long mode achieved, starting rust

kernel-rs/src/arch/x86_64/boot.asm

@@ -1,4 +1,5 @@
 global start
+extern long_mode_start
 
 section .text
 bits 32
@@ -12,6 +13,11 @@ start:
 	call	set_up_page_tables
 	call	enable_paging
 
+	; load the 64-bit GDT
+	lgdt	[gdt64.pointer]
+
+	jmp		gdt64.code:long_mode_start
+
 	; print 'OK' to screen
 	mov		dword [0xb8000], 0x2f4b2f4f
 	hlt	
@@ -138,3 +144,12 @@ p2_table:
 stack_bottom:
 	resb	64
 stack_top:
+
+section .rodata
+gdt64:
+	dq 0		; zero entry
+.code: equ $ - gdt64
+	dq (1<<43) | (1<<44) | (1<<47) | (1<<53)	; code segment
+.pointer:
+	dw $ - gdt64 - 1
+	dq gdt64

kernel-rs/src/arch/x86_64/long_mode_init.asm

@@ -0,0 +1,16 @@
+global long_mode_start
+
+section .text
+bits 64
+long_mode_start:
+	; load 0 into all data segment registers
+	mov		ax, 0
+	mov		ss, ax
+	mov		ds, ax
+	mov		es, ax
+	mov		fs, ax
+	mov		gs, ax
+	;print 'OKAY' to screen
+	mov		rax, 0x2f592f412f4b2f4f
+    mov		qword [0xb8000], rax
+    hlt