From a9fb6013db52e231fa2446fd8c512f5e5e92e4d3 Mon Sep 17 00:00:00 2001
From: Nathan Lee <me@nwlee.tech>
Date: Sat, 26 Sep 2026 23:11:30 -0500
Subject: add boot_args support

---
 website-emu/src/lib.rs | 75 +++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 74 insertions(+), 1 deletion(-)

(limited to 'website-emu/src')

diff --git a/website-emu/src/lib.rs b/website-emu/src/lib.rs
index b29c901..9abffa0 100644
--- a/website-emu/src/lib.rs
+++ b/website-emu/src/lib.rs
@@ -21,6 +21,22 @@ extern "C" {
     fn uart_push_line(line: &str);
 }
 
+#[repr(C)]
+#[derive(Clone,Copy)]
+struct BootArgs {
+    cmd_line: u32,
+    devices: u32
+}
+
+#[repr(C)]
+#[derive(Clone,Copy)]
+struct Device {
+    device_type: u8,
+    start: u32,
+    size: u32,
+    next: u32
+}
+
 pub struct Uart {
     pub addr: u32,
     pub value: u8,
@@ -36,6 +52,7 @@ impl MemoryDevice for Uart {
         }
     }
 
+    //noinspection ALL
     fn write(&mut self, address: u32, value: u8) -> Result<(), ()> {
         if address == self.addr {
             self.value = value;
@@ -105,10 +122,66 @@ pub fn boot(image: &[u8], initrd: &[u8], memory: &[u8]) {
     );
 
     let mut state = CpuState::new(cpu_memory);
+    let cmd_line = format!(
+        "mmu=false initrd=initramfs.cpio,{} image=vmwebkrnl.bin,{} iomem=relaxed",
+        INITRD_LOAD,
+        OS_LOAD
+    );
+
+
+    let args_size = size_of::<BootArgs>() as u32;
+    let device_size = size_of::<Device>() as u32;
+
+    let dram_device = Device {
+        device_type: 0, // DRAM
+        start: DRAM_LOAD,
+        size: memory_len as u32,
+        next: DRAM_LOAD + args_size + device_size
+    };
+    let uart_device = Device {
+        device_type: 1, // UART
+        start: CONSOLE_LOAD,
+        size: 1,
+        next: 0
+    };
+    let args = BootArgs {
+        cmd_line: DRAM_LOAD + args_size + device_size * 2,
+        devices: DRAM_LOAD + args_size
+    };
+
+    let args_bytes: &[u8] = unsafe {
+        std::slice::from_raw_parts(
+            &args as *const BootArgs as *const u8,
+            size_of::<BootArgs>(),
+        )
+    };
+    let dram_bytes: &[u8] = unsafe {
+        std::slice::from_raw_parts(
+            &dram_device as *const Device as *const u8,
+            size_of::<Device>(),
+        )
+    };
+    let uart_bytes: &[u8] = unsafe {
+        std::slice::from_raw_parts(
+            &uart_device as *const Device as *const u8,
+            size_of::<Device>(),
+        )
+    };
+    let cmd_line_bytes = cmd_line.as_bytes();
+    for i in 0..args_size {
+        state.memory.write(DRAM_LOAD + i, args_bytes[i as usize]).unwrap();
+    }
+    for i in 0..device_size {
+        state.memory.write(DRAM_LOAD + args_size + i, dram_bytes[i as usize]).unwrap();
+        state.memory.write(DRAM_LOAD + args_size + device_size + i, uart_bytes[i as usize]).unwrap();
+    }
+    for i in 0..cmd_line.len() as u32 {
+        state.memory.write(DRAM_LOAD + args_size + device_size * 2 + i, cmd_line_bytes[i as usize]).unwrap();
+    }
 
     state.pc = 0x80000000;
     state.registers[10] = 0;
-    state.registers[2] = DRAM_LOAD + memory_len as u32;
+    state.registers[11] = DRAM_LOAD;
 
     while state.on {
         {
-- 
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