Function reg_32_to_8 

pub unsafe extern "C" fn reg_32_to_8(reg: reg_id_t) -> reg_id_t

Assumes that \p reg is a DR_REG_ 32-bit register constant. Returns the 8-bit version of \p reg (the least significant byte: DR_REG_AL instead of DR_REG_AH if passed DR_REG_EAX, e.g.). For 32-bit DR builds, returns DR_REG_NULL if passed DR_REG_ESP, DR_REG_EBP, DR_REG_ESI, or DR_REG_EDI. \note x86-only.