mikkksa / pdp-11

PDP-11 Emulator

Usage

Emulator

1. make
2. ./pdp.bin *name of program to execute*.

Ex: ./pdp.bin programs/logo

Alternatively, for build one can use CMake with CMakeLists.txt present.

Bytecode generator

1. cd assembler
2. make
3. ./asm *path to assembler code* *filename*.

Ex: ./asm ../programs/white_screen.s white_screen

GUI

Graphical Interface contains:

• The values of the general purpose registers, as well as Processor Status Word flags (N, Z, V, C).
• Number of CPU ticks from the start of the program execution, with and without pipeline optimisation.
• Disassembly and byte code, showing the instructions executed so far.
• The "Step" mode, allowing to execute instructions one by one.
• Two modes for a program execution: the "Start" mode for the slow and the "Execute" mode for the quick execution.

Overall emulator architecture

• emulator class is designed for the pipeline cycle execution (in our case, one cycle consists of fetch, decode, load operands, execute). Moreover, it's used for the communication with the GUI, providing the information about memory, registers and the progress of the program execution.
• instructions contains the global instruction table and instruction callbacks.
• memory contains registers and the continuous space of RAM, video memory and ROM (in this exact order). The sizes of these parts of memory can be modyfied in emulator/params.hpp.
• pipeline counts the CPU ticks it could spend executing the instructions in two ways:
  • one by one
  • parallelizing with the pipeline.

The number of ticks one pipeline stage occupies can be modyfied in emulator/params.hpp.

Authors

• GUI - @detininroman
• Execution cycle, memory, simple pipeline - @pekashy
• Commands, bytecode generator, example programs - @terana
• Overall architecture - @FflushLife