M68K Interpreter Help

Panel Workspace

• Choose one to four columns, then add Screen, Code, Registers, Memory, Graphics, Sound, Seven-segment, combined Digital I/O and IRQ, or Help panels from the View menu.
• Drag a panel by its header to reorder it or move it between columns.
• Minimize retains a compact header, and close removes the panel from the current layout.
• Only the Screen marked Interactive owns keyboard, touch, focus, and terminal geometry. Click a passive Screen mirror to transfer ownership.
• The Layouts menu applies immutable built-in views and saves, restores, renames, or deletes personal views. The active draft resumes automatically after reload.
• On compact screens, the desktop layout is preserved and projected through a single-panel switcher.

Play Nibbles

Select nibbles.asm from the file explorer, press Run, then use W A S D, arrow keys, or keypad 4 5 6 8. Press Enter to confirm menus.

Reset clears the current emulator session and terminal so the loaded program can be launched again from a clean state.

The IDE composes a strict byte-addressed CPU model with an independent machine profile. The Easy68K machine layers terminal, trap, and trainer-board services onto any supported CPU.

MC68000, MC68010, and MC68020 Support

• Assembler compatibility includes standalone labels, END with an entry label, EQU, DC.B/W/L, DS.B/W/L, and character immediates.
• The strict core implements all 116 tracked MC68000 forms, all seven tracked MC68010-specific forms, and all 40 tracked MC68020 integer and protocol forms. Select the CPU independently of the machine profile.
• MC68010 mode exposes VBR, SFC, and DFC, VBR-relative vectors, format-aware exception frames, and restartable bus and address faults.
• MC68020 mode adds a 32-bit logical address space, full indexed addressing, three stack banks, cache controls, integer extensions, and generic coprocessor and module protocols.
• Canonical Easy68K compatibility includes terminal tasks 5, 6, 7, 9, and 11; graphics tasks 80 through 96; sound tasks 70 through 77; and environment task 33.
• Terminal rendering supports clear screen, cursor motion, carriage return, line feed, and ANSI SGR color and style sequences used by Nibbles.
• Memory-mapped Easy68K hardware includes independently addressable eight-byte seven-segment displays and digital I/O boards with shared switch and LED bytes, active-low buttons, and configurable 24-bit addresses.
• Level 1 through 7 autovector interrupts include SR masking, supervisor stack frames, automatic scheduling, and RTE.
• Graphics and Sound are first-class, duplicable workspace panels backed by worker-safe external surface stores.

Breakpoints and Step Debugging

• Click a Code line number or the dedicated debugger gutter, or press F9, to toggle a file-scoped source breakpoint. Right-click either gutter for breakpoint actions. Grey markers are unbound; yellow markers have a condition, hit count, or log message.
• The global toolbar provides F5 Continue, F6 Pause, Shift+F5 Stop, and Restart. The Code panel header provides F10 Step Over, F11 Step Into, Shift+F11 Step Out, Alt+F11 Step Back, and Ctrl or Command plus F10 Run to Cursor; narrow panels keep secondary actions in an overflow menu.
• The Debugger panel manages source, address, and label breakpoints, conditions, watches, write data breakpoints, call frames, and structured stop details.
• Execution never creates, reveals, focuses, minimizes, or reorders a panel. Add the Debugger panel or apply the Debug layout explicitly.
• Source edits preserve breakpoint definitions but can leave them unbound until a successful reassembly resolves the new instruction addresses.
• Step Back restores bounded logical CPU, memory, device, graphics, sound, and diagnostic history. Audio already heard cannot be reversed.

Known Limitations

• Easy68K sound file tasks operate on registered browser-safe assets rather than arbitrary host filesystem paths.
• Trainer board DUART routines are not implemented.
• Pin-level bus timing, arbitration, prefetch-stage attribution, and transparent loop-mode fetch suppression are outside the functionally complete CPU contract.
• Audio completion follows the browser audio backend and is not modeled in CPU cycles.
• MC68881 and MC68882 floating-point arithmetic and MC68851 page-table and MMU semantics are not included; MC68020 provides tested attachment and translation boundaries for them.