IEEE_MAP_UMZ
fp |= (sw & IEEE_MAP_UMZ ? FPCR_UNDZ | FPCR_UNFD : 0);
sw |= (fp >> 47) & IEEE_MAP_UMZ;
#define IEEE_MAP_MASK (IEEE_MAP_DMZ | IEEE_MAP_UMZ)
if ((_fex & FP_EX_UNDERFLOW) && (swcr & IEEE_MAP_UMZ))
if ((_fex & FP_EX_UNDERFLOW) && (swcr & IEEE_MAP_UMZ))