.TITLE R3BK .GLOBL .R3BK .MCALL .EXIT,.READW,.TLQ BLOCK: .BLKW 1 BUFFER: .BLKW 1 .R3BK: MOV R0,-(SP) TST BLOCK BGE READ .TLQ <.R3BK ERROR: NEG BLOCK NUMBER> .EXIT READ: .READW #LIST,#3,BUFFER,#256.,BLOCK MOV (SP)+,R0 BCS ERROR RETURN ERROR: CMPB 52,#1 BLT EOF BEQ HARD .TLQ <.R3BK ERROR: CHANNEL 3 NOT OPEN> .EXIT HARD: .TLQ <.R3BK: HARD ERROR, CHANNEL 3> .EXIT EOF: .TLQ SEC RETURN LIST: .WORD 0,0,0,256.,0 .END