.TITLE CONS ; JEFFREY KODOSKY ARL NOV75 ; ; SUBR ; ENTRY: 2 ARGS ; ; EXIT: 1 ARG CONS[;] ; ERRORS: NONE ; CALLS: GETC, FETCH A FREE CELL ; R2,R3 PRESERVED .GLOBL CONS,ZCONS,QGETC CONS: QGETC ;GET AN EMPTY CELL MOV (R5)+,R0;POP IT MOV (R5)+,(R0)+ ;INSTALL CAR MOV @R5,@R0 ;INSTALL CDR TST -(R0) ;POINT BACK TO CAR MOV R0,@R5 ;RETURN CONS JMP @-(R4) ZCONS=.-CONS .END