pio2_2t
pio2_2t = 2.0670321098263988236496903051604844e-43L, /* 0x127044533e63a0105df531d89cd91.0p-254 */
w = fn*pio2_2t-((t-r)-w);
pio2_2t = 6.36831716351095013979e-25L, /* 0xc51701b839a25205.0p-144 */
w = fn*pio2_2t-((t-r)-w);
w = fn*pio2_2t-((t-r)-w);
pio2_2t = 2.02226624879595063154e-21, /* 0x3BA3198A, 0x2E037073 */