const math.fracMask

5 uses

	math (current package)
		bits.go#L16: 	fracMask = 1<<shift - 1
		floor.go#L116: 		bits &^= fracMask >> e
		floor.go#L149: 		bits &^= fracMask >> e
		floor.go#L150: 	} else if e == bias-1 && bits&fracMask != 0 {
		fma.go#L79: 	mantissa = b & fracMask