fuel: add the SGI Fuel (IP34 board, IP35 platform)

CHANGELOG.md

@@ -327,6 +327,31 @@ hashes are given where a change is easiest to understand by reading the commit.
 - Memory past 4 GB is as fast as the rest: such a machine gets a 16 GB direct
   window, and the JIT compiles code anywhere in it.
 - A store-conditional on memory outside the window is now atomic with two CPUs.
+### SGI Fuel (IP34 board, IP35 software platform)
+
+- **The Fuel takes a VPro board**: `[graphics] board = "v12"` or `"v10"`
+  fits the Octane's VPro model at crossbar widget 13. IRIX 6.5.30 with the
+  VPro driver brings the X login screen up on it.
+
+- Added a headless Fuel profile with the 500 MHz R14000, 512 MiB RAM,
+  Bedrock, dual-head XBridge, IOC3 networking and two-channel ISP12160 SCSI.
+  The normal interpreter boot reaches the IRIX 6.5.30 root shell with PROM
+  6.210. See the [Fuel guide](docs/fuel-ip34.md).
+- **jitv2 compiles the reset PROM from the PROM.** The PROM runs from the reset
+  window uncached; once memory covers that window the cached view returns RAM
+  there, and the compile pool used to compile RAM's bytes in place of the
+  PROM's. The board now presents an uncached instruction fetch of that window at
+  an address of the PROM's own (`MipsExecutor::uncached_fetch_alias`), so its
+  code page is keyed, compiled and invalidated by address like any other. The
+  other machines are unchanged.
+
+### PCI configuration
+
+- A PCI function can describe its own writable header fields and
+  write-one-to-clear status bits. Byte and halfword configuration writes
+  through a Bridge carry their byte enables, so such a function keeps the
+  status events a narrow write did not select. No Octane function has
+  write-one-to-clear status bits, so the Octane behaves as before.
 
 ### VNC, and screen and pointer commands
 

FEATURES.md

@@ -175,15 +175,34 @@ the first `[section]`, because TOML tables continue until the next header.
 
 | Key | Default | Values and behavior |
 |---|---|---|
-| `machine.profile` | `indy_ip24` | indy_ip24, indigo2_ip22, indigo2_ip28, o2_ip32 (configured by `[o2]`, see [the O2 guide](docs/o2-ip32.md)), octane_ip30 (configured by `[octane]`, see [the Octane guide](docs/octane-ip30.md)). |
-| `machine.cpu` | the machine's first | A family (`r4400`, `r5000`, `r10000`, `r12000`, `r14000`) or a part (`r14000_600`); independent of build features. Indy and `indigo2_ip22`: r4400, r5000; `indigo2_ip28`: r10000; O2: r5000, r10000, r12000; Octane: r10000, r12000, r14000. The first listed is the default. |
+| `machine.profile` | `indy_ip24` | indy_ip24, indigo2_ip22, indigo2_ip28, o2_ip32 (configured by `[o2]`, see [the O2 guide](docs/o2-ip32.md)), octane_ip30 (configured by `[octane]`, see [the Octane guide](docs/octane-ip30.md)), fuel_ip34 (see [the Fuel guide](docs/fuel-ip34.md)). |
+| `machine.cpu` | the machine's first | A family (`r4400`, `r5000`, `r10000`, `r12000`, `r14000`) or a part (`r14000_600`); independent of build features. Indy and `indigo2_ip22`: r4400, r5000; `indigo2_ip28`: r10000; O2: r5000, r10000, r12000; Octane: r10000, r12000, r14000; Fuel: r14000 (`r14000_500`). The first listed is the default. |
 | `machine.cpus` | `1` | Processors fitted. 2 only on the Octane; see [its guide](docs/Octane/multiprocessor.md). |
 
+### [fuel]
+
+Fuel-specific settings apply when `machine.profile = "fuel_ip34"`.
+
+| Key | Default | Values and behavior |
+|---|---|---|
+| `flash` | unset | Persistent 16 MiB boot-flash file. Unset, the flash is volatile. |
+| `console` | `l1` | `l1`, `ioc3a` or `ioc3b`. Selects the guest console connection. |
+| `l1_port` | `8882` | Host TCP port for the L1 console. Used when `console = "l1"`. |
+| `l1_log` | unset | Optional serial log path for L1 output when an IOC3 port is selected as console. |
+| `l1_revision` | `1.48.1` | L1 firmware revision as `major.minor.patch`, decimal. The guest reads it with L1 request `0x0005`. |
+| `brick_serial` | `EMUN00` | L1 brick serial, at most 37 bytes. The guest reads it with L1 request `0x0004`. The default is a marked synthetic serial, not a real one. |
+
+The machine uses one 500 MHz R14000 and fixed 512 MiB RAM in two 256 MiB
+banks. Its IOC3 has no keyboard or mouse ports, so it runs on a serial
+console. A `[fuel]` table is written to a saved config only when one of
+these keys is set. The sample configuration and supported PROM inputs are in the
+[Fuel guide](docs/fuel-ip34.md).
+
 ### [graphics]
 
 | Key | Default | Values and behavior |
 |---|---|---|
-| `graphics.board` | `newport`; `solidimpact` on the Octane | newport, xz, extreme, solidimpact, highimpact, maximpact, v6, v8, v10, v12, none. Extreme is Indigo2 only. The Octane takes only `solidimpact` (SI), `highimpact` (SI with texture option), `maximpact` (MXI), `v6`, `v8`, `v10`, `v12` (the VPro boards, also `vpro:v12` and so on; need an IRIX install with the VPro driver, IRIX 6.5.10 or later and PROM 4.0, or 4.5 for the V10 and V12, which shipped only in the Octane2 and so give the machine the Octane2's Crossbow 1.4 and Bridge revision) or `none` (no board: the machine runs on its serial console, with no window). |
+| `graphics.board` | `newport`; `solidimpact` on the Octane | newport, xz, extreme, solidimpact, highimpact, maximpact, v6, v8, v10, v12, none. Extreme is Indigo2 only. The Octane takes only `solidimpact` (SI), `highimpact` (SI with texture option), `maximpact` (MXI), `v6`, `v8`, `v10`, `v12` (the VPro boards, also `vpro:v12` and so on; need an IRIX install with the VPro driver, IRIX 6.5.10 or later and PROM 4.0, or 4.5 for the V10 and V12, which shipped only in the Octane2 and so give the machine the Octane2's Crossbow 1.4 and Bridge revision) or `none` (no board: the machine runs on its serial console, with no window). The Fuel takes `v12` or `v10` in its graphics slot, or `none`, its default. |
 | `graphics.heads` | `1` | 1 or 2; dual-head requires Newport. |
 | `graphics.resolution` | `guest` | guest, 1024x768, 1280x960, 1280x1024; presets require Newport. |
 | `graphics.threads` | `2` | Worker threads the board's fragment pipeline draws on, at least 1. VPro: the screen tiles' owners, besides its front-end and raster threads; more help on a host with cores to spare. |
@@ -218,7 +237,7 @@ An explicit non-disk kind takes precedence over the legacy cdrom flag.
 
 | Key | Default | Values and behavior |
 |---|---|---|
-| `network.mode` | `nat` | nat, pcap, stream or off (no Ethernet; O2 and Octane only). Stream needs `network.stream`. PCAP needs build support and host capture permissions. PCAP works on every Ethernet; stream on every onboard one, not on a DaynaPort. |
+| `network.mode` | `nat` | nat, pcap, stream or off (no Ethernet; O2, Octane and Fuel only). Stream needs `network.stream`. PCAP needs build support and host capture permissions. PCAP works on every Ethernet; stream on every onboard one, not on a DaynaPort. |
 | `network.stream` | `unset` | `tcp:IP:PORT` or `unix:PATH`: the server of the private segment for `mode = "stream"` (QEMU `-netdev stream` framing). See NETWORKING.md. |
 | `network.pcap_interface` | `auto-pick when unset` | Interface name or numeric list index; PCAP only. |
 | `network.nfs_pcap_ip` | `unset` | Virtual LAN IP for the built-in NFS responder in PCAP mode. |
@@ -382,8 +401,8 @@ IP22/IP24 four-bank IRIX 6.5 behavior remains separate from IP28's verified
 two-bank 1 GB layout. Extreme requires IP22. All non-Newport boards require
 `heads=1` and `resolution="guest"`. IP28 IRIX needs IMPACT; its PROM has an
 embedded fallback.
-The config validator permits SCSI controller 1 only on IP22, the O2 and the
-Octane, the machines with two controllers.
+The config validator permits SCSI controller 1 only on IP22, the O2, Octane
+and Fuel. These machines have two controllers.
 
 Standalone CLI options update the loaded config where supplied; boolean enable
 switches do not provide a general way to clear every saved true setting.
@@ -436,7 +455,7 @@ iris-gui does not parse this standalone option set; use its named-machine UI.
 | `--list-net-interfaces` | Print the host network interfaces libpcap can bridge onto, then exit. Requires a build with --features pcap. |
 | `--no-scsi-deferred-int` | Disable deferred SCSI status interrupts (default: enabled for OpenBSD/NetBSD compatibility). |
 | `--cpu` | Emulated CPU: a family (`r4400`, `r5000`, `r10000`, `r12000`, `r14000`) or a part (`r14000_600`) the machine takes. Overrides `[machine] cpu`.  |
-| `--graphics` | Graphics board: `newport` (default), `xz`, `extreme`, `solidimpact`, `highimpact`, `maximpact` (or `impact:solid`, `impact:high`, `impact:max`), `v6`, `v8`, `v10`, `v12` (`vpro:v12` and so on, Octane only). |
+| `--graphics` | Graphics board: `newport` (default), `xz`, `extreme`, `solidimpact`, `highimpact`, `maximpact` (or `impact:solid`, `impact:high`, `impact:max`), `v6`, `v8`, `v10`, `v12` (`vpro:v12` and so on; Octane, and `v10`/`v12` on the Fuel). |
 | `--raster` | VPro: `cpu` (default) or `wgpu`, the raster unit on the host GPU (`[graphics] raster`; needs a build with the `wgpu` feature). |
 | `--renderer` | What draws the window: `gl` (default) or `wgpu` (`renderer`; needs a build with the `wgpu` feature). |
 | `--gdb-port` | Enable GDB stub on the given TCP port (e.g. --gdb-port 1234). Connect with: target remote localhost:<port> |