Crate cpu

Expand description

This crate decodes instructions and emulates the arithmetic unit, the exchange unit, memory and the CPU side of the I/O system.

All the work is done in non-blocking function calls into this library.

The modules within this crate do not directly map to the elements of the TX-2 machine.

TX-2 Element	Feature	Implementation
Control Element	Start/Stop control, CODABO, STARTOVER, Sequencing the stages of instructions	control
Control Element	Alarms	alarmunit
In/Out Element	All	io
Program Element	Sequence flags, Index register storage, Instruction decoding, Instruction, executrion, Deferred addressing	control
Program Element	Sequence selection and switching	control
Program Element	Registers N, P, Q, K	control
Program Element	Configuration memory	control
Program Element	Jumps	control
Arithmetic Element	Register A, B, C, D, Arithmetic operations,	control
Arithmetic Element	Registers Y and Z	Not yet implemented
Exchange Element	Load/store process	exchanger
Exchange Element	Register E	exchanger
Exchange Element	Register M	memory
Exchange Element	Quarter activity, subword form, sign extension	exchanger
In/Out Element	Connecting/disconnecting peripherals, raising the flag of sequences for which I/O is ready	io
Memory Element	Memory storage	exchanger
Console	Toggle Start Point Register	control::ControlUnit

Modules§

alarm 🔒: TX-2 alarms.
alarmunit 🔒: The TX-2 can “mask” some alarms, and whether or not this is happening is controlled by the AlarmUnit.
bugreport 🔒: Generate bug-report URLs.
changelog 🔒: A collection of orderable values which the caller can efficiently drain in one go.
context 🔒: This module manages the context in which the emulator is performing a single operation.
control 🔒: Emulates the principal central components of the TX-2.
diagnostics 🔒: Diagnostic information for log messages and alarms.
event 🔒: Input and output events.
exchanger 🔒: The Exchange Element governs data exchange between memory (via the M register) and other parts of the central compute unit (including the arithmetic element) via the E register.
io 🔒: This module simulates the CPU behaviours which relate to I/O devices (connect/disconnect, the ways the IOS and TSD instructions with devices).
memory 🔒: This module emulates the TX-2’s STUV memory.
tx2 🔒: Emulation of the TX-2 computer.
types 🔒: Simple types used in several places in the crate.

Alarm: Describes an alarm which is active.
AlarmStatus: The status of an alarm.
Context: State shared between the emulator and the UI.
ControlRegisters: Registers from various elements of the TX-2.
ControlUnit: ControlUnit simulates the operation of the Control Element of the TX-2 computer.
DeviceManager: Manages a collection of devices. Does not actually correspond to a tangible physical component of the TX-2 system.
ExtendedConnectedUnitStatus: Status information for a unit which is actually connected.
ExtendedUnitState: The state of a unit (hardware belonging to a sequence).
MaskedWord: A value of which bits 0..width are significant (0 being the least significant bit). Hence a six-bit value would be MaskedWord { width: 6, value: u13!(0o77) }
MemoryConfiguration: MemoryConfiguration indicates how the emulated TX-2’s memory is configured.
MemoryUnit
Tx2: Tx2 emulates the TX-2 computer, with peripherals.
UnmaskedAlarm: Describes an alarm which is active and is not masked (meaning that it is actually firing).

AlarmDetails: AlarmsDetails variant names are from User’s Handbook section 5-2.2; full names are taken from section 10-2.5.1 (vol 2) of the Technical Manual.
AlarmKind: Describes the kinds of alarm that exist in the TX-2.
FlagChange: Signals that a flag has changed (and why).
InputEvent: An input event.
InputEventError: A failed input event.
InputFlagRaised: Indicates whether or not a unit’s input flag is raised.
OutputEvent: An output event.
PanicOnUnmaskedAlarm
ResetMode
RunMode
TransferMode: Determines how TSD instructions for Lincoln Writer seuenced behave.
UpdateE: Determines whether a memory operation updates the E register.