Wire up three real, public-domain ROMs from the silicon era and prove
they boot end-to-end on the clean-room chip implementations. Each
test reads a separate well-known boot artifact:
* Busicom 141-PF firmware (4004, 1 KB, Intel PD 2009)
Wires real 4004 + real 4002 chips on the multiplexed nibble bus.
Toggles TEST every ~400 phases to mimic the printer-drum encoder
pulse the firmware polls. Asserts >2000 opcode fetches, >15 unique
PC addresses, and >100 CMROM strobes.
* Palo Alto Tiny BASIC v2 (8080, 1.9 KB, Wang 1976 PD)
CPUville port loaded from Intel HEX. Fake polled 8251 UART at port
0x02 (data) / 0x03 (status). Asserts the captured TX stream
contains the BASIC "OK" prompt — proving the interpreter reached
its REPL.
* Galaksija ROM A (Z80, 4 KB, Voja Antonić PD 1984)
ROM A+B at 0x0000..0x1FFF, system RAM at 0x2000..0x3FFF. Asserts
PC visits the JP target 0x03DA from reset and the ASCII "READY"
prompt appears in RAM after init.
ROMs are downloaded to roms/{4004,8080,z80}/ and gitignored — the
tests skip cleanly when the binaries are absent. License-clean: no
GPL ROMs, all PD by upstream provenance.
Total: 126 → 129 passing, 0 todo, 0 failed; 19 → 22 test files.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Convert the last outstanding it.todo (4004 Busicom-style program)
into a passing integration test. The Busicom 141-PF firmware itself
isn't available in-environment, so this is an original demo that
exercises the same bus paths the firmware used:
CLB ; loop: SRC P0 ; WMP ; IAC ; JUN loop
Wires real 4004 + real 4002 chips on a shared D bus and uses the
JS-side nibble-bus driver to feed the 6-byte program. The 4002's
O0..O3 output port blinks through 0, 1, 2, 3, …, F, 0, … each
iteration. Test asserts the first 6 distinct outputs are 0..5 —
proving the loop iterates and the output port reflects each WMP-
driven ACC update faithfully.
Final state: 126 tests, 126 passing, 0 todo, 0 failed.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Convert 7 outstanding it.todo markers into actual passing tests now
that the chips and bus infrastructure can support them:
- 4004 LDM: ACC observed via SRC + WMP X2 bus drive
- 4004 FIM: register pair observed via SRC X2/X3 nibble drives
- 8080 hand-built loop: LXI/MVI/INR/DCR/JNZ decrements counter
- Z80 IM 2: vector table at I:00 → ISR via INT̅ low
- 8086 1 MB wrap: DS=0xFFFF + offset 0x11 lands at physical 0x00001
- 8086 ALE pulse: counts ALE rising edges per bus cycle
- 8086 AD release: external drive sticks during T2 (chip released)
- 8086 hello-world: 5 MOV BYTE [imm], imm writes to memory-mapped
"UART" at DS:0x9000; bus capture + RAM peek verify "Hello"
Plus: remove redundant 8080 CPUDIAG and Z80 ZEXDOC todos — the
actual end-to-end runs already pass in dedicated cpudiag.test.js
and zexdoc.test.js files.
Suite is now 125/126 passing, 1 todo (Busicom 141-PF demo, awaiting
firmware ROM), 0 failed.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
The 4004 chip now drives or samples the multiplexed nibble bus during
X2/X3 with CM-RAM (or CM-ROM) strobed for SRC, WRM, WMP, WRR, WPM,
WR0..3, SBM, RDM, RDR, ADM, RD0..3 — completing the I/O group that
was previously stubbed. The 4002 RAM chip is rewritten with a
phase-count-based timing model that samples the opcode at M1/M2 and
drives or latches the bus at the correct frame relative to the 4004's
drives.
Two new integration tests in 4002-ram.test.js wire a real 4004 + 4002
on the same board and prove the round-trip:
1. SRC P0 + LDM 3 + WMP — 4002 output port goes to 3.
2. SRC P0 + WRM 5 + CLB + RDM + WMP — 4002 output port goes to 5
(proves both write and read paths through the bus).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
All 46 4004 instructions implemented per MCS-4 manual ([M4] Table V):
- ALU: NOP, INC Rn, ADD/SUB Rn, LD/XCH Rn, IAC/DAC, RAL/RAR, CMA, CMC,
STC, CLB, CLC, TCC, TCS, DAA, KBP
- Memory/IO: SRC Pn (no-op stub), I/O group (WRM/WMP/WRR/WPM/WR0..3,
RDM/RDR/ADM/RD0..3, SBM) all decoded; RAM-side effects stubbed
pending real 4001/4002 chips
- Control flow: JUN (12-bit jump), JMS (push+jump), BBL (pop+ACC),
JCN with full C1/C2/C3/C4 condition logic, ISZ in-page branch,
FIM (load reg pair), FIN/JIN (indirect via P0)
- DCL: load CMRAM bank select
Plus a Bus4004 helper class in 4004.test.js that mirrors a 4001 ROM
chip — pre-drives D0..D3 with the appropriate nibble during M1/M2,
tracks observed PC via the chip's A1/A2/A3 address-bus drives. This
mechanism lets the test feed arbitrary opcode streams without
needing a separate 4001 ROM chip on the canvas.
5 new ISA tests promoted from it.todo to passing:
- NOP advances PC by 1
- JUN jumps to 12-bit target
- JMS+BBL stack push/pop
- JCN with C4 jumps when TEST is logic-0
- JCN does not jump when condition false
3 it.todo remain: LDM, FIM, Busicom-style integration. These need
accumulator-state observability (a fake 4002 RAM via SRC+WRM) to
test, which is deferred.
Total test_intel: 52 passing (was 43), 0 failed, 25 todo.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
The two earliest commercial Intel CPUs as velxio custom chips:
- 4004.c (~150 LOC): 16-pin DIP, 8-phase frame (A1..X3), SYNC at A1
with PC nibble walk on D0..D3 (low-first per MCS-4 Fig. 2), CMROM
strobe during M1. ISA decoded as NOP for now — full 46-instruction
set deferred to ISA phase.
- 4040.c (~250 LOC): 24-pin DIP per MCS-40 pp. 1-5/1-6 (STP/STPA/INT/
INTA/CY/dual CMROM/dual standby Vdd). 4004-compatible bus + STP
latched at M2 → STPA asserts at X3 + INT forced JMS to PC=0x003.
14 new opcodes decoded as NOP for now.
Test refinements (analogous to bootCpu fix from 8080 work):
- bootChip no longer advances time post-RESET so first observed cycle
starts at A1 of cycle 0 with PC=0.
- SYNC sampler latches on first edge (was over-collecting on
subsequent SYNC pulses).
- 4040 test renamed STOP→STP, STOPACK→STPA per MCS-40 datasheet pin
names; added INTA, CY, VDD1, VDD2 pins; SYNC-stops assertion
removed (manual: STOP mode keeps clock and SYNC running).
Brings test_intel suite from 37 to 43 passing tests; 0 failures;
remaining 3 active are 8086 (deferred), 29 todo are intentional
deferred integration tests.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
David Montero