Ryan Houdek
e95c8d703c
In order to support `vmaskmov{ps,pd}` without SVE128 this is required.
It's pretty gnarly but they aren't often used so that's fine from a
compatibility perspective.
Example SVE128 implementation:
```json
"vmaskmovps ymm0, ymm1, [rax]": {
"ExpectedInstructionCount": 9,
"Comment": [
"Map 2 0b01 0x2c 256-bit"
],
"ExpectedArm64ASM": [
"ldr q2, [x28, #32]",
"mrs x20, nzcv",
"cmplt p0.s, p6/z, z17.s, #0",
"ld1w {z16.s}, p0/z, [x4]",
"add x21, x4, #0x10 (16)",
"cmplt p0.s, p6/z, z2.s, #0",
"ld1w {z2.s}, p0/z, [x21]",
"str q2, [x28, #16]",
"msr nzcv, x20"
]
},
```
Example ASIMD implementation
```json
"vmaskmovps ymm0, ymm1, [rax]": {
"ExpectedInstructionCount": 37,
"Comment": [
"Map 2 0b01 0x2c 256-bit"
],
"ExpectedArm64ASM": [
"ldr q2, [x28, #32]",
"mrs x20, nzcv",
"movi v0.2d, #0x0",
"mov x1, x4",
"mov x0, v17.d[0]",
"tbz x0, #63, #+0x8",
"ld1 {v0.s}[0], [x1]",
"add x1, x1, #0x4 (4)",
"tbz w0, #31, #+0x8",
"ld1 {v0.s}[1], [x1]",
"add x1, x1, #0x4 (4)",
"mov x0, v17.d[1]",
"tbz x0, #63, #+0x8",
"ld1 {v0.s}[2], [x1]",
"add x1, x1, #0x4 (4)",
"tbz w0, #31, #+0x8",
"ld1 {v0.s}[3], [x1]",
"mov v16.16b, v0.16b",
"add x21, x4, #0x10 (16)",
"movi v0.2d, #0x0",
"mov x1, x21",
"mov x0, v2.d[0]",
"tbz x0, #63, #+0x8",
"ld1 {v0.s}[0], [x1]",
"add x1, x1, #0x4 (4)",
"tbz w0, #31, #+0x8",
"ld1 {v0.s}[1], [x1]",
"add x1, x1, #0x4 (4)",
"mov x0, v2.d[1]",
"tbz x0, #63, #+0x8",
"ld1 {v0.s}[2], [x1]",
"add x1, x1, #0x4 (4)",
"tbz w0, #31, #+0x8",
"ld1 {v0.s}[3], [x1]",
"mov v2.16b, v0.16b",
"str q2, [x28, #16]",
"msr nzcv, x20"
]
},
```
There's a little bit of an improvement where nzcv isn't needed to get
touched on the ASIMD implementation, but I'll leave that for a future
improvement.
FEX - Fast x86 emulation frontend
FEX allows you to run x86 and x86-64 binaries on an AArch64 host, similar to qemu-user and box86. It has native support for a rootfs overlay, so you don't need to chroot, as well as some thunklibs so it can forward things like GL to the host. FEX presents a Linux 5.0+ interface to the guest, and supports only AArch64 as a host. FEX is very much work in progress, so expect things to change.
Quick start guide
For Ubuntu 20.04, 21.04, 21.10, 22.04
Execute the following command in the terminal to install FEX through a PPA.
curl --silent https://raw.githubusercontent.com/FEX-Emu/FEX/main/Scripts/InstallFEX.py --output /tmp/InstallFEX.py && python3 /tmp/InstallFEX.py && rm /tmp/InstallFEX.py
This command will walk you through installing FEX through a PPA, and downloading a RootFS for use with FEX.
Ubuntu PPA is updated with our monthly releases.
For everyone else
Please see Building FEX.
Getting Started
FEX has been tested to build and run on ARMv8.0+ hardware. ARMv7 hardware will not work. Expected operating system usage is Linux. FEX has been tested with Ubuntu 20.04, 20.10, and 21.04. Also Arch Linux.
On AArch64 hosts the user MUST have an x86-64 RootFS Creating a RootFS.
Navigating the Source
See the Source Outline for more information.
Building FEX
Follow the guide on the official FEX-Emu Wiki here.
RootFS generation
AArch64 hosts require a rootfs for running applications. Follow the guide on the wiki page for seeing how to set up the rootfs from scratch https://wiki.fex-emu.com/index.php/Development:Setting_up_RootFS
