wip: change the C function set_mem_size to asm

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