From 2f9f5f0de17119f91dcea59fc9d0ecee7befd582 Mon Sep 17 00:00:00 2001
From: Jonathan DeMarks <jmdemarks@spscommerce.com>
Date: Thu, 21 Sep 2023 11:45:49 -0500
Subject: [PATCH 1/9] Rust edition - x86_64

---
 .cargo/config.toml           |  6 ++++
 .gitignore                   |  1 +
 Cargo.lock                   |  7 ++++
 Cargo.toml                   | 10 ++++++
 rs-nap/Cargo.lock            |  7 ++++
 rs-nap/Cargo.toml            |  8 +++++
 rs-nap/src/main.rs           | 61 +++++++++++++++++++++++++++++++++
 rs-nap/src/support.rs        |  7 ++++
 rs-nap/src/support/noarch.rs | 65 ++++++++++++++++++++++++++++++++++++
 rs-nap/src/support/x86_64.rs | 40 ++++++++++++++++++++++
 rust-toolchain.toml          |  4 +++
 11 files changed, 216 insertions(+)
 create mode 100644 .cargo/config.toml
 create mode 100644 Cargo.lock
 create mode 100644 Cargo.toml
 create mode 100644 rs-nap/Cargo.lock
 create mode 100644 rs-nap/Cargo.toml
 create mode 100644 rs-nap/src/main.rs
 create mode 100644 rs-nap/src/support.rs
 create mode 100644 rs-nap/src/support/noarch.rs
 create mode 100644 rs-nap/src/support/x86_64.rs
 create mode 100644 rust-toolchain.toml

diff --git a/.cargo/config.toml b/.cargo/config.toml
new file mode 100644
index 0000000..819fac3
--- /dev/null
+++ b/.cargo/config.toml
@@ -0,0 +1,6 @@
+[build]
+rustflags = [
+    "-Clink-args=-nostartfiles",
+    "-Clink-args=-Wl,-n,-N,--no-dynamic-linker,--build-id=none",
+    "-Crelocation-model=static"
+]
\ No newline at end of file
diff --git a/.gitignore b/.gitignore
index 553042b..c771476 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,3 @@
 .idea
 out/
+target/
diff --git a/Cargo.lock b/Cargo.lock
new file mode 100644
index 0000000..6ddf31f
--- /dev/null
+++ b/Cargo.lock
@@ -0,0 +1,7 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "rs-nap"
+version = "0.1.0"
diff --git a/Cargo.toml b/Cargo.toml
new file mode 100644
index 0000000..cfdc123
--- /dev/null
+++ b/Cargo.toml
@@ -0,0 +1,10 @@
+[workspace]
+resolver = "2"
+members = ["rs-nap"]
+
+[profile.release]
+strip = true
+opt-level = "z"
+codegen-units = 1
+panic = "abort"
+lto = true
diff --git a/rs-nap/Cargo.lock b/rs-nap/Cargo.lock
new file mode 100644
index 0000000..6ddf31f
--- /dev/null
+++ b/rs-nap/Cargo.lock
@@ -0,0 +1,7 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "rs-nap"
+version = "0.1.0"
diff --git a/rs-nap/Cargo.toml b/rs-nap/Cargo.toml
new file mode 100644
index 0000000..dab6002
--- /dev/null
+++ b/rs-nap/Cargo.toml
@@ -0,0 +1,8 @@
+[package]
+name = "rs-nap"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
diff --git a/rs-nap/src/main.rs b/rs-nap/src/main.rs
new file mode 100644
index 0000000..a067d57
--- /dev/null
+++ b/rs-nap/src/main.rs
@@ -0,0 +1,61 @@
+#![no_std]
+#![no_main]
+#![feature(naked_functions)]
+
+mod support;
+use support::*;
+use core::arch::asm;
+use core::slice::from_raw_parts as mkslice;
+
+#[no_mangle]
+pub unsafe fn nap(args: &[*const u8]) {
+    let mut sleep_time:usize = 10;
+
+    if args.len() < 2 {
+        sleep(sleep_time, false);
+    } else {
+        let (seconds,_) = from_radix_10(mkslice(args[1], strlen(args[1])));
+        let mut good_input = seconds > 0 && seconds < 1000000000;
+
+        if good_input {
+            sleep_time = seconds;
+        } else {
+            good_input = false;
+        }
+
+        sleep(sleep_time, good_input);
+    }
+
+    print_str(b"Done!\n");
+    sys_exit(0);
+}
+
+pub unsafe fn sleep(seconds: usize, good_input: bool) {
+    if good_input == false {
+        print_str(b"Bad input. ");
+    }
+    print_str(b"Sleeping for ");
+    print_num(seconds);
+    print_str(b" seconds...\n");
+    sys_sleep(seconds)
+}
+
+#[no_mangle]
+#[naked]
+pub unsafe extern "C" fn _start() {
+    #[cfg(all(target_arch="x86_64", target_os="linux"))]
+    asm!("mov rdi, rsp", "call get_args", options(noreturn))
+}
+
+#[no_mangle]
+pub unsafe fn get_args(stack_top: *const u8) {
+    let argc = *(stack_top as *const u64);
+    let argv = stack_top.add(8) as *const *const u8;
+    let args = mkslice(argv, argc as usize);
+    nap(args)
+}
+
+#[panic_handler]
+unsafe fn my_panic(_info: &core::panic::PanicInfo) -> ! {
+    sys_exit(255)
+}
diff --git a/rs-nap/src/support.rs b/rs-nap/src/support.rs
new file mode 100644
index 0000000..b19e8c2
--- /dev/null
+++ b/rs-nap/src/support.rs
@@ -0,0 +1,7 @@
+#[cfg_attr(all(target_arch="x86_64", target_os="linux"), path="support/x86_64.rs")]
+mod support;
+pub use support::*;
+
+#[path="support/noarch.rs"]
+mod noarch;
+pub use noarch::*;
diff --git a/rs-nap/src/support/noarch.rs b/rs-nap/src/support/noarch.rs
new file mode 100644
index 0000000..8f33330
--- /dev/null
+++ b/rs-nap/src/support/noarch.rs
@@ -0,0 +1,65 @@
+use crate::support::sys_write;
+
+pub unsafe fn strlen(mut s: *const u8) -> usize {
+  let mut count = 0;
+  while *s != b'\0' {
+      count += 1;
+      s = s.add(1);
+  }
+  count
+}
+
+pub fn print_str(s: &[u8]) {
+  unsafe {
+      sys_write(s.as_ptr(), s.len());
+  }
+}
+
+pub fn print_num(n: usize) {
+  if n > 9 {
+      print_num(n / 10);
+  }
+  let c = b'0' + (n % 10) as u8;
+  print_str(&[c]);
+}
+
+fn nth(n: u8) -> usize
+{
+    let mut i:usize = 0;
+    for _ in 0..n {
+        i = i + 1;
+    }
+    i
+}
+
+pub fn ascii_to_digit(character: u8) -> Option<usize> {
+    match character {
+        b'0' => Some(nth(0)),
+        b'1' => Some(nth(1)),
+        b'2' => Some(nth(2)),
+        b'3' => Some(nth(3)),
+        b'4' => Some(nth(4)),
+        b'5' => Some(nth(5)),
+        b'6' => Some(nth(6)),
+        b'7' => Some(nth(7)),
+        b'8' => Some(nth(8)),
+        b'9' => Some(nth(9)),
+        _ => None,
+    }
+}
+
+pub fn from_radix_10(text: &[u8]) -> (usize, usize) {
+  let mut index:usize = 0;
+  let mut number:usize = 0;
+  while index != text.len() {
+      if let Some(digit) = ascii_to_digit(text[index]) {
+          number *= nth(10);
+          number += digit;
+          index += 1;
+      } else {
+          break;
+      }
+  }
+  (number, index)
+}
+
diff --git a/rs-nap/src/support/x86_64.rs b/rs-nap/src/support/x86_64.rs
new file mode 100644
index 0000000..c77d87d
--- /dev/null
+++ b/rs-nap/src/support/x86_64.rs
@@ -0,0 +1,40 @@
+use core::arch::asm;
+
+pub unsafe fn sys_exit(exit_code:usize) -> ! {
+    asm!("syscall",
+            in("rax") 60,
+            in("rdi") exit_code,
+            options(nostack, noreturn)
+    )
+}
+
+pub unsafe fn sys_write(buffer: *const u8, count: usize) {
+    asm!("syscall",
+            inout("rax") 1 => _,
+            in("rdi") 1,
+            in("rsi") buffer,
+            in("rdx") count,
+            lateout("rcx") _,
+            lateout("r11") _,
+            options(nostack)
+    )
+}
+
+#[repr(C)]
+struct timespec {
+    pub tv_sec:  isize,
+    pub tv_nsec: isize,
+}
+
+pub unsafe fn sys_sleep(seconds: usize) {
+    let sleep_time = timespec {
+        tv_sec:  seconds as isize,
+        tv_nsec: 0
+    };
+
+    asm!("syscall",
+            in("rax") 35,
+            in("rdi") &sleep_time,
+            in("rsi") 0,
+            options(nostack))
+}
diff --git a/rust-toolchain.toml b/rust-toolchain.toml
new file mode 100644
index 0000000..1ea7d64
--- /dev/null
+++ b/rust-toolchain.toml
@@ -0,0 +1,4 @@
+[toolchain]
+channel = "nightly"
+components = [ "rustfmt", "clippy" ]
+targets = [ "x86_64-unknown-linux-gnu" ]

From 89b6d9fda4662262d8a07352a421b51ef7875038 Mon Sep 17 00:00:00 2001
From: Jonathan DeMarks <jmdemarks@spscommerce.com>
Date: Thu, 21 Sep 2023 16:47:28 -0500
Subject: [PATCH 2/9] aarch64 support - todo: fix write syscall

---
 .cargo/config.toml            | 13 ++++++++--
 rs-nap/README.md              | 44 ++++++++++++++++++++++++++++++++
 rs-nap/src/main.rs            | 14 +++--------
 rs-nap/src/support.rs         |  1 +
 rs-nap/src/support/aarch64.rs | 47 +++++++++++++++++++++++++++++++++++
 rs-nap/src/support/interop.rs |  5 ++++
 rs-nap/src/support/x86_64.rs  | 19 +++++++++-----
 rust-toolchain.toml           |  5 +++-
 8 files changed, 128 insertions(+), 20 deletions(-)
 create mode 100644 rs-nap/README.md
 create mode 100644 rs-nap/src/support/aarch64.rs
 create mode 100644 rs-nap/src/support/interop.rs

diff --git a/.cargo/config.toml b/.cargo/config.toml
index 819fac3..abf44e2 100644
--- a/.cargo/config.toml
+++ b/.cargo/config.toml
@@ -1,6 +1,15 @@
-[build]
+[target.x86_64-unknown-linux-gnu]
+linker = "x86_64-linux-gnu-gcc"
 rustflags = [
     "-Clink-args=-nostartfiles",
     "-Clink-args=-Wl,-n,-N,--no-dynamic-linker,--build-id=none",
     "-Crelocation-model=static"
-]
\ No newline at end of file
+]
+
+[target.aarch64-unknown-linux-gnu]
+linker = "aarch64-linux-gnu-gcc"
+rustflags = [
+    "-Clink-args=-nostartfiles",
+    "-Clink-args=-Wl,-n,-N,--no-dynamic-linker,--build-id=none",
+    "-Crelocation-model=static"
+]
diff --git a/rs-nap/README.md b/rs-nap/README.md
new file mode 100644
index 0000000..9d0886c
--- /dev/null
+++ b/rs-nap/README.md
@@ -0,0 +1,44 @@
+# Rust rewrite
+
+## Goals
+
+### Feature parity
+
+- [x] Maintain roughly the same binary size
+- [x] Zero requirements other than the linux kernel
+- [x] Increased readability over assembly
+- [x] Shared code base for all architectures
+
+### Architecture support
+
+- [x] x86_64 implementation
+- [x] aarch64 implementation
+
+## Run on a native processor
+
+```sh
+# Build
+cargo build --release
+# Display file size
+ls -lah ./target/release/rs-nap
+# Run for 3 seconds
+./target/release/rs-nap 3
+```
+
+## Run on an emulated processor
+
+```sh
+# Install cross compiler and emulation layer
+
+# Debian-based distros
+sudo apt -y install gcc-aarch64-linux-gnu binutils-aarch64-linux-gnu qemu-user-static
+```
+
+```sh
+# Build
+cargo build --target aarch64-unknown-linux-gnu --release
+# Display file size
+ls -lah target/aarch64-unknown-linux-gnu/release/rs-nap
+# Run for 3 seconds
+qemu-aarch64-static target/aarch64-unknown-linux-gnu/release/rs-nap 3
+```
diff --git a/rs-nap/src/main.rs b/rs-nap/src/main.rs
index a067d57..08a34a8 100644
--- a/rs-nap/src/main.rs
+++ b/rs-nap/src/main.rs
@@ -4,11 +4,10 @@
 
 mod support;
 use support::*;
-use core::arch::asm;
 use core::slice::from_raw_parts as mkslice;
 
 #[no_mangle]
-pub unsafe fn nap(args: &[*const u8]) {
+pub unsafe fn nap(args: &[*const u8]) -> ! {
     let mut sleep_time:usize = 10;
 
     if args.len() < 2 {
@@ -41,15 +40,8 @@ pub unsafe fn sleep(seconds: usize, good_input: bool) {
 }
 
 #[no_mangle]
-#[naked]
-pub unsafe extern "C" fn _start() {
-    #[cfg(all(target_arch="x86_64", target_os="linux"))]
-    asm!("mov rdi, rsp", "call get_args", options(noreturn))
-}
-
-#[no_mangle]
-pub unsafe fn get_args(stack_top: *const u8) {
-    let argc = *(stack_top as *const u64);
+unsafe fn get_args(stack_top: *const u8) {
+    let argc = *(stack_top as *const usize);
     let argv = stack_top.add(8) as *const *const u8;
     let args = mkslice(argv, argc as usize);
     nap(args)
diff --git a/rs-nap/src/support.rs b/rs-nap/src/support.rs
index b19e8c2..47e42b6 100644
--- a/rs-nap/src/support.rs
+++ b/rs-nap/src/support.rs
@@ -1,4 +1,5 @@
 #[cfg_attr(all(target_arch="x86_64", target_os="linux"), path="support/x86_64.rs")]
+#[cfg_attr(all(target_arch="aarch64", target_os="linux"), path="support/aarch64.rs")]
 mod support;
 pub use support::*;
 
diff --git a/rs-nap/src/support/aarch64.rs b/rs-nap/src/support/aarch64.rs
new file mode 100644
index 0000000..1a3d2d9
--- /dev/null
+++ b/rs-nap/src/support/aarch64.rs
@@ -0,0 +1,47 @@
+use core::arch::asm;
+use core::slice::from_raw_parts as mkslice;
+
+mod interop;
+use interop::timespec;
+
+#[no_mangle]
+#[naked]
+unsafe extern "C" fn _start() {
+    // Move the stack pointer before it gets clobbered
+    asm!("mov fp, sp",
+         "mov x0, fp",
+         "bl get_args",
+         options(noreturn))
+}
+
+pub unsafe fn sys_exit(exit_code:usize) -> ! {
+    asm!("svc 0",
+         in("x8") 93,
+         in("x0") exit_code,
+         options(nostack, noreturn)
+    )
+}
+
+pub unsafe fn sys_write(buffer: *const u8, count: usize) {
+    asm!("svc 0", "ret",
+         in("x8") 64,
+         inlateout("x0") 1 => _,
+         in("x1") buffer,
+         in("x2") count,
+         options(nostack, preserves_flags)
+    )
+}
+
+pub unsafe fn sys_sleep(seconds: usize) {
+    let sleep_time = timespec {
+        tv_sec:  seconds as isize,
+        tv_nsec: 0
+    };
+
+    asm!("svc 0", "ret",
+         inlateout("x0") &sleep_time => _,
+         in("x1") 0,
+         in("x8") 101,
+         options(nostack, preserves_flags)
+    )
+}
diff --git a/rs-nap/src/support/interop.rs b/rs-nap/src/support/interop.rs
new file mode 100644
index 0000000..02220fe
--- /dev/null
+++ b/rs-nap/src/support/interop.rs
@@ -0,0 +1,5 @@
+#[repr(C)]
+pub struct timespec {
+    pub tv_sec:  isize,
+    pub tv_nsec: isize,
+}
diff --git a/rs-nap/src/support/x86_64.rs b/rs-nap/src/support/x86_64.rs
index c77d87d..62e231a 100644
--- a/rs-nap/src/support/x86_64.rs
+++ b/rs-nap/src/support/x86_64.rs
@@ -1,4 +1,17 @@
 use core::arch::asm;
+use core::slice::from_raw_parts as mkslice;
+
+mod interop;
+use interop::timespec;
+
+#[no_mangle]
+#[naked]
+unsafe extern "C" fn _start() {
+    // Move the stack pointer before it gets clobbered
+    asm!("mov rdi, rsp",
+         "call get_args",
+         options(noreturn))
+}
 
 pub unsafe fn sys_exit(exit_code:usize) -> ! {
     asm!("syscall",
@@ -20,12 +33,6 @@ pub unsafe fn sys_write(buffer: *const u8, count: usize) {
     )
 }
 
-#[repr(C)]
-struct timespec {
-    pub tv_sec:  isize,
-    pub tv_nsec: isize,
-}
-
 pub unsafe fn sys_sleep(seconds: usize) {
     let sleep_time = timespec {
         tv_sec:  seconds as isize,
diff --git a/rust-toolchain.toml b/rust-toolchain.toml
index 1ea7d64..440fdae 100644
--- a/rust-toolchain.toml
+++ b/rust-toolchain.toml
@@ -1,4 +1,7 @@
 [toolchain]
 channel = "nightly"
 components = [ "rustfmt", "clippy" ]
-targets = [ "x86_64-unknown-linux-gnu" ]
+targets = [
+  "x86_64-unknown-linux-gnu",
+  "aarch64-unknown-linux-gnu"
+]

From e1029a6100f6f623bd0104fe9bccc57bbc2f4cef Mon Sep 17 00:00:00 2001
From: Jonathan DeMarks <jmdemarks@spscommerce.com>
Date: Mon, 25 Sep 2023 11:09:40 -0500
Subject: [PATCH 3/9] simplification and arm64 working

---
 rs-nap/src/main.rs            | 34 +++++++++++++++++-----------------
 rs-nap/src/support/aarch64.rs | 20 ++++++++++----------
 2 files changed, 27 insertions(+), 27 deletions(-)

diff --git a/rs-nap/src/main.rs b/rs-nap/src/main.rs
index 08a34a8..967cc17 100644
--- a/rs-nap/src/main.rs
+++ b/rs-nap/src/main.rs
@@ -9,34 +9,34 @@ use core::slice::from_raw_parts as mkslice;
 #[no_mangle]
 pub unsafe fn nap(args: &[*const u8]) -> ! {
     let mut sleep_time:usize = 10;
+    let mut good_input:bool = false;
 
-    if args.len() < 2 {
-        sleep(sleep_time, false);
-    } else {
-        let (seconds,_) = from_radix_10(mkslice(args[1], strlen(args[1])));
-        let mut good_input = seconds > 0 && seconds < 1000000000;
-
-        if good_input {
-            sleep_time = seconds;
-        } else {
-            good_input = false;
-        }
-
-        sleep(sleep_time, good_input);
+    if args.len() > 1 {
+        (sleep_time, good_input) = get_sleep_time(args[1]);
     }
 
+    sleep(sleep_time, good_input);
+
     print_str(b"Done!\n");
-    sys_exit(0);
+    sys_exit(0)
 }
 
-pub unsafe fn sleep(seconds: usize, good_input: bool) {
+pub unsafe fn sleep(mut sleep_time: usize, good_input: bool) {
     if good_input == false {
+        sleep_time = 10;
         print_str(b"Bad input. ");
     }
+
     print_str(b"Sleeping for ");
-    print_num(seconds);
+    print_num(sleep_time);
     print_str(b" seconds...\n");
-    sys_sleep(seconds)
+
+    sys_sleep(sleep_time);
+}
+
+unsafe fn get_sleep_time(arg: *const u8) -> (usize, bool) {
+    let (seconds,_) = from_radix_10(mkslice(arg, strlen(arg)));
+    (seconds, seconds > 0 && seconds < 1000000000)
 }
 
 #[no_mangle]
diff --git a/rs-nap/src/support/aarch64.rs b/rs-nap/src/support/aarch64.rs
index 1a3d2d9..b7ab2fb 100644
--- a/rs-nap/src/support/aarch64.rs
+++ b/rs-nap/src/support/aarch64.rs
@@ -1,5 +1,4 @@
 use core::arch::asm;
-use core::slice::from_raw_parts as mkslice;
 
 mod interop;
 use interop::timespec;
@@ -16,19 +15,20 @@ unsafe extern "C" fn _start() {
 
 pub unsafe fn sys_exit(exit_code:usize) -> ! {
     asm!("svc 0",
-         in("x8") 93,
+         in("w8") 93,
          in("x0") exit_code,
          options(nostack, noreturn)
     )
 }
 
 pub unsafe fn sys_write(buffer: *const u8, count: usize) {
-    asm!("svc 0", "ret",
-         in("x8") 64,
-         inlateout("x0") 1 => _,
-         in("x1") buffer,
-         in("x2") count,
-         options(nostack, preserves_flags)
+    asm!("mov  x0, #1",
+         "mov  x1, {buffer}",
+         "mov  x2, {count}",
+         "mov  x8, #64",
+         "svc #0",
+         buffer = in(reg) buffer,
+         count = in(reg) count
     )
 }
 
@@ -38,8 +38,8 @@ pub unsafe fn sys_sleep(seconds: usize) {
         tv_nsec: 0
     };
 
-    asm!("svc 0", "ret",
-         inlateout("x0") &sleep_time => _,
+    asm!("svc 0",
+         in("x0") &sleep_time,
          in("x1") 0,
          in("x8") 101,
          options(nostack, preserves_flags)

From b32f24203c88127ae47296d1e12f96a4c92400a4 Mon Sep 17 00:00:00 2001
From: Jonathan DeMarks <jmdemarks@spscommerce.com>
Date: Mon, 25 Sep 2023 11:09:40 -0500
Subject: [PATCH 4/9] simplification and arm64 working

---
 rs-nap/README.md | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/rs-nap/README.md b/rs-nap/README.md
index 9d0886c..64681f5 100644
--- a/rs-nap/README.md
+++ b/rs-nap/README.md
@@ -14,6 +14,22 @@
 - [x] x86_64 implementation
 - [x] aarch64 implementation
 
+#### Architecture specific implementation notes
+
+For each new architecture:
+
+1. Add a file to the `support` subfolder which implements
+   - The startup code (`_start`) to get arguments from the stack
+   - and the following linux kernel service calls
+     - `sys_exit` to call `exit`
+     - `sys_write` to call `write` to stdout 1
+     - and `sys_sleep`
+2. Add a platform specific entry to `support.rs` in the form of a `cfg_attr`
+3. Add a platform target to `.cargo/config.toml`
+4. Add a toolchain target to `rust-toolchain.toml`
+5. Update this `README.md` with the new platform build and run commands
+6. Update any CI/CD (future) to build the binary for the target platform
+
 ## Run on a native processor
 
 ```sh

From 1ccb36c31e3c50e62680950eb44359c02b7f8b18 Mon Sep 17 00:00:00 2001
From: Jonathan DeMarks <jmdemarks@spscommerce.com>
Date: Mon, 25 Sep 2023 13:37:36 -0500
Subject: [PATCH 5/9] fix for register clobbering

---
 rs-nap/src/support/aarch64.rs | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/rs-nap/src/support/aarch64.rs b/rs-nap/src/support/aarch64.rs
index b7ab2fb..329c736 100644
--- a/rs-nap/src/support/aarch64.rs
+++ b/rs-nap/src/support/aarch64.rs
@@ -22,13 +22,17 @@ pub unsafe fn sys_exit(exit_code:usize) -> ! {
 }
 
 pub unsafe fn sys_write(buffer: *const u8, count: usize) {
-    asm!("mov  x0, #1",
-         "mov  x1, {buffer}",
-         "mov  x2, {count}",
-         "mov  x8, #64",
-         "svc #0",
-         buffer = in(reg) buffer,
-         count = in(reg) count
+    asm!(
+        "mov  x0, #1",
+        "mov  x1, {buffer}",
+        "mov  x2, {count}",
+        "mov  x8, #64",
+        "svc #0",
+        buffer = inout(reg) buffer => _,
+        count = inout(reg) count => _,
+        out("x0") _,
+        out("x8") _,
+        options(nostack)
     )
 }
 

From 4f518b4a2488a864aa64209e9a5957f04bff38a6 Mon Sep 17 00:00:00 2001
From: Jonathan DeMarks <jmdemarks@spscommerce.com>
Date: Mon, 25 Sep 2023 13:56:37 -0500
Subject: [PATCH 6/9] Clean up sys_write implementation

---
 rs-nap/src/support/aarch64.rs | 15 +++++----------
 1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/rs-nap/src/support/aarch64.rs b/rs-nap/src/support/aarch64.rs
index 329c736..3efe150 100644
--- a/rs-nap/src/support/aarch64.rs
+++ b/rs-nap/src/support/aarch64.rs
@@ -22,16 +22,11 @@ pub unsafe fn sys_exit(exit_code:usize) -> ! {
 }
 
 pub unsafe fn sys_write(buffer: *const u8, count: usize) {
-    asm!(
-        "mov  x0, #1",
-        "mov  x1, {buffer}",
-        "mov  x2, {count}",
-        "mov  x8, #64",
-        "svc #0",
-        buffer = inout(reg) buffer => _,
-        count = inout(reg) count => _,
-        out("x0") _,
-        out("x8") _,
+    asm!("svc #0",
+        inout("x0") 1 => _,
+        inout("x1") buffer => _,
+        inout("x2") count => _,
+        inout("x8") 64 => _,
         options(nostack)
     )
 }

From 1d59284aabb1e782c4e1bbd052803f7f3e82f45c Mon Sep 17 00:00:00 2001
From: Jonathan DeMarks <jmdemarks@spscommerce.com>
Date: Wed, 18 Dec 2024 14:24:20 -0600
Subject: [PATCH 7/9] Update to latest Rust specs

---
 rs-nap/src/support/aarch64.rs | 11 ++++++-----
 rs-nap/src/support/x86_64.rs  | 10 +++++-----
 2 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/rs-nap/src/support/aarch64.rs b/rs-nap/src/support/aarch64.rs
index 3efe150..d430bb1 100644
--- a/rs-nap/src/support/aarch64.rs
+++ b/rs-nap/src/support/aarch64.rs
@@ -1,4 +1,4 @@
-use core::arch::asm;
+use core::arch::{asm,naked_asm};
 
 mod interop;
 use interop::timespec;
@@ -7,10 +7,11 @@ use interop::timespec;
 #[naked]
 unsafe extern "C" fn _start() {
     // Move the stack pointer before it gets clobbered
-    asm!("mov fp, sp",
-         "mov x0, fp",
-         "bl get_args",
-         options(noreturn))
+    naked_asm!(
+        "mov fp, sp",
+        "mov x0, fp",
+        "bl get_args"
+    )
 }
 
 pub unsafe fn sys_exit(exit_code:usize) -> ! {
diff --git a/rs-nap/src/support/x86_64.rs b/rs-nap/src/support/x86_64.rs
index 62e231a..beb0a64 100644
--- a/rs-nap/src/support/x86_64.rs
+++ b/rs-nap/src/support/x86_64.rs
@@ -1,5 +1,4 @@
-use core::arch::asm;
-use core::slice::from_raw_parts as mkslice;
+use core::arch::{asm,naked_asm};
 
 mod interop;
 use interop::timespec;
@@ -8,9 +7,10 @@ use interop::timespec;
 #[naked]
 unsafe extern "C" fn _start() {
     // Move the stack pointer before it gets clobbered
-    asm!("mov rdi, rsp",
-         "call get_args",
-         options(noreturn))
+    naked_asm!(
+        "mov rdi, rsp",
+        "call get_args"
+    )
 }
 
 pub unsafe fn sys_exit(exit_code:usize) -> ! {

From 51a01d11728f7062214c7213734395ad7698cb2e Mon Sep 17 00:00:00 2001
From: Jonathan DeMarks <jmdemarks@spscommerce.com>
Date: Wed, 18 Dec 2024 14:24:42 -0600
Subject: [PATCH 8/9] Add rust output to GH action build

---
 .github/workflows/main.yml | 28 +++++++----------------
 Makefile                   | 15 +++---------
 run-tests.sh               | 47 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 58 insertions(+), 32 deletions(-)
 create mode 100755 run-tests.sh

diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index e7f16a0..d73a4f5 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -12,30 +12,18 @@ jobs:
       - name: Install dependencies
         run: |
           sudo apt-get update -y
-          sudo apt-get install -y make nasm binutils binutils-aarch64-linux-gnu
+          sudo apt-get install -y curl make nasm qemu-user-static \
+               gcc-x86-64-linux-gnu binutils-x86-64-linux-gnu \
+               gcc-aarch64-linux-gnu binutils-aarch64-linux-gnu
+          curl https://sh.rustup.rs -sSf | sh -s -- -y
 
-      - name: Build via Makefile
-        run: make ci_build
+      - name: Build and Test
+        run: |
+          . "$HOME/.cargo/env"
+          make -s ci_tests
 
       - name: Public artifact
         uses: actions/upload-artifact@v1
         with:
           name: Build Artifact
           path: out/
-
-  test:
-    runs-on: ubuntu-latest
-    timeout-minutes: 10
-    steps:
-      - name: Checkout Repo
-        uses: actions/checkout@v2
-
-      - name: Install dependencies
-        run: |
-          sudo apt-get update -y
-          sudo apt-get install -y make nasm binutils binutils-aarch64-linux-gnu
-          sudo wget https://github.com/multiarch/qemu-user-static/releases/download/v7.1.0-2/qemu-aarch64-static -O /usr/sbin/qemu-aarch64-static
-          sudo chmod +x /usr/sbin/qemu-aarch64-static
-
-      - name: Run Tests
-        run: make ci_tests
diff --git a/Makefile b/Makefile
index 5fd520f..5887c8c 100644
--- a/Makefile
+++ b/Makefile
@@ -9,21 +9,12 @@ ci_build:
 	x86_64-linux-gnu-ld -m elf_x86_64 -z noseparate-code -z noexecstack --strip-all -o out/nap nap.o && rm nap.o
 	aarch64-linux-gnu-as nap-aarch64.s -o nap-aarch64.o
 	aarch64-linux-gnu-ld -z noseparate-code -z noexecstack --strip-all -o out/nap-aarch64 nap-aarch64.o && rm nap-aarch64.o
+	cargo build --release --target-dir target --target x86_64-unknown-linux-gnu && cp target/x86_64-unknown-linux-gnu/release/rs-nap out/rs-nap-x86_64
+	cargo build --release --target-dir target --target aarch64-unknown-linux-gnu && cp target/aarch64-unknown-linux-gnu/release/rs-nap out/rs-nap-aarch64
 	ls -la out/
 
 ci_tests: ci_build
-	if [ $$(arch) = "x86_64" ]; then \
-		echo "[x86_64] Testing 1s nap"; \
-		timeout 3s out/nap 1 2>&1 > /dev/null; \
-		echo "[x86_64] Testing 10s default/bad input nap"; \
-		timeout 12s out/nap bad_arg ; if [ $$? = "1" ]; then true; else false; fi; \
-	else \
-		echo "x86_64 testing not available on aarch64 platform"; \
-	fi
-	echo "[aarch64] Testing 1s nap"
-	timeout 3s qemu-aarch64-static out/nap-aarch64 1 2>&1 > /dev/null
-	echo "[aarch64] Testing 10s default/bad input nap"
-	timeout 12s qemu-aarch64-static out/nap-aarch64 bad_arg ; if [ $$? = "1" ]; then true; else false; fi
+	@bash run-tests.sh
 
 tests: install
 	if [ $$(arch) = "x86_64" ]; then \
diff --git a/run-tests.sh b/run-tests.sh
new file mode 100755
index 0000000..812731f
--- /dev/null
+++ b/run-tests.sh
@@ -0,0 +1,47 @@
+#!/bin/bash
+set -euo pipefail
+
+# Runs a qemu test for a given architecture
+# Ideally all builds will use the method below
+run_qemu() {
+  local arch=$1
+  local seconds=$2
+  local binary=$3
+  local qemu="qemu-$arch-static"
+  if [[ $binary == *"rs-"* ]]; then
+    icon="🦀"
+  else
+    icon="🦬"
+  fi
+
+  echo "$icon $arch - Testing ${seconds}s nap"
+  time timeout $(($seconds+1))s $qemu $binary $seconds &>/dev/null
+}
+
+## NASM tests - likely problems in the code somewhere
+
+# NASM amd64 tests (does not work on aarch64 qemu)
+if [ $(arch) == "x86_64" ]; then
+  echo "🦬 x86_64 - Testing 1s nap"
+  timeout 2s ./out/nap 1 &>/dev/null
+  echo "🦬 x86_64 - Testing 10s nap"
+  timeout 11s ./out/nap 10 &>/dev/null
+fi
+
+# NASM arm64 tests (does not work on x86_64 qemu)
+if [ $(arch) == "aarch64" ]; then
+  echo "🦬 aarch64 - Testing 1s nap"
+  timeout 2s ./out/nap-aarch64 1 &>/dev/null
+  echo "🦬 aarch64 - Testing 10s nap"
+  timeout 11s ./out/nap-aarch64 10 &>/dev/null
+fi
+
+## Rust tests - rust works everywhere
+
+# Rust amd64 tests
+run_qemu x86_64 1 ./out/rs-nap-x86_64
+run_qemu x86_64 10 ./out/rs-nap-x86_64
+
+# Rust arm64 tests
+run_qemu aarch64 1 ./out/rs-nap-aarch64
+run_qemu aarch64 10 ./out/rs-nap-aarch64

From 1a971956c3374cad1e359803e58015de833eb0a6 Mon Sep 17 00:00:00 2001
From: Jonathan DeMarks <jmdemarks@spscommerce.com>
Date: Wed, 18 Dec 2024 14:26:21 -0600
Subject: [PATCH 9/9] Mandatory update to v4 upload artifact

---
 .github/workflows/main.yml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index d73a4f5..8070a74 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -22,8 +22,8 @@ jobs:
           . "$HOME/.cargo/env"
           make -s ci_tests
 
-      - name: Public artifact
-        uses: actions/upload-artifact@v1
+      - name: Publish artifact
+        uses: actions/upload-artifact@v4
         with:
           name: Build Artifact
           path: out/