FPGAでMC68LC040もどきを用意したので、CPU側からvirtioに見えるデバイスを用意して、NetBSD/virt68kを動かそうという試み（の途中）
- CPU：公開されている68020互換コアにPMMUやキャッシュを追加して、やや68040っぽく振る舞うように改造（しかけてたものが既にあった）
- FPU：未実装
- virtio：裏でRISC-V (VexRiscv) がI/Oプロセッサとして動いてそれっぽく見せる
- NetBSD/vrit68k：FPUの存在を前提にしているので、少しいじってm68k/fpeを有効に
- FPGA：diligent Arty A7-100T (AMD (XILINX) Artix 7)
- その他：680×0もRISC-VもLiteXの枠組みを使用
まだちゃんと使えるようにはなってないのと、ライセンス回り整理すると公開できない（？）感じなので、なんとかしたいところ。
__ _ __ _ __
/ / (_) /____ | |/_/
/ /__/ / __/ -_)> <
/____/_/\__/\__/_/|_|
Build your hardware, easily!
(c) Copyright 2012-2026 Enjoy-Digital
(c) Copyright 2007-2015 M-Labs
BIOS CRC passed (82f8e6a0)
LiteX git sha1: e4a641d39
--================ SoC =================--
CPU: VexRiscv @ 100MHz
BUS: wishbone 32-bit data/32-bit addr
CSR: 32-bit data big ordering
ROM: 64.0KiB
SRAM: 8.0KiB
L2: 8.0KiB
SDRAM: 256.0MiB 16-bit @ 800MT/s (CL-6 CWL-5)
MAIN RAM: 256.0MiB
--=========== Initialization ===========--
Ethernet init...
Local IP: 192.168.1.50
Initializing SDRAM @0x40000000...
Switching SDRAM to software control.
Read leveling:
m0, b00: |00000000000000000000000000000000| delays: -
m0, b01: |00000000000000000000000000000000| delays: -
m0, b02: |11111111111110000000000000000000| delays: 06+-06
m0, b03: |00000000000000001111111111111000| delays: 22+-06
m0, b04: |00000000000000000000000000000000| delays: -
m0, b05: |00000000000000000000000000000000| delays: -
m0, b06: |00000000000000000000000000000000| delays: -
m0, b07: |00000000000000000000000000000000| delays: -
best: m0, b03 delays: 22+-06
m1, b00: |00000000000000000000000000000000| delays: -
m1, b01: |00000000000000000000000000000000| delays: -
m1, b02: |11111111111110000000000000000000| delays: 06+-06
m1, b03: |00000000000000001111111111111000| delays: 22+-06
m1, b04: |00000000000000000000000000000000| delays: -
m1, b05: |00000000000000000000000000000000| delays: -
m1, b06: |00000000000000000000000000000000| delays: -
m1, b07: |00000000000000000000000000000000| delays: -
best: m1, b03 delays: 22+-06
Switching SDRAM to hardware control.
Memtest at 0x40000000 (2.0MiB)...
Write: 0x40000000-0x40200000 2.0MiB
Read: 0x40000000-0x40200000 2.0MiB
Memtest OK
Memspeed at 0x40000000 (Sequential, 2.0MiB)...
Write speed: 37.1MiB/s
Read speed: 48.7MiB/s
--================ Boot ================--
Booting from serial...
Press Q or ESC to abort boot completely.
sL5DdSMmkekro
Executing booted program at 0x4f000000
--============== Liftoff! ==============--
[iop] m68k-virtio IOP firmware
[iop] sdcard: no card (cd=1)
[iop] no boot image at 0x4f100000 and no bootable SD card
iop> load 6176768 254e1dcb
ready
load ok 6176768
iop> boot
[iop] virtio-blk: ramdisk, 2048 sectors
[iop] virtio-net: slirp (10.0.2.2), mac 52:54:00:12:34:56
[iop] m68k start: entry 00002000 bootinfo 0036fbe4 ram 240MB
[ 1.0000000] Initialized Goldfish TTY console @ 0xff008000
[ 1.0000000] Reserving RAM disk pages 0xef00000 - 0xeffffff from memory segment 0.
[ 1.0000000] Memory segment 0: addr=0x003b5000 size=0x0eb4b000
[ 1.0000000] Copyright (c) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003,
[ 1.0000000] 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013,
[ 1.0000000] 2014, 2015, 2016, 2017, 2018, 2019, 2020, 2021, 2022, 2023,
[ 1.0000000] 2024, 2025, 2026
[ 1.0000000] The NetBSD Foundation, Inc. All rights reserved.
[ 1.0000000] Copyright (c) 1982, 1986, 1989, 1991, 1993
[ 1.0000000] The Regents of the University of California. All rights reserved.
[ 1.0000000] NetBSD 11.0 (VIRT_FPGA) #3: Sat Oct 10 18:50:31 JST 2026
[ 1.0000000] est@ursula:/home/est/opt/build/netbsd-virt68k/obj/sys/arch/virt68k/compile/VIRT_FPGA
[ 1.0000000] Qemu 6.0.1: MC68040+MMU, 4k+4k on-chip physical I/D caches
[ 1.0000000] total memory = 240 MB
[ 1.0000000] avail memory = 229 MB
[ 1.0000000] mainbus0 (root)
[ 1.0000000] gfpic0 at mainbus0 addr 0xff000000: Google Goldfish PIC
[ 1.0000000] gfpic0: interrupting at IPL 1
[ 1.0000000] gfpic1 at mainbus0 addr 0xff001000: Google Goldfish PIC
[ 1.0000000] gfpic1: interrupting at IPL 2
[ 1.0000000] gfpic2 at mainbus0 addr 0xff002000: Google Goldfish PIC
[ 1.0000000] gfpic2: interrupting at IPL 3
[ 1.0000000] gfpic3 at mainbus0 addr 0xff003000: Google Goldfish PIC
[ 1.0000000] gfpic3: interrupting at IPL 4
[ 1.0000000] gfpic4 at mainbus0 addr 0xff004000: Google Goldfish PIC
[ 1.0000000] gfpic4: interrupting at IPL 5
[ 1.0000000] gfpic5 at mainbus0 addr 0xff005000: Google Goldfish PIC
[ 1.0000000] gfpic5: interrupting at IPL 6
[ 1.0000000] gfrtc0 at mainbus0 addr 0xff006000: Google Goldfish RTC + timer
[ 1.0000000] gfrtc0: hardclock interrupting at gfpic5 irq 1 (IPL 6)
[ 1.0000000] gfrtc0: Using as delay() timer.
[ 1.0000000] gfrtc1 at mainbus0 addr 0xff007000: Google Goldfish RTC + timer
[ 1.0000000] gfrtc1: using as Time of Day Register.
[ 1.0000000] gftty0 at mainbus0 addr 0xff008000: Google Goldfish TTY
[ 1.0000000] gftty0: console
[ 1.0000000] gftty0: interrupting at gfpic0 irq 32 (IPL 1)
[ 1.0000000] virtctrl0 at mainbus0 addr 0xff009000: Qemu Virtual System Controller
[ 1.0000000] virtctrl0: features=0x00000001
[ 1.0000000] virtio0 at mainbus0 addr 0xff01fc00
[ 1.0000000] virtio0: VirtIO-MMIO-v2
[ 1.0000000] virtio0: network device (id 1, rev. 0x01)
[ 1.0000000] vioif0 at virtio0: features: 0x100000020<V1,MAC>
[ 1.0000000] vioif0: Ethernet address 52:54:00:12:34:56
[ 1.0000000] virtio0: interrupting at gfpic4 irq 31 (IPL 5)
[ 1.0000000] virtio1 at mainbus0 addr 0xff01fe00
[ 1.0000000] virtio1: VirtIO-MMIO-v2
[ 1.0000000] virtio1: block device (id 2, rev. 0x01)
[ 1.0000000] ld0 at virtio1: features: 0x100000244<V1,FLUSH,BLK_SIZE,SEG_MAX>
[ 1.0000000] ld0: max 62 segs of max 65536 bytes
[ 1.0000000] virtio1: interrupting at gfpic4 irq 32 (IPL 5)
[ 1.0000000] ld0: 1024 KB, 2 cyl, 16 head, 63 sec, 512 bytes/sect x 2048 sectors (0 bytes/physsect)
[ 1.0000000] Spurious interrupt on CPU ipl 5
[ 1.0000000] WARNING: system needs entropy for security; see entropy(7)
[ 1.0000000] No statclock; using hardclock.
[ 1.0000000] Initialzing hardclock: freq=100 Hz, interval=10000 usec
[ 2.5500030] swwdog0: software watchdog initialized
[ 2.5800030] Initializing root RAM disk @ 0xef00000 - 0xeffffff
[ 2.6000030] root on md0a dumps on md0b
[ 2.6300030] root file system type: ffs
[ 2.6300030] kern.module.path=/stand/virt68k/11.0/modules
[ 2.6500030] WARNING: preposterous TOD clock time
[ 2.6500030] WARNING: using filesystem time
[ 2.6600030] WARNING: CHECK AND RESET THE DATE!
[ 7.0000030] entropy: best effort途中Qemuとか出てくるのはNetBSD/virt68kの仕様。6.0.1なのは、QEMU 6.0.1に合わせただけで意味はない。
続く（かな？）