shithub: mc

ref: 60bc966a9154e134e143c7cfeb001a93761e2d5e
dir: /lib/std/fltbits.myr/

pkg std =
	const flt64bits	: (flt : flt64 -> int64)
	const flt32bits	: (flt : flt32 -> int32)
	const flt64frombits	: (bits : uint64 -> flt64)
	const flt32frombits	: (bits : uint32 -> flt32)
	const flt64explode	: (flt : flt64 -> (bool, int64, int64))
	const flt32explode	: (flt : flt32 -> (bool, int32, int32))
;;

const flt64bits	= {flt;	-> (&flt castto(int64#))#}
const flt32bits	= {flt;	-> (&flt castto(int32#))#}
const flt64frombits	= {bits;	-> (&bits castto(flt64#))#}
const flt32frombits	= {bits;	-> (&bits castto(flt32#))#}

const flt64explode = {flt
	var bits, isneg, mant, exp

	bits = flt64bits(flt)
	isneg = (bits >> 63) != 0  	/* msb is sign bit */
	exp = (bits >> 52) & 0x7ff 	/* exp is in bits [52..63] */
	mant = bits & ((1l << 52) - 1) /* msb is in bits [..51] */

	/* add back the implicit bit if this is not a denormal */
	if exp != 0
		mant |= 1l << 52
	else
		exp = 1
	;;
	/*
	   adjust for exponent bias. nb: because we are
	   treating the mantissa as m.0 instead of 0.m,
	   our exponent bias needs to be offset by the
	   size of m
	*/
	-> (isneg, mant, exp)
}

const flt32explode = {flt
	var bits, isneg, mant, exp

	bits = flt32bits(flt)
	isneg = (bits >> 31) != 0  	/* msb is sign bit */
	exp = (bits >> 22) & 0xff 	/* exp is in bits [23..30] */
	mant = bits & ((1 << 22) - 1) /* msb is in bits [0..22] */

	/* add back the implicit bit if this is not a denormal */
	if exp != 0
		mant |= 1 << 22
	else
		exp = 1
	;;
	/*
	   adjust for exponent bias. nb: because we are
	   treating the mantissa as m.0 instead of 0.m,
	   our exponent bias needs to be offset by the
	   size of m
	*/
	-> (isneg, mant, exp)
}