Some file restructuring

2026-11-03 18:22:22 +00:00 · 2024-10-10 10:03:58 +02:00
parent 886a802cc1
commit 63ecaec569
16 changed files with 3228 additions and 11 deletions
@@ -0,0 +1,472 @@
+[bits 16]
+[org 0x7e00]
+
+%define STAGE3_LOC 0x50000
+%define MODE_INFO_BLOCK_LOC 0x6000
+
+start:
+    mov [driveNum], dl
+
+    ; Physical memory map setup
+    xor ax, ax
+    mov es, ax
+
+memMapEntries equ 0x7000
+getMemoryMap:
+    mov di, memMapEntries + 4 ; 4 bytes after memMapEntries
+    xor ebx, ebx
+    xor bp, bp
+    mov edx, "PAMS" ; SMAP in little endian
+    mov eax, 0xe820
+    mov dword [es:di+20], 1 ; Force valid ACPI 3.X entry
+    mov ecx, 24
+    int 0x15
+    jc .error
+
+    cmp eax, "PAMS"
+    jne .error
+    test ebx, ebx
+    jnz .start
+
+.error:
+    stc
+    jmp inputGfx
+
+.nextEntry:
+    mov edx, "PAMS" ; In case BIOS messes with edx
+    mov ecx, 24
+    mov eax, 0xe820
+    int 0x15
+
+.start:
+    jcxz .skipEntry
+    mov ecx, [es:di+8] ; Low 32 bits of length
+    or ecx, [es:di+12] ; High 32 bits of length
+    jz .skipEntry
+
+    ; Valid entry
+    inc bp
+    add di, 24 ; Next entry
+
+.skipEntry:
+    test ebx, ebx
+    jz .done
+    jmp .nextEntry
+
+.done:
+    mov [memMapEntries], bp
+    clc
+
+;; Get graphics values from user (resolution etc.)
+inputGfx:
+    xor ecx, ecx
+    cmp word [width], 0 ; Values already set
+    jne vbeSetup
+    mov si, gfxChooseMsg
+    call print
+    call getNumber ; Stores input value in bx
+    mov [width], bx
+
+    mov si, gfxHeightMsg
+    call print
+    call getNumber
+    mov [height], bx
+
+    mov si, gfxBppMsg
+    call print
+    call getNumber
+    mov [bpp], bx
+
+vbeSetup:
+    ; Setup VBE info
+    xor ax, ax
+    mov es, ax
+    mov ax, 0x4f00
+    mov di, vbeInfoBlock
+    int 0x10
+
+    cmp ax, 0x4f
+    jne error
+
+    mov ax, word [vbeInfoBlock.videoModePtr]
+    mov [offset], ax
+    mov ax, word [vbeInfoBlock.videoModePtr+2]
+    mov [_segment], ax
+
+    mov fs, ax
+    mov si, [offset]
+
+;; Get next VBE mode
+.findMode:
+    mov dx, [fs:si]
+    inc si
+    inc si
+    mov [offset], si
+    mov [mode], dx
+
+    cmp dx, 0xffff ; Indicates end of modes
+    je .endOfModes
+
+    mov ax, 0x4f01 ; Get VBE mode info
+    mov cx, [mode]
+    mov di, modeInfoBlock
+    int 0x10
+
+    cmp ax, 0x4f
+    jne error
+
+    ; Print values (Debug)
+    ; mov ax, [modeInfoBlock.xRes]
+    ; ror ax, 8
+    ; call printHex
+    ; ror ax, 8
+    ; call printHex
+    ; mov ax, 0x0e20
+    ; int 0x10
+    ; mov ax, [modeInfoBlock.yRes]
+    ; ror ax, 8
+    ; call printHex
+    ; ror ax, 8
+    ; call printHex
+    ; mov ax, 0x0e20
+    ; int 0x10
+    ; xor ax, ax
+    ; mov al, [modeInfoBlock.bpp]
+    ; call printHex
+    ; mov ax, 0x0e20
+    ; int 0x10 
+    ; mov al, 0x0a
+    ; int 0x10
+    ; mov al, 0x0d
+    ; int 0x10
+
+    ; Check if it is the right mode
+    mov ax, [width]
+    cmp ax, [modeInfoBlock.xRes]
+    jne .nextMode
+
+    mov ax, [height]
+    cmp ax, [modeInfoBlock.yRes]
+    jne .nextMode
+    
+    mov al, [bpp]
+    cmp al, [modeInfoBlock.bpp]
+    jne .nextMode
+
+    ; Set VBE mode
+    mov ax, 0x4f02
+    mov bx, [mode]
+    or bx, 0x4000 ; Set 14th bit to 1
+    xor di, di
+    int 0x10
+
+    cmp ax, 0x4f
+    jne error
+
+    jmp loadGDT
+
+.nextMode:
+    mov ax, [_segment]
+    mov fs, ax
+    mov si, [offset]
+    jmp .findMode
+    
+.endOfModes:
+    mov ax, 0x03
+    int 0x10 ; Clear screen
+    mov si, gfxModeNotFoundErr
+    call print
+    mov word [width], 0 ; Unset values
+    jmp inputGfx
+
+error:
+    mov si, vbeErr
+    call print
+    cli
+    hlt
+
+;; Load the global descriptor table (GDT)
+loadGDT:
+    cli
+    lgdt [GDT_Descriptor]
+    ; Enable protected mode
+    mov eax, cr0
+    or eax, 1
+    mov cr0, eax
+
+    ; Far jump to 32 bit mode!!
+    jmp CODE_SEG:protected_start
+
+;;
+;; Prints a hex byte
+;; al - value to print
+;;
+printHex:
+    push ax
+    push bx
+    
+    mov bh, 2
+    mov bl, al
+    and al, 0xf0
+    ror al, 4
+    mov ah, 0x0e ; For printing
+.printNibble:
+    cmp al, 10
+    jl .print
+    add al, 39
+.print:
+    add al, 48 ; ASCII Char
+    int 0x10
+    dec bh
+    jz .done
+    mov al, bl
+    and al, 0x0f
+    jmp .printNibble
+.done:
+    pop bx
+    pop ax
+    ret
+
+;;
+;; Prints a null terminated string
+;; si - pointer to string
+;;
+print:
+    push ax
+    mov ah, 0x0e
+.loop:
+    lodsb ; mov al, [si]   inc si
+    cmp al, 0
+    je .done
+    int 0x10
+    jmp .loop
+.done:
+    pop ax
+    ret
+
+;;
+;; Reads a base 10 number as input from user
+;; Returns:
+;;  bx - number read
+;;
+getNumber: ; TODO: if user enters a number that overflows (n > 0xffff) shit breaks
+    push cx
+    push ax
+    push dx
+    xor bx, bx
+    mov cx, 10
+.nextDigit:
+    xor ah, ah
+    int 0x16
+    mov ah, 0x0e
+
+    cmp al, 0x08 ; Backspace
+    je .backspace
+    cmp al, 0x0d ; Enter
+    je .enter
+
+    cmp al, '0' ; Make sure user entered a number
+    jl .nextDigit
+    cmp al, '9' 
+    jg .nextDigit
+
+    int 0x10 ; Print the digit
+
+    sub al, '0' ; Convert to integer
+    mov ah, 0
+    imul bx, bx, 10 ; bx *= 10
+    add bx, ax ; bx += ax
+    jmp .nextDigit
+
+.backspace:
+    cmp bx, 0 ; Check if we can backspace
+    je .nextDigit 
+    int 0x10 ; go back one space
+
+    mov ax, bx
+    xor dx, dx
+    div cx      ; dx:ax / cx -> ax = result, dx = remainder
+    mov bx, ax
+
+    mov ah, 0x0e
+    mov al, ' ' 
+    int 0x10
+    mov al, 0x08
+    int 0x10
+
+    jmp .nextDigit
+
+.enter:
+    pop dx
+    pop ax
+    pop cx
+    ret
+
+;; 32 Bit entry code
+[bits 32]
+protected_start:
+    ; Set up data and stack segments
+    mov ax, DATA_SEG 
+    mov ds, ax 
+    mov ss, ax 
+    mov es, ax
+    mov fs, ax
+    mov gs, ax
+    
+    ; Set up the stack pointer in protected mode
+    mov ebp, 0x90000
+    mov esp, ebp
+
+    ; Store VBE Mode Info Block in memory
+    mov esi, modeInfoBlock
+    mov edi, MODE_INFO_BLOCK_LOC ; Destination
+    mov ecx, 64 ; 64 * 4 = 256B (size of modeInfoBlock)
+    rep movsd
+
+    ; Perform The far jump
+    jmp CODE_SEG:STAGE3_LOC
+
+;; Data
+driveNum: db 0
+
+vbeErr: db "VBE Error!", 0
+acpiFuncErr: db "ACPI Function not supported!", 0
+
+gfxChooseMsg: db "Please enter desired values" ; No NULL terminator, we want to print gfxWidthMsg right after anyway
+gfxWidthMsg: db 0x0a, 0x0d, "Width: ", 0
+gfxHeightMsg: db 0x0a, 0x0d, "Height: ", 0
+gfxBppMsg: db 0x0a, 0x0d, "Bits Per Pixel: ", 0
+gfxModeNotFoundErr: db "Mode not found! ", 0
+
+;; GDT
+GDT:
+.start:
+    .nullDescriptor:    ; No clue why this exists
+        dd 0
+        dd 0
+    .codeDescriptor:    ; Memory for code
+        dw 0xffff       ; First 16 bits of limit
+        dw 0            ; 16 bits +
+        db 0            ; + 8 bits = 24 bits
+        db 0b10011010   ; p, dpl, s, type flags
+        db 0b11001111   ; Other flags, last 4 bits of limit
+        db 0            ; Base
+    .dataDescriptor:    ; Memory for data
+        dw 0xffff       ; First 16 bits of limit
+        dw 0            ; 16 bits +
+        db 0            ; + 8 bits = 24 bits
+        db 0b10010010   ; p, dpl, s, type flags
+        db 0b11001111   ; Other flags, last 4 bits of limit
+        db 0            ; Base
+.end:
+
+GDT_Descriptor:
+    dw GDT.end - GDT.start - 1  ; Size
+    dd GDT.start        ; GDT Pointer
+
+CODE_SEG equ GDT.codeDescriptor - GDT.start
+DATA_SEG equ GDT.dataDescriptor - GDT.start
+
+;; VBE Stuff
+; Default width
+%ifndef DEF_W
+%define DEF_W 0
+%endif
+; Default height
+%ifndef DEF_H
+%define DEF_H 0
+%endif
+; Default bpp
+%ifndef DEF_BPP
+%define DEF_BPP 0
+%endif
+; Use defaults
+%ifdef DEF_RES
+width: dw DEF_W
+%else
+width: dw 0
+%endif
+height: dw DEF_H
+bpp: db DEF_BPP
+
+offset: dw 0
+_segment: dw 0 ; segment is a keyword
+mode: dw 0
+
+times (512*2)-($-$$) db 0 ; End Sector 2
+
+;; Sector 2
+vbeInfoBlock:
+    .vbeSigniture: db "VBE2"
+    .vbeVersion: dw 0x0300 ; BCD Version
+    .oemStringPtr: dd 0
+    .capibilities: dd 0
+    .videoModePtr: dd 0
+    .totalMemory: dw 0
+    .oemSoftwareRev: dw 0
+    .oemVendorNamePtr: dd 0
+    .oemProductNamePtr: dd 0
+    .oemProductRevisionPtr: dd 0
+    .reserved: times 222 db 0
+    .oemData: times 256 db 0
+
+;; Sector 3
+modeInfoBlock:
+;; Required by all VBE revisions
+    .modeAttr: dw 0
+    .windowAAtrr: db 0
+    .windowBAttr: db 0
+    .windowGranularity: dw 0
+    .windowSize: dw 0
+    .windowASegment: dw 0
+    .windowBSegment: dw 0
+    .windowFunctionPtr: dd 0
+    .bytesPerScanline: dw 0
+
+;; Required by VBE 1.2+
+    .xRes: dw 0
+    .yRes: dw 0
+    .xCharSize: db 0
+    .yCharSize: db 0
+    .planeCount: db 0
+    .bpp: db 0
+    .bankCount: db 0
+    .memoryModel: db 0
+    .bankSize: db 0
+    .imagePageCount: db 0
+    .reserved1: db 1
+
+;; Direct color fields
+    .redMaskSize: db 0
+    .redFieldPos: db 0
+    .greenMaskSize: db 0
+    .greenFieldPos: db 0
+    .blueMaskSize: db 0
+    .blueFieldPos: db 0
+    .reservedMaskSize: db 0
+    .reservedFieldPos: db 0
+    .directColorModeInfo: db 0
+
+;; Required by VBE 2.0+
+    .physicalBasePtr: dd 0
+    .reserved2: dd 0
+    .reserved3: dw 0
+
+;; Required by VBE 3.0+
+    .linearBytesPerScanline: dw 0
+    .bankImagePageCount: db 0
+    .linearImagePageCount: db 0
+    .linearRedMaskSize: db 0
+    .linearRedFieldPos: db 0
+    .linearGreenMaskSize: db 0
+    .linearGreenFieldPos: db 0
+    .linearBlueMaskSize: db 0
+    .linearBlueFieldPos: db 0
+    .linearReservedMaskSize: db 0
+    .linearReservedFieldPos: db 0
+    .maxPixelClock: dd 0
+
+    .reserved4: times 190 db 0 
+
+times (512*4)-($-$$) db 0
+