A Domain-Specific Architecture for Elementary Function Evaluation

Table 2

(a) Values returned by lookup instructions, for IEEE floating-point inputs , which rounds to the nearest integer . In case of exp2, inputs <−1074 are treated as and inputs >1024 are treated as . For inputs <−1022, we create subnormal numbers for the second lookup. (b, c) Treatment of exceptional values by fmaX follows from that of addition and multiplication. The first argument is given by the row and the second by the column. Conventional treatment is indicated by a “” and unusual handling by specific constant values.

(a)

Function	Finite > 0				Finite < 0
recip	,	0, 0	0, 0	0,	,
sqrt	,	0,	0, NaN	0, 0	0, NaN
rsqrt	,	0, 0	0, NaN	0,	0, NaN
log2	,	0,	0, NaN	0,	0, NaN
exp2	,	0,	NaN, 0	0, 1	,

(b)

	Finite			NaN
Finite
NaN

(c)

	Finite			NaN
Finite ≠ 0		2	2	2
NaN0
NaN1
NaN2
NaN3