HelenOS sources

pc_lpt_regs_t     106 uspace/drv/char/pc-lpt/pc-lpt.c 	rc = pio_enable((void *)res->base, sizeof(pc_lpt_regs_t),
pc_lpt_regs_t      68 uspace/drv/char/pc-lpt/pc-lpt.h 	pc_lpt_regs_t *regs;
HelenOS homepage, sources at GitHub