Hybrid

build.sh

@@ -8,10 +8,7 @@ nasm pure64.asm -o ../bin/pure64.sys -l ../bin/pure64-debug.txt
 
 cd boot
 
-nasm mbr.asm -o ../../bin/mbr.sys
-nasm pxestart.asm -o ../../bin/pxestart.sys
-nasm multiboot.asm -o ../../bin/multiboot.sys
-nasm multiboot2.asm -o ../../bin/multiboot2.sys
-nasm uefi.asm -o ../../bin/uefi.sys
+nasm bios.asm -o ../../bin/bios.sys -l ../../bin/bios-debug.txt
+nasm uefi.asm -o ../../bin/uefi.sys -l ../../bin/uefi-debug.txt
 
 cd ../..

docs/README.md

@@ -73,19 +73,19 @@ OUTPUT_ARCH("i386:x86-64")
 
 SECTIONS
 {
-    . = 0x100000;
-    .text : {
-        *(.text)
-    }
-    .data : {
-        *(.data)
-    }
-    .rodata : {
-        *(.rodata)
-    }
-    .bss : {
-        *(.bss)
-    }
+	. = 0x100000;
+	.text : {
+		*(.text)
+	}
+	.data : {
+		*(.data)
+	}
+	.rodata : {
+		*(.rodata)
+	}
+	.bss : {
+		*(.bss)
+	}
 }
 
 ```
@@ -108,7 +108,7 @@ extern int main(void);
 
 void _start(void)
 {
-    main();
+	main();
 }
 ```
 This file would **always** have to be linked in front of everything else. For the above example that would mean the linker command above would have to become:
@@ -231,13 +231,14 @@ MPS INTI flags:
 <tr><td>Trigger Mode</td><td>2</td><td>2</td><td>01 Edge-triggered, 11 Level-triggered</td></tr>
 </table>
 
-A copy of the E820 System Memory Map is stored at memory address `0x0000000000006000`. Each E820 record is 32 bytes in length and the memory map is terminated by a blank record.
+A copy of the UEFI System Memory Map is stored at memory address `0x0000000000006000`. Each UEFI record is 48 bytes in length and the memory map is terminated by a blank record.
 <table border="1" cellpadding="2" cellspacing="0">
 <tr><th>Variable</th><th>Variable Size</th><th>Description</th></tr>
-<tr><td>Starting Address</td><td>64-bit</td><td>The starting address for this record</td></tr>
-<tr><td>Length</td><td>64-bit</td><td>The length of memory for this record</td></tr>
-<tr><td>Memory Type</td><td>32-bit</td><td>Type 1 is usable memory, Type 2 is not usable</td></tr>
-<tr><td>Extended Attributes</td><td>32-bit</td><td>ACPI 3.0 Extended Attributes bitfield</td></tr>
-<tr><td>Padding</td><td>64-bit</td><td>Padding for 32-byte alignment</td></tr>
+<tr><td>Type</td><td>64-bit</td><td>The type of the memory region</td></tr>
+<tr><td>Physical Start</td><td>64-bit</td><td>Physical Address - 4K aligned</td></tr>
+<tr><td>Virtual Start</td><td>64-bit</td><td>Virtual Address - 4K aligned</td></tr>
+<tr><td>NumberOfPages</td><td>64-bit</td><td>The number of 4K pages in this section</td></tr>
+<tr><td>Attribute</td><td>64-bit</td><td>See document linked below</td></tr>
+<tr><td>Padding</td><td>64-bit</td><td>Padding</td></tr>
 </table>
-For more information on the E820 Memory Map: <a href="http://wiki.osdev.org/Detecting_Memory_%28x86%29">OSDev wiki on E820</a>
+For more information on the UEFI Memory Map: <a href="https://uefi.org/specs/UEFI/2.9_A/07_Services_Boot_Services.html#efi-boot-services-getmemorymap">UEFI Specs</a>

src/boot/pxestart.asm → src/boot/bios-pxe.asm

@@ -17,6 +17,9 @@
 ; kernel64.sys	16384 bytes (or so)
 ; =============================================================================
 
+; Set the desired screen resolution values below
+Horizontal_Resolution		equ 800
+Vertical_Resolution		equ 600
 
 BITS 16
 org 0x7C00
@@ -31,10 +34,10 @@ start:
 	mov sp, 0x7C00
 	sti				; Enable interrupts
 
-	mov ah, 0
-	mov al, 11100011b		; 9600bps, no parity, 1 stop bit, 8 data bits
-	mov dx, 0			; Serial port 0
-	int 0x14			; Configure serial port
+;	mov ah, 0
+;	mov al, 11100011b		; 9600bps, no parity, 1 stop bit, 8 data bits
+;	mov dx, 0			; Serial port 0
+;	int 0x14			; Configure serial port
 
 ; Get the BIOS E820 Memory Map
 ; use the INT 0x15, eax= 0xE820 BIOS function to get a memory map
@@ -133,6 +136,8 @@ check_A20:
 	mov si, msg_OK
 	call print_string_16
 
+	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
@@ -230,4 +235,4 @@ VBEModeInfoBlock.PhysBasePtr		equ VBEModeInfoBlock + 40	; DD - physical address
 VBEModeInfoBlock.Reserved1		equ VBEModeInfoBlock + 44	; DD - Reserved - always set to 0
 VBEModeInfoBlock.Reserved2		equ VBEModeInfoBlock + 48	; DD - Reserved - always set to 0
 
-; EOF
+; EOF

src/boot/mbr.asm → src/boot/bios.asm

@@ -13,15 +13,53 @@
 ; Default location of the second stage boot loader. This loads
 ; 32 KiB from sector 16 into memory at 0x8000
 %define DAP_SECTORS 64
-%define DAP_STARTSECTOR 16
+%define DAP_STARTSECTOR 262160
 %define DAP_ADDRESS 0x8000
 %define DAP_SEGMENT 0x0000
 
+; Set the desired screen resolution values below
+Horizontal_Resolution		equ 800
+Vertical_Resolution		equ 600
 
 BITS 16
 org 0x7C00
 
 entry:
+	jmp bootcode
+	nop
+
+; BPB (BIOS Parameter Block)
+dq 0		; OEM identifier
+dw 0		; Bytes per sector
+db 0		; Sectors per cluster
+dw 0		; Reserved sectors
+db 0		; Number of FATs
+dw 0		; Number of root directory entries
+dw 0		; The total sectors in the logical volume
+db 0		; Media descriptor type
+dw 0		; Number of sectors per FAT
+dw 0		; Number of sectors per track
+dw 0		; Number of heads or sides on the storage media
+dd 0		; Number of hidden sectors
+dd 0		; Large sector count
+
+; EBPB (Extended Boot Record)
+dd 0		; Sectors per FAT
+dw 0		; Flags
+dw 0		; FAT version number
+dd 0		; The cluster number of the root directory
+dw 0		; The sector number of the FSInfo structure
+dw 0		; The sector number of the backup boot sector
+dq 0		; Reserved
+dd 0		; Reserved
+db 0		; Drive number
+db 0		; Flags in Windows NT
+db 0		; Signature
+dd 0		; Volume ID 'Serial' number
+times 11 db 0	; Volume label string
+dq 0		; System identifier string. Always "FAT32   "
+
+bootcode:
 	cli				; Disable interrupts
 	cld				; Clear direction flag
 	xor eax, eax
@@ -33,11 +71,6 @@ entry:
 
 	mov [DriveNumber], dl		; BIOS passes drive number in DL
 
-	mov ah, 0
-	mov al, 11100011b		; 9600bps, no parity, 1 stop bit, 8 data bits
-	mov dx, 0			; Serial port 0
-	int 0x14			; Configure serial port
-
 ; Get the BIOS E820 Memory Map
 ; use the INT 0x15, eax= 0xE820 BIOS function to get a memory map
 ; inputs: es:di -> destination buffer for 24 byte entries
@@ -104,8 +137,8 @@ check_A20:
 	mov al, 0xDF
 	out 0x60, al
 
-	mov si, msg_Load
-	call print_string_16
+;	mov si, msg_Load
+;	call print_string_16
 
 	mov cx, 0x4000 - 1		; Start looking from here
 VBESearch:
@@ -121,9 +154,9 @@ VBESearch:
 	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], 800 ; Desired XRes here
+	cmp word [VBEModeInfoBlock.XResolution], Horizontal_Resolution ; Desired XRes here
 	jne VBESearch
-	cmp word [VBEModeInfoBlock.YResolution], 600 ; Desired YRes here
+	cmp word [VBEModeInfoBlock.YResolution], Vertical_Resolution ; Desired YRes here
 	jne VBESearch
 
 	or bx, 0x4000			; Use linear/flat frame buffer model (set bit 14)
@@ -140,12 +173,15 @@ VBESearch:
 	jc read_fail
 
 	; Verify that the 2nd stage boot loader was read.
-	mov ax, [0x8006]
-	cmp ax, 0x3436			; Match against the Pure64 binary
-	jne sig_fail
+;	mov ax, [0x8006]
+;	cmp ax, 0x3436			; Match against the Pure64 binary
+;	jne sig_fail
+
+	mov bl, 'B'			; 'B' as we booted via BIOS
+;	mov [0x5FFF], al		; Store the boot marker
 
-	mov si, msg_OK
-	call print_string_16
+;	mov si, msg_OK
+;	call print_string_16
 
 	; At this point we are done with real mode and BIOS interrupts. Jump to 32-bit mode.
 	cli				; No more interrupts
@@ -156,12 +192,12 @@ VBESearch:
 	jmp 8:0x8000			; Jump to 32-bit protected mode
 
 read_fail:
-	mov si, msg_ReadFail
-	call print_string_16
-	jmp halt
+;	mov si, msg_ReadFail
+;	call print_string_16
+;	jmp halt
 sig_fail:
-	mov si, msg_SigFail
-	call print_string_16
+;	mov si, msg_SigFail
+;	call print_string_16
 halt:
 	hlt
 	jmp halt
@@ -171,19 +207,19 @@ halt:
 ;------------------------------------------------------------------------------
 ; 16-bit function to output a string to the serial port
 ; IN:	SI - Address of start of string
-print_string_16:			; Output string in SI to screen
-	pusha
-	mov dx, 0			; Port 0
-.repeat:
-	mov ah, 0x01			; Serial - Write character to port
-	lodsb				; Get char from string
-	cmp al, 0
-	je .done			; If char is zero, end of string
-	int 0x14			; Output the character
-	jmp short .repeat
-.done:
-	popa
-	ret
+;print_string_16:			; Output string in SI to screen
+;	pusha
+;	mov dx, 0			; Port 0
+;.repeat:
+;	mov ah, 0x01			; Serial - Write character to port
+;	lodsb				; Get char from string
+;	cmp al, 0
+;	je .done			; If char is zero, end of string
+;	int 0x14			; Output the character
+;	jmp short .repeat
+;.done:
+;	popa
+;	ret
 ;------------------------------------------------------------------------------
 
 align 16
@@ -198,31 +234,30 @@ dw 0xFFFF, 0x0000, 0x9A00, 0x00CF	; 32-bit code descriptor
 dw 0xFFFF, 0x0000, 0x9200, 0x00CF	; 32-bit data descriptor
 gdt32_end:
 
-msg_Load db 10, "MBR ", 0
-msg_OK db "OK", 0
-msg_SigFail db "- Bad Sig!", 0
-msg_ReadFail db "Failed to read drive!", 0
+align 4
 
-times 446-$+$$ db 0
+DAP:
+db 0x10
+db 0x00
+dw DAP_SECTORS
+dw DAP_ADDRESS
+dw DAP_SEGMENT
+dq DAP_STARTSECTOR
 
-; False partition table entry required by some BIOS vendors.
-db 0x80, 0x00, 0x01, 0x00, 0xEB, 0xFF, 0xFF, 0xFF, 0x00, 0x00, 0x00, 0x00, 0xFF, 0xFF, 0xFF, 0xFF
 DriveNumber db 0x00
 
-times 476-$+$$ db 0
+;msg_Load db 10, "MBR ", 0
+;msg_OK db "OK", 0
+;msg_SigFail db "- Bad Sig!", 0
+;msg_ReadFail db "Failed to read!", 0
 
-align 4
+times 446-$+$$ db 0
 
-DAP:
-	db 0x10
-	db 0x00
-	dw DAP_SECTORS
-	dw DAP_ADDRESS
-	dw DAP_SEGMENT
-	dq DAP_STARTSECTOR
+; Partition entries (4x 16-bytes)
 
 times 510-$+$$ db 0
 
+; Boot signature
 sign dw 0xAA55
 
 VBEModeInfoBlock: equ 0x5F00