Display server and graphical console

Cargo.toml

@@ -1,7 +1,11 @@
 [workspace]
 resolver = "2"
 members = [
+    "crates/console",
     "crates/device-tree",
+    "crates/display-client",
+    "crates/display-proto",
+    "crates/display-server",
     "crates/elf",
     "crates/endian",
     "crates/filesystem",

crates/console/.gitignore

@@ -0,0 +1 @@
+*.elf

crates/console/Cargo.toml

@@ -0,0 +1,15 @@
+[package]
+name = "console"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+bytemuck = "1.21.0"
+unicode-segmentation = "1.12"
+
+display-client = { path = "../display-client" }
+lz4 = { path = "../lz4" }
+ulib = { path = "../ulib", features = ["heap-impl"] }
+
+[dev-dependencies]
+ulib = { path = "../ulib", features = ["test"] }

crates/console/build.rs

@@ -0,0 +1,6 @@
+fn main() {
+    let crate_root = std::env::var("CARGO_MANIFEST_DIR").unwrap();
+    println!("cargo::rerun-if-changed=../ulib/script.ld");
+    println!("cargo::rustc-link-arg-bins=-T{crate_root}/../ulib/script.ld");
+    println!("cargo::rustc-link-arg-bins=-n");
+}

crates/console/build.sh

@@ -0,0 +1,19 @@
+#!/usr/bin/env bash
+
+set -ex
+
+BIN="console"
+TARGET=aarch64-unknown-none-softfloat
+PROFILE=${PROFILE-"release"}
+
+cargo rustc --profile="${PROFILE}" \
+    --target=${TARGET} -- \
+    -C relocation-model=static
+
+if test "$PROFILE" = "dev" ; then
+    BINARY=../../target/${TARGET}/debug/${BIN}
+else
+    BINARY=../../target/${TARGET}/${PROFILE}/${BIN}
+fi
+
+cp "${BINARY}" "${BIN}".elf

crates/console/src/color.rs

@@ -0,0 +1,23 @@
+pub const fn rgba(r: u8, g: u8, b: u8, a: u8) -> u32 {
+    u32::from_be_bytes([a, r, g, b])
+}
+
+pub const fn de_rgba(color: u32) -> (u8, u8, u8, u8) {
+    let [a, r, g, b] = color.to_be_bytes();
+    (r, g, b, a)
+}
+
+pub fn blend(one: u32, two: u32) -> u32 {
+    let [a, r, g, b] = one.to_be_bytes().map(u32::from);
+    if a == 255 {
+        return one;
+    }
+    let [_bg_a, bg_r, bg_g, bg_b] = two.to_be_bytes().map(u32::from);
+    // TODO: blend in linear space?
+    let (r, g, b) = (
+        (r * a + bg_r * (255 - a)) / 255,
+        (g * a + bg_g * (255 - a)) / 255,
+        (b * a + bg_b * (255 - a)) / 255,
+    );
+    u32::from_be_bytes([a, r, g, b].map(|b| b as u8))
+}