init

.cargo/config.toml

@@ -0,0 +1,8 @@
+[build]
+target = "riscv64gc-unknown-none-elf"
+
+[target.riscv64gc-unknown-none-elf]
+rustflags = "-C target-feature=-c" # Disable compressed instructions
+
+[unstable]
+build-std = ["core", "alloc", "compiler_builtins"]

.gitignore

@@ -0,0 +1,2 @@
+/target
+log.txt

.vscode/settings.json

@@ -0,0 +1,6 @@
+{
+    "rust-analyzer.cargo.target": "riscv64gc-unknown-none-elf",
+    "rust-analyzer.check.allTargets": false,
+    "rust-analyzer.imports.preferNoStd": true,
+    "rust-analyzer.showUnlinkedFileNotification": false,
+}

Cargo.toml

@@ -0,0 +1,32 @@
+[workspace]
+members = ["allocator", "hal-core", "hal-riscv"]
+exclude = ["runner", "usercode"]
+resolver = "2"
+
+[package]
+name = "pathos"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[lib]
+harness = false
+test = false
+
+[[bin]]
+name = "pathos"
+harness = false
+
+[dependencies]
+hal-riscv = { path = "hal-riscv" }
+hal-core = { path = "hal-core" }
+allocator = { path = "allocator" }
+owo-colors = "4.0.0"
+spin = "0.9.8"
+once_cell = { version = "1.19.0", features = [
+    "alloc",
+    "race",
+], default-features = false }
+elf = { version = "0.7.4", default-features = false }
+uart_16550 = "0.3.0"

README.md

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+## PathOS kernel code
+
+This is the kernel code for the PathOS operating system. It is a simple kernel that runs on the RISC-V architecture.
+
+## Development
+
+Install riscv64 toolchain to ~/.local/bin
+https://mirrors.edge.kernel.org/pub/tools/crosstool/files/bin/x86_64/13.2.0/x86_64-gcc-13.2.0-nolibc-riscv64-linux.tar.gz
+
+Install `qemu-system` and `qemu-system-riscv64`.
+
+zzz

allocator/Cargo.toml

@@ -0,0 +1,4 @@
+[package]
+name = "allocator"
+version = "0.1.0"
+edition = "2021"

allocator/README.md

@@ -0,0 +1,18 @@
+```
+// Smallest block = 8 bytes
+// Allocatable memory size = 64 bytes
+// Highest order = 3 (2^3 * 8 = 64)
+// Calculate order from smallest block and allocatable memory size:
+// 2 ^ n = memsize / blocksize
+// n = log2(memsize / blocksize)
+
+// 3               64
+// 2        32             32
+// 1   16      16      16     16
+// 0 8   8   8   8   8   8   8   8
+
+// Number of nodes = 2 ^ (order + 1) - 1
+// Total size required to bookkeep allocatable memory = num_nodes * node_size
+// For order = 3 and node_size = 8, total size = (2 ^ (3 + 1) - 1) * 8 = 15 * 8
+// = 120
+```

allocator/justfile

@@ -0,0 +1,5 @@
+test:
+    cargo test --lib --target x86_64-unknown-linux-gnu --jobs 1
+
+
+