/ C library -- gtty / error = gtty(filep, ttyvec); / filep is descriptor of open tty / ttyvec[0, 1, 2] correspond to args of gtty .globl _gtty, cerror _gtty: mov r5,-(sp) mov sp,r5 mov 4(r5),r0 mov 6(r5),0f sys 0; 9f bec 1f jmp cerror 1: clr r0 mov (sp)+,r5 rts pc .data 9: sys gtty; 0:..