From 3c87632b0cbc4e494747bb508ffd404e6bdc29c2 Mon Sep 17 00:00:00 2001
From: 0x35c <unai64@orange.fr>
Date: Fri, 8 Nov 2024 12:45:00 +0100
Subject: [PATCH] wip: change the C function set_mem_size to asm

---
 headers/memory.h    |  2 +-
 src/boot.s          |  8 +++++---
 src/kernel.c        |  7 ++++---
 src/memory/memory.c |  2 +-
 src/set_mem_size.s  | 27 +++++++++++++++++++++++++++
 5 files changed, 38 insertions(+), 8 deletions(-)
 create mode 100644 src/set_mem_size.s

diff --git a/headers/memory.h b/headers/memory.h
index e13978c..4968a94 100644
--- a/headers/memory.h
+++ b/headers/memory.h
@@ -23,7 +23,7 @@ extern uint32_t _kernel_end;
 extern uint32_t boot_page_directory;
 extern uint32_t *page_directory;
 extern uint32_t page_table_default[1024];
-extern uint32_t mem_size;
+extern uint64_t mem_size;
 
 uint32_t *virt_to_phys(uint32_t *virt_addr);
 void init_memory(void);
diff --git a/src/boot.s b/src/boot.s
index 3eeb36c..8215bf4 100644
--- a/src/boot.s
+++ b/src/boot.s
@@ -34,6 +34,7 @@ boot_page_table1:
 # The kernel entry point.
 .section .multiboot.text, "a"
 .global _start
+.global end_mem
 .type _start, @function
 _start:
 	# Physical address of boot_page_table1.
@@ -89,6 +90,10 @@ _start:
 	movl $(boot_page_directory - 0xC0000000), %ecx
 	movl %ecx, %cr3
 
+	jmp set_mem_size
+
+end_mem:
+
 	# Enable paging and the write-protect bit.
 	movl %cr0, %ecx
 	orl $0x80000000, %ecx
@@ -113,9 +118,6 @@ _start:
 	# Set up the stack.
 	mov $stack_top, %esp
 
-	push %eax
-	push %ebx
-
 	# Enter the high-level kernel.
 	call kernel_main
 
diff --git a/src/kernel.c b/src/kernel.c
index 7e96de6..a11fb10 100644
--- a/src/kernel.c
+++ b/src/kernel.c
@@ -31,7 +31,8 @@
  * feeling qui me donnerait envie de continuer dans une relation "couple" sur le
  * long terme. Je sais pas trop comment le dire sans que ça te blesse, c'est pas
  * personnel ou quoi c'est cool quand on parle et tout mais juste je ne pense
- * pas pouvoir faire marcher une relation comme celle là :( */ /* Voilà je voulais juste te le dire pour pas que tu te mettes quelque chose en
+ * pas pouvoir faire marcher une relation comme celle là :( */
+/* Voilà je voulais juste te le dire pour pas que tu te mettes quelque chose en
  * tête qui n'arrivera pas, je trouve ça plus correct */
 
 static void set_mem_size(multiboot_info_t *mbd, uint32_t magic)
@@ -54,14 +55,14 @@ static void set_mem_size(multiboot_info_t *mbd, uint32_t magic)
 	}
 }
 
-void kernel_main(multiboot_info_t *mbd, uint32_t magic)
+void kernel_main(void)
 {
 	terminal_initialize();
 	init_gdt();
 	init_idt();
 	init_memory();
 	load_drivers();
-	set_mem_size(mbd, magic);
+	/* set_mem_size(mbd, magic); */
 	kprintf(KERN_ALERT
 	        "I see no way to confuse an array of 256 seg:off pairs with a "
 	        "complex 8*unknown quantity -byte descriptor table. -- Troy "
diff --git a/src/memory/memory.c b/src/memory/memory.c
index 3d31152..4e79a69 100644
--- a/src/memory/memory.c
+++ b/src/memory/memory.c
@@ -6,7 +6,7 @@
 
 uint32_t *page_directory = &boot_page_directory;
 uint32_t page_table_default[1024] __attribute__((aligned(4096)));
-uint32_t mem_size;
+uint64_t mem_size;
 
 void init_memory(void)
 {
diff --git a/src/set_mem_size.s b/src/set_mem_size.s
new file mode 100644
index 0000000..dcd4c42
--- /dev/null
+++ b/src/set_mem_size.s
@@ -0,0 +1,27 @@
+.intel_syntax noprefix
+
+.section .text
+	.global set_mem_size
+	
+	set_mem_size:
+		xor ebx, ebx
+.L1:
+		// loop condition
+		cmp ebx, [eax + 64]
+		jge end_mem
+		
+		// declare mmmt
+		mov ecx, [eax + 68]
+		add ecx, ebx
+
+		// check if the mmmt->type is available (1)
+		cmp DWORD PTR [ecx + 20], 1
+		jne .L2
+		// add the size of the block
+		mov edx, [ecx + 12]
+		add DWORD PTR mem_size, edx
+		mov edx, [ecx + 16]
+		add DWORD PTR mem_size + 4, edx
+.L2:
+		add ebx, 24
+		jmp .L1