Development Milestones
Daphnis documents verified milestones achieved through reproducible experimental runs and synthetic assertions. Entries explicitly differentiate between implemented infrastructure and authentic BIOS runtime observations.
Original European Sega Saturn BIOS Execution
Demonstrated stable execution through the initial stages of the authentic European Sega Saturn retail BIOS ROM without synthetic shortcuts.
- ▸Authentic boot vector fetching from 0x00000000
- ▸Correct initialization of internal CPU registers and vector table
- ▸Safe stepping through early machine self-checks
Master SH-2 Architecture & Instruction Coverage
Developed an independent 32-bit RISC core supporting memory addressing modes, delay slot execution semantics, and exception dispatching.
- ▸Branch delay slot timing and status flag integrity
- ▸Arithmetic, logical, bitwise, and control instruction suites
- ▸Precise memory exception handling without host leaks
SMPC Handshake & Authentic INTBACK Interaction
Successfully handled asynchronous System Manager communications including continuous INTBACK commands required for peripheral and clock negotiation.
- ▸Command handshaking via IREG and OREG register sets
- ▸Intback status and peripheral data packet reporting
- ▸Authentic system reset sequence handling
SCU Interrupt Arbiter & Peripheral Signaling
Implemented interrupt arbitration coordinating SMPC, VDP blanking triggers, and CD Block events according to hardware priority levels.
- ▸Interrupt mask register (IMS) and interrupt status register (IST) conformance
- ▸Multi-priority request resolution
CD Block Command Infrastructure & Buffer Partitioning
Constructed the CD Block controller communication engine, including command status registers, selector routing, and sector buffer data holding.
- ▸CR1-CR4 command and parameter transmission protocol
- ▸Status word generation adhering to hardware response timings
- ▸Sector buffer allocation and filter selector assignment
DiscImage FAD Mapping & Byte-for-Byte PAL Validation
Verified accurate physical sector conversion (FAD to MSF/LBA) and confirmed byte-for-byte exactness against original PAL media images.
- ▸Exact Frame Address (FAD) arithmetic matching optical lead-in offsets
- ▸Cross-validated sector extraction against reference physical dumps
- ▸Zero-copy read architecture abstractions
ISO 9660 Directory & File Identification
Integrated native ISO 9660 filesystem parsing directly within the disc subsystem to locate descriptors, path tables, and bootloader files.
- ▸Primary Volume Descriptor inspection
- ▸Path table parsing and directory record hierarchy traversal
- ▸Extraction of target binary locations and file lengths
Read File Observer & Transfer Instrumentation
Constructed non-invasive diagnostic tools monitoring sector acquisition, buffering states, PIO transfer queues, and transfer completion events.
- ▸Real-time logging of CD block state transitions
- ▸Observer hooks tracking buffer saturation and drain rates
- ▸Deterministic assertion suite for synthetic hardware test cases