RCA 301 Programmer's Reference Manual
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7 Tape Read Reverse Simultaneous (RRS)General DescriptionThis instruction transfers a series of consecutive characters from magnetic tape or punched paper tape intothe HSM. Transfer from tape begins with the first character following a gap and ends when the next gap is sensedor the specified HSM area is filled. Though the tape moves in reverse, the characters will be placed in their properrelative position within HSM. This instruction operates in the Simultaneous Mode.FormatOperation — 7N — Identification character of Tape Station or Paper Tape Reader. (See Appendix G.)A Address — Address of HSM location to receive the first character read from tape.B Address — Address of HSM location to receive the last character read from tape.Direction of OperationRight to left.Direction of Tape MotionMagnetic tape moves in a reverse direction. Paper tape will move in the forward direction but characters readfrom paper tape are placed in memory from right to left.Outline of OperationInitially this instruction is staticized in the Normal Mode. If the Simultaneous Mode is free and the SMDIbutton is not on, the contents of the NOR, N, A, and B Registers are transferred to the SOR, M, S, and T Registersrespectively, and this instruction is executed in the Simultaneous Mode. This instruction sends a start signal to theinput unit specified by the contents of the M Register. After a gap is passed on magnetic tape, the first characteris placed in the input buffer, and this instruction operates in the following cycle:The character in the input buffer is transferred to the HSM location specified by the S Register. The contentsof the S Register are decremented by one. If a gap is passed in sequence, the instruction terminates. If the comparisonproves equal and a gap is not passed, the instruction terminates, and tape movement continues to gap. If thecomparison proved not equal and a gap is not passed, the cycle is repeated.If an EF or ED alone is read from magnetic tape, the EF/ED Simultaneous Indicator is set. The EF/EDSimultaneous Indicator is not set when reading from paper tape. If SMDI is set, the EF/ED Normal Indicator willbe set.If ETW is passed the ETW flip-flop is reset.Final Register Contents(S)t = Address of location one to the left of the last character read.(T)t = (B)iTimingHi-Data tapes, Model 381, are read at the rate of 10 KC.Hi-Data tapes, Model 382, are read at the rate of 30 KC.Paper tape is read at the rate of up to 1000 characters per second.The tape station attached to the Tape Adapter or Dual Tape Channel is read at the rate of 33.3 KC if it is aModel 581 Tape Station or 66.7 KC if it is a Model 582 Tape Station.IX-9 |
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