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CI

OurPC

(picking a name is hard and is deferred for later)

The eventual goal(?) is to build a general-purpose processor integrated with simple input (e.g. buttons) and output devices (8x8 LED display).

Sample Programs

  • Ping Pong
    • Source: ping_pong.asm
    • Generate resolved assembly: python3 -m planner asm -r programs/ping_pong.asm [example]
    • Generate binary: python3 -m planner asm -b programs/ping_pong.asm [example]
    • Run on emulator: python3 -m planner compile_and_execute ping_pong
      • 16x8 LED display with W/S/Up/Down keyboard controller
      • image

Design

Specs

  • Memory Address Line: 16-bits (points to a byte)
  • Memory Value Line: 32-bits (4 bytes)
  • Max Memory: 64KB
  • Memory layout: here

Boot Sequence

  • programs/boot_sequence.asm binary (aka BROM) is mapped from address_line BOOTSEQUENCE_LOAD = 0x30
  • Memory Read
    • If BOOTSEQUENCE_ORG <= address_line < DEFAULT_PROGRAM_ORG, pulls value from BROM
    • Otherwise, pulls the value from RAM
  • Execution starts with PC at BOOTSEQUENCE_ORG = 0x34
  • BROM goal is to copy PROM to RAM at DEFAULT_PROGRAM_ORG = 0x80
  • Followed by jmp DEFAULT_PROGRAM_ORG

PROM

  • Programs like programs/ping_pong.asm are translated into binary and are referred to as PROM.
  • PROM is connected to as input-output device.
  • The equivalent program is loaded in RAM at DEFAULT_PROGRAM_ORG = 0x80, followed by execution after boot sequence.