SG-1000 Emulator + Z80 CPU Test Suite

📁 Load ROM

Speed: Vol:

P1: ← ↑ ↓ → = D-Pad | Z = Btn1 | X = Btn2 | Enter = Pause

P2: W/A/S/D = D-Pad | Q = Btn1 | E = Btn2 | R = Pause/Reset

🔧 Debug Panel ▼

CPU Registers cpu/z80.js

Flags

VDP Registers vdp/tms9918a.js

Disassembly debug/disassembler.js

Breakpoint debug/debugState.js

No breakpoint

🔒 ROM Protection

Make ROM read-only

🔒 ROM is read-only

💀 Memory Corruption

Amount:

Ready to corrupt...

Memory Viewer memory/memoryMap.js

🧪 Z80 CPU Test Suite cpu-tests/

Validate Z80 CPU accuracy using standard CP/M-based test ROMs. The test harness uses a flat 64KB memory model with BDOS call traps, completely independent of the SG-1000 memory map.

Load Test ROMs cpu-tests/roms/

📁 Load prelim.com Not loaded

📁 Load zexdoc.cim Not loaded

📁 Load zexall.cim Not loaded

Test Results cpu-tests/testRunner.js

Test Status Cycles Expected Diff Instructions

prelim.com — — 8,721 — —

zexdoc.cim — — 46,734,978,649 — —

zexall.cim — — 46,734,978,649 — —

Test Console Output cpu-tests/testHarness.js

Architecture Notes

┌─────────────────────────────────────────────────┐
│  cpu-tests/testHarness.js — TestIO              │
│  ┌───────────────────────────────────────────┐  │
│  │  Flat 64KB Memory (Uint8Array(0x10000))   │  │
│  │  No mapping, no mirrors, no VDP/PSG       │  │
│  │  readByte(addr) / writeByte(addr, val)    │  │
│  └───────────────────────────────────────────┘  │
│                                                 │
│  CP/M BDOS Trap Mechanism:                      │
│  0x0000: OUT (0),A  → testFinished = true       │
│  0x0005: IN A,(0)   → BDOS console output       │
│  0x0007: RET        → return to caller          │
│                                                 │
│  Port 0 Intercept:                              │
│  OUT → program exit   IN → BDOS call (C reg)    │
│  C=2: print char(E)  C=9: print string at DE    │
│                                                 │
│  ROM loaded at 0x0100 (CP/M .COM convention)    │
│  CPU.pc starts at 0x0100                        │
└─────────────────────────────────────────────────┘

Z80 CPU (cpu/z80.js) uses pluggable I/O interface:
  • SG-1000 mode → memory/memoryMap.js + io/ports.js
  • Test mode    → cpu-tests/testHarness.js (TestIO)

No ROM Loaded 0 FPS Cycles: 0 Mode: -- ROM: 32KB | Cart RAM: 8KB | Sys RAM: 1KB (mirrored)