find_kernel: improve the iterator handling

Instead of checking if it is the first iteration of the loop in every iteration, handle the first iteration of the modules iterator outside the loop.

src/arch/x86_64/multiboot.rs

@@ -108,23 +108,22 @@ pub fn find_kernel() -> &'static [u8] {
 
 	// Iterate through all modules.
 	// Collect the start address of the first module and the highest end address of all modules.
-	let modules = multiboot
+	let mut module_iter = multiboot
 		.modules()
 		.expect("Could not find a memory map in the Multiboot information");
-	let mut found_module = false;
-	let mut start_address = 0;
-	let mut end_address = 0;
-
-	for m in modules {
-		found_module = true;
-
-		if start_address == 0 {
-			start_address = m.start as usize;
-		}
-
-		if m.end as usize > end_address {
-			end_address = m.end as usize;
-		}
+	let start_address;
+	let mut end_address;
+
+	if let Some(first_module) = module_iter.next() {
+		start_address = first_module.start as usize;
+		info!("Found an ELF module at {:#x}", start_address);
+		end_address = first_module.end as usize;
+	} else {
+		panic!("Could not find a single module in the Multiboot information")
+	}
+	// Find the maximum end address from the remaining modules
+	for m in module_iter {
+		end_address = usize::max(end_address, m.end as usize);
 	}
 
 	info!("Found module: [{:#x} - {:#x}]", start_address, end_address);
@@ -139,12 +138,6 @@ pub fn find_kernel() -> &'static [u8] {
 	PhysAlloc::init(free_memory_address);
 
 	// Identity-map the ELF header of the first module.
-	assert!(
-		found_module,
-		"Could not find a single module in the Multiboot information"
-	);
-	assert!(start_address > 0);
-	info!("Found an ELF module at {:#x}", start_address);
 	paging::map_range::<Size4KiB>(
 		start_address,
 		start_address,