From 5907f488af24c0e1f5d39518accc719a80a53e79 Mon Sep 17 00:00:00 2001
From: Amelia Coutard <eliottulio.coutard@gmail.com>
Date: Mon, 9 May 2022 11:29:54 +0200
Subject: [PATCH] Added operator- to phys_ptr<T>s, which allowed for
 simplifying a bit of the code

---
 src/kernel.cpp | 6 +++---
 src/utils.hpp  | 3 +++
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/src/kernel.cpp b/src/kernel.cpp
index 32ec362..9512d14 100644
--- a/src/kernel.cpp
+++ b/src/kernel.cpp
@@ -91,7 +91,7 @@ extern "C" void kmain(unsigned long magic, os::phys_ptr<const multiboot2::info_s
 							remove_some_mem(
 							s, e, info_start, info_end,
 							[] (auto s, auto e) {
-								page_allocator.deallocate({.ptr = s, .size = (e.get_phys_addr() - s.get_phys_addr()) / 0x1000});
+								page_allocator.deallocate({.ptr = s, .size = std::uint64_t(e - s)});
 							}
 							);
 						}
@@ -114,10 +114,10 @@ extern "C" void kmain(unsigned long magic, os::phys_ptr<const multiboot2::info_s
 
 	// Deallocate multiboot info structure: not usable anymore.
 	if (info_pages_wholly_usable) {
-		page_allocator.deallocate({.ptr = info_start, .size = (info_end.get_phys_addr() - info_start.get_phys_addr()) / 0x1000});
+		page_allocator.deallocate({.ptr = info_start, .size = std::uint64_t(info_end - info_start)});
 	} else if (info_start + 1 < info_end - 1) {
 		// Ignore the first and last blocks: ensures all the RAM is truly usable.
-		page_allocator.deallocate({.ptr = info_start + 1, .size = (info_end.get_phys_addr() - info_start.get_phys_addr()) / 0x1000 - 2});
+		page_allocator.deallocate({.ptr = info_start + 1, .size = std::uint64_t(info_end - info_start - 2)});
 	}
 
 	os::print("RAM:\n");
diff --git a/src/utils.hpp b/src/utils.hpp
index 2f1ae15..5210817 100644
--- a/src/utils.hpp
+++ b/src/utils.hpp
@@ -59,6 +59,9 @@ namespace os {
 		friend constexpr phys_ptr<T> operator-(phys_ptr<T> ptr, std::ptrdiff_t offset) {
 			return phys_ptr<T>{ptr.phys_addr - offset * sizeof(T)};
 		}
+		friend constexpr std::ptrdiff_t operator-(phys_ptr<T> a, phys_ptr<T> b) {
+			return (a.phys_addr - b.phys_addr) / sizeof(T);
+		}
 
 		constexpr std::uintptr_t get_phys_addr() const {
 			return phys_addr;
-- 
2.47.0