agrega pasaje real mode a protected

Author: federicogramos

asm/bios/mbr2.asm asm/bios/mbr2_DELETE.asmasm/bios/mbr2.asm renamed to asm/bios/mbr2_DELETE.asm

@@ -1,15 +1,143 @@
-;;;Pasaje 16 to 64 bits
+;;==============================================================================
+;; 
+;;==============================================================================
 
-	mov [p_BootDisk], bh		; Save disk from where system was booted from
+;; Primera parte: pasa real mode a protected mode.
 
-	mov eax, 16			; Set the correct segment registers
+
+start16:
+
+
+
+; Get the BIOS E820 Memory Map
+; https://wiki.osdev.org/Detecting_Memory_(x86)#BIOS_Function:_INT_0x15,_EAX_=_0xE820
+; The code below is from https://wiki.osdev.org/Detecting_Memory_(x86)#Getting_an_E820_Memory_Map
+; inputs: es:di -> destination buffer for 24 byte entries
+; outputs: bp = entry count, trashes all registers except esi
+; The function below creates a memory map at address 0x6000 and the records are:
+; 64-bit Base
+; 64-bit Length
+; 32-bit Type (1 = normal, 2 reserved, ACPI reclaimable)
+; 32-bit ACPI
+; 64-bit Padding
+do_e820:
+	mov edi, 0x00006000		; location that memory map will be stored to
+	xor ebx, ebx			; ebx must be 0 to start
+	xor bp, bp			; keep an entry count in bp
+	mov edx, 0x0534D4150		; Place "SMAP" into edx
+	mov eax, 0xe820
+	mov [es:di + 20], dword 1	; force a valid ACPI 3.X entry
+	mov ecx, 24			; ask for 24 bytes
+	int 0x15
+	jc nomemmap			; carry set on first call means "unsupported function"
+	mov edx, 0x0534D4150		; Some BIOSes apparently trash this register?
+	cmp eax, edx			; on success, eax must have been reset to "SMAP"
+	jne nomemmap
+	test ebx, ebx			; ebx = 0 implies list is only 1 entry long (worthless)
+	je nomemmap
+	jmp jmpin
+e820lp:
+	mov eax, 0xe820			; eax, ecx get trashed on every int 0x15 call
+	mov [es:di + 20], dword 1	; force a valid ACPI 3.X entry
+	mov ecx, 24			; ask for 24 bytes again
+	int 0x15
+	jc memmapend			; carry set means "end of list already reached"
+	mov edx, 0x0534D4150		; repair potentially trashed register
+jmpin:
+	jcxz skipent			; skip any 0 length entries
+	cmp cl, 20			; got a 24 byte ACPI 3.X response?
+	jbe notext
+	test byte [es:di + 20], 1	; if so: is the "ignore this data" bit clear?
+	je skipent
+notext:
+	mov ecx, [es:di + 8]		; get lower dword of memory region length
+	test ecx, ecx			; is the qword == 0?
+	jne goodent
+	mov ecx, [es:di + 12]		; get upper dword of memory region length
+	jecxz skipent			; if length qword is 0, skip entry
+goodent:
+	inc bp				; got a good entry: ++count, move to next storage spot
+	add di, 32			; Pad to 32 bytes for each record
+skipent:
+	test ebx, ebx			; if ebx resets to 0, list is complete
+	jne e820lp
+nomemmap:
+memmapend:
+	xor eax, eax			; Create a blank record for termination (32 bytes)
+	mov ecx, 8
+	rep stosd
+
+; Enable the A20 gate
+set_A20:
+	in al, 0x64
+	test al, 0x02
+	jnz set_A20
+	mov al, 0xD1
+	out 0x64, al
+check_A20:
+	in al, 0x64
+	test al, 0x02
+	jnz check_A20
+	mov al, 0xDF
+	out 0x60, al
+
+	mov cx, 0x4000 - 1		; Start looking from here
+VBESearch:
+	inc cx
+	mov bx, cx			; Mode is saved to BX for the set command later
+	cmp cx, 0x5000
+	je halt
+	mov edi, VBEModeInfoBlock	; VBE data will be stored at this address
+	mov ax, 0x4F01			; VESA SuperVGA BIOS - GET SuperVGA MODE INFORMATION - http://www.ctyme.com/intr/rb-0274.htm
+	int 0x10
+	cmp ax, 0x004F			; Return value in AX should equal 0x004F if command supported and successful
+	jne VBESearch			; Try next mode
+	cmp byte [VBEModeInfoBlock.BitsPerPixel], 32 ; Desired bit depth
+	jne VBESearch			; If not equal, try next mode
+	cmp word [VBEModeInfoBlock.XResolution], Horizontal_Resolution ; Desired XRes here
+	jne VBESearch
+	cmp word [VBEModeInfoBlock.YResolution], Vertical_Resolution ; Desired YRes here
+	jne VBESearch
+	or bx, 0x4000			; Use linear/flat frame buffer model (set bit 14)
+	mov ax, 0x4F02			; VESA SuperVGA BIOS - SET SuperVGA VIDEO MODE - http://www.ctyme.com/intr/rb-0275.htm
+	int 0x10
+	cmp ax, 0x004F			; Return value in AX should equal 0x004F if supported and successful
+	jne halt
+
+
+
+
+
+	mov bl, 'B'			; 'B' as we booted via BIOS
+
+	; At this point we are done with real mode and BIOS interrupts. Jump to 32-bit mode.
+	cli				; No more interrupts
+	lgdt [cs:GDTR32]		; Load GDT register
+	mov eax, cr0
+	or al, 0x01			; Set protected mode bit
+	mov cr0, eax
+	;;jmp 8:0x8000			; Jump to 32-bit protected mode
+jmp 8:0x8000
+
+;;;;;;;;;;;;;;; here ends mbr completion
+
+
+
+
+
+
+;;;Pasaje 32 to 64 bits
+start32:
+	mov [p_BootDisk], bh		;; Save disk from where system was booted from
+
+	mov eax, 16			;; Set the correct segment registers
 	mov ds, ax
 	mov es, ax
 	mov ss, ax
 	mov fs, ax
 	mov gs, ax
 
-	xor eax, eax			; Clear all registers
+	xor eax, eax			;; Clear all registers
 	xor ebx, ebx
 	xor ecx, ecx
 	xor edx, edx

asm/bios/start16.asm

@@ -238,21 +238,16 @@ ap_sleep:
 
 BITS 32
 
-nop
-nop
-nop
 bootmode_branch:
-;;jmp start32
-
+	jmp start64
 
-	cmp bl, 'U'	;; If uefi boot then already in 64 bit mode.
-	jne start32
+	;;cmp bl, 'U'	;; If uefi boot then already in 64 bit mode.
 	;;je start64
-	jmp start64
+
 	;;cmp bl, 'B'	;; If bios boot, currently 32 bits, goto configure 64 bit mode.
-	;;je start32
+	;;je start__________________32
 
-start32:
+;;start______________________32:
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
@@ -261,7 +256,7 @@ start32:
 ;; genera corrimiento de memoria o no entra donde debe entrar porque script ld tsl.ld reporta overlap.
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
-%include "./asm/bios/start16.asm"
+;;%include "./asm/bios/start16.asm"
 
 
 
@@ -276,9 +271,9 @@ start32:
 
 
 
-%ifdef BIOS
-%include "./asm/bios/bios_32_64.asm"
-%endif
+;;%ifdef BIOS
+;;%include "./asm/bios/bios_32_64.asm"
+;;%endif
 
 
 ;;==============================================================================