * 2^resE + ε
//	exact = ε == 0
func mult64bitPow10(m uint32, e2, q int) (resM uint32, resE int, exact bool) { … }

// mult128bitPow10 takes a floating-point input with a 55-bit
// mantissa and multiplies it with 10^q. The resulting mantissa
// is m*P >> 119 where P is a 128-bit element of the detailedPowersOfTen tables.
// It is typically 63 or 64-bit wide.
// The returned boolean is true is all trimmed bits were zero.
//
// That is:
//
//	m*2^e2 * round(10^q) = resM * 2^resE + ε
//	exact = ε == 0
func mult128bitPow10(m uint64, e2, q int) (resM uint64, resE int, exact bool) { … }

func divisibleByPower5(m uint64, k int) bool { … }

// divmod1e9 computes quotient and remainder of division by 1e9,
// avoiding runtime uint64 division on 32-bit platforms.
func divmod1e9(x uint64) (uint32, uint32) { … }