X-Git-Url: https://git.ucc.asn.au/?a=blobdiff_plain;f=Kernel%2Farch%2Fx86_64%2Fstart32.asm;h=4769ee498e0063122a64031bb0fb40a142cbaabc;hb=4bc68df387ca7de4a0616d779509e5ebc05d0de4;hp=eada7b999a2d48ffb22215e929edd01d286b4775;hpb=b98fbd4e9c71447d81fc9bd643fb174c76346e0f;p=tpg%2Facess2.git

diff --git a/Kernel/arch/x86_64/start32.asm b/Kernel/arch/x86_64/start32.asm
index eada7b99..4769ee49 100644
--- a/Kernel/arch/x86_64/start32.asm
+++ b/Kernel/arch/x86_64/start32.asm
@@ -1,23 +1,57 @@
 
 [BITS 32]
 
+KERNEL_BASE	equ	0xFFFF800000000000
+
 [section .multiboot]
 mboot:
-	MULTIBOOT_MAGIC	equ	0x1BADB002
-	dd	MULTIBOOT_MAGIC
+	; Multiboot macros to make a few lines later more readable
+	MULTIBOOT_PAGE_ALIGN	equ 1<<0
+	MULTIBOOT_MEMORY_INFO	equ 1<<1
+	MULTIBOOT_AOUT_KLUDGE	equ 1<<16
+	MULTIBOOT_HEADER_MAGIC	equ 0x1BADB002
+	MULTIBOOT_HEADER_FLAGS	equ MULTIBOOT_PAGE_ALIGN | MULTIBOOT_MEMORY_INFO; | MULTIBOOT_AOUT_KLUDGE
+	MULTIBOOT_CHECKSUM	equ -(MULTIBOOT_HEADER_MAGIC + MULTIBOOT_HEADER_FLAGS)
+	
+	; This is the GRUB Multiboot header. A boot signature
+	dd MULTIBOOT_HEADER_MAGIC
+	dd MULTIBOOT_HEADER_FLAGS
+	dd MULTIBOOT_CHECKSUM
+	[extern __load_addr]
+	[extern __bss_start]
+	[extern gKernelEnd]
+	; a.out kludge
+	dd mboot	; Location of Multiboot Header
+	dd __load_addr	; Load address
+	dd __bss_start - KERNEL_BASE	; End of .data
+	dd gKernelEnd - KERNEL_BASE	; End of .bss (and kernel)
+	dd start - KERNEL_BASE	; Entrypoint
 
 [extern start64]
 
 [section .text]
 [global start]
 start:
+	mov [gMultibootMagic - KERNEL_BASE], eax
+	mov [gMultibootPtr - KERNEL_BASE], ebx
+
+	; Check for Long Mode support
+	mov eax, 0x80000000
+	cpuid
+	cmp eax, 0x80000001	; Compare the A-register with 0x80000001.
+	mov eax, 0x80000001
+	cpuid
+    jb .not64bitCapable
+	test edx, 1<<29
+	jz .not64bitCapable
+
 	; Enable PAE
 	mov eax, cr4
 	or eax, 0x80|0x20
 	mov cr4, eax
 
 	; Load PDP4
-	mov eax, gInitialPML4
+	mov eax, gInitialPML4 - KERNEL_BASE
 	mov cr3, eax
 
 	; Enable long/compatability mode
@@ -32,43 +66,69 @@ start:
 	mov cr0, eax
 
 	; Load GDT
-	lgdt [gGDTPtr]
-	mov ax, 0x10
-	mov ss, ax
-	mov ds, ax
-	mov es, ax
-	mov fs, ax
-	mov gs, ax
-
-	jmp 0x08:start64
+	lgdt [gGDTPtr - KERNEL_BASE]
+	jmp 0x08:start64 - KERNEL_BASE
+
+.not64bitCapable:
+	mov ah, 0x0F
+	mov edi, 0xB8000
+	mov esi, csNot64BitCapable - KERNEL_BASE
+
+.loop:
+	lodsb
+	test al, al
+	jz .hlt
+	stosw
+	jmp .loop
+	
+.hlt:
+	jmp .hlt
 
 [section .data]
+[global gGDT]
 gGDT:
 	dd	0,0
-	dd	0x00000000, 0x00209800	; 64-bit Code
-	dd	0x00000000, 0x00009000	; 64-bit Data
+	dd	0x00000000, 0x00209A00	; 0x08: 64-bit Code
+	dd	0x00000000, 0x00009200	; 0x10: 64-bit Data
+	dd	0x00000000, 0x0020FA00	; 0x18: 64-bit User Code
+	dd	0x00000000, 0x0000F200	; 0x20: 64-bit User Data
+	dd	0x00000000, 0x0040FA00	; 0x38: 32-bit User Code
+	dd	0x00000000, 0x0040F200	; 0x30: 32-bit User Data
+	times MAX_CPUS	dd	0, 0, 0, 0	; 0x38+16*n: TSS 0
 gGDTPtr:
 	dw	$-gGDT-1
-	dd	gGDT
+	dd	gGDT-KERNEL_BASE
+	dd	0
+[global gMultibootPtr]
+[global gMultibootMagic]
+gMultibootMagic:
+	dd	0
+gMultibootPtr:
 	dd	0
 
 [section .padata]
-gInitialPML4:	; 256 TiB
-	dd	gInitialPDP + 3, 0	; Identity Map Low 4Mb
+[global gInitialPML4]
+gInitialPML4:	; Covers 256 TiB (Full 48-bit Virtual Address Space)
+	dd	gInitialPDP - KERNEL_BASE + 3, 0	; Identity Map Low 4Mb
 	times 256-1 dq	0
-	dd	gInitialPDP + 3, 0	; Identity Map Low 4Mb to kernel base
-	times 256-1 dq 0
-
-gInitialPDP:	; 512 GiB
-	dd	gInitialPD + 3, 0
-	times 511 dq	0
-
-gInitialPD:	; 1 GiB
-	dd	gInitialPT1 + 3, 0
-	dd	gInitialPT2 + 3, 0
-
-gInitialPT1:	; 2 MiB
-	%assign i 1
+	dd	gInitialPDP - KERNEL_BASE + 3, 0	; Map Low 4Mb to kernel base
+	times 256-1-4 dq 0
+	dd	gInitialPML4 - KERNEL_BASE + 3, 0	; Fractal Mapping
+	dq	0
+	dq	0
+	dq	0
+
+gInitialPDP:	; Covers 512 GiB
+	dd	gInitialPD - KERNEL_BASE + 3, 0
+	times 511	dq	0
+
+gInitialPD:	; Covers 1 GiB
+	dd	gInitialPT1 - KERNEL_BASE + 3, 0
+	dd	gInitialPT2 - KERNEL_BASE + 3, 0
+	times 510	dq	0
+
+gInitialPT1:	; Covers 2 MiB
+	%assign i 0
 	%rep 512
 	dq	i*4096+3
 	%assign i i+1
@@ -81,3 +141,6 @@ gInitialPT2:	; 2 MiB
 	%endrep
 
 
+[section .rodata]
+csNot64BitCapable:
+	db "Not 64-bit Capable",0