clamp_val
val = clamp_val(mag, 0, negative ?
(clamp_val(((coeff) >> (32 - (fbits) - 3)) + 4, 0, 0xfff) & 0xff8)
u32 abs_coeff = clamp_val(CTM_COEFF_ABS(user_coeff), 0,
abs_coeff = clamp_val(abs_coeff, 0, CTM_COEFF_4_0 - 1);