Usually, the bootloader starts executing programs from a layer called 16-bit real mode, which allows the use of BIOS interrupts. However, in this mode, the accessible memory area and computational capability remain similar to those of a 16-bit machine. To utilize more computational resources and the corresponding memory access, it is necessary to enable the A20 line and transition to 32-bit mode. Particularly for providing graphical functionalities, more computational resources are required.
By enabling the A20 line, the accessible memory area extends beyond 1MB, and transitioning to 32-bit mode offers enhanced computational capabilities. Note that enabling 32-bit mode requires activating protection mode, which disables the use of BIOS interrupts. In this example, BIOS interrupt handling tasks are completed before transitioning to 32-bit mode, and after the transition, an image is rendered in the center of the screen.
<?php
use PHPOS\OS\CodeInfo;
require __DIR__ . '/vendor/autoload.php';
$image = new \PHPOS\Service\Component\Image\Image(
// NOTE: Specify if you want to render an image path
// Only available the file size belows 4KB.
__DIR__ . '/doc/logo.png',
);
//
// Create kernel -----------------------------------------------------------------------------
//
$kernel = new \PHPOS\OS\Code(
new \PHPOS\Architecture\Architecture(
// Use x86_64 architecture
\PHPOS\Architecture\ArchitectureType::x86_64,
),
);
$kernel
// Set code name
->setName('kernel')
// Set 16 bit real mode
->setBits(\PHPOS\OS\BitType::BIT_16)
// Set kernel origin
->setOrigin(0x1000)
// Set compiled kernel size (floor(filesize / 512))
->setSectors(floor(CodeInfo::CODE_BLOCK_SIZE_BITS_16 / \PHPOS\OS\OSInfo::PAGE_SIZE))
// Enable A20 line
->registerService(\PHPOS\Service\BIOS\EnableA20Line::class)
->registerService(\PHPOS\Service\BIOS\Standard\Segment\SetupSegments::class)
->registerService(\PHPOS\Service\BIOS\VESABIOSExtension\SetVESABIOSExtension::class)
->registerService(\PHPOS\Service\BIOS\VESABIOSExtension\SetVESABIOSExtensionInformation::class)
// Transit to 32-bit mode
->registerService(\PHPOS\Service\BIOS\Transit32BitMode::class)
// Load video address after transited to 32-bit mode
->registerService(\PHPOS\Service\BIOS\VESABIOSExtension\LoadVESAVideoAddress::class)
// Set render position
->registerService(
\PHPOS\Service\BIOS\VESABIOSExtension\Renderer\SetRenderPosition::class,
$image->width(),
$image->height(),
\PHPOS\Service\Component\VESA\AlignType::CENTER_CENTER,
)
// Render an image
->registerService(
\PHPOS\Service\BIOS\VESABIOSExtension\Renderer\RenderImageFromInline::class,
$image,
)
->registerService(\PHPOS\Service\BIOS\System\Halt::class)
->registerPostService(\PHPOS\Service\BIOS\GlobalDescriptorTable::class)
// Write code signature
->registerPostService(\PHPOS\Service\BIOS\Disk\CodeSignature::class);
//
// Create bootloader --------------------------------------------------------------------------
//
$bootloader = new \PHPOS\OS\Code(
new \PHPOS\Architecture\Architecture(
// Use x86_64 architecture
\PHPOS\Architecture\ArchitectureType::x86_64,
),
);
// Initialize bootloader
$bootloader
// Set code name
->setName('bootloader')
// Set 16 bit real mode
->setBits(\PHPOS\OS\BitType::BIT_16)
// Set bootloader origin
->setOrigin(\PHPOS\OS\OSInfo::MBR)
// Setup segments (initialize registers for assembly)
->registerService(\PHPOS\Service\BIOS\Standard\Segment\SetupSegments::class)
// Add loading something sector codes
->registerService(\PHPOS\Service\BIOS\System\CallCode::class, $kernel)
// Add bootloader signature
->registerPostService(\PHPOS\Service\BIOS\Bootloader\BootloaderSignature::class);
// Bundle each codes into an OS image
$bundler = new \PHPOS\OS\Bundler\Bundler(
new \PHPOS\OS\ConfigureOption(
__DIR__ . '/dist',
'php-os.img',
$bootloader,
[
$kernel,
],
),
);
// Distribute Makefile and assembly into `dist` directory by the ConfigureOption
$bundler->distribute();;
; _______ ____ ____ _______ ___ ______
; |_ __ \|_ || _||_ __ \ .' `. .' ____ \
; | |__) | | |__| | | |__) |______ / .-. \| (___ \_|
; | ___/ | __ | | ___/|______|| | | | _.____`.
; _| |_ _| | | |_ _| |_ \ `-' /| \____) |
; |_____| |____||____||_____| `.___.' \______.'
;
; Notice: This file is automatically generated by PHP-OS.
; Do not edit this file. We cannot be held responsible if this is edited and overwritten again.
;
[bits 16]
[org 0x1000]
cli
in al, 146
or al, 2
out 146, al
cli
xor ax, ax
xor bx, bx
mov ds, ax
mov es, ax
mov ss, ax
mov sp, 4096
sti
__php_PHPOS_Service_BIOS_VESABIOSExtension_SetVESABIOSExtension:
mov eax, 20226
mov ebx, 16658
int 16
__php_PHPOS_Service_BIOS_VESABIOSExtension_SetVESABIOSExtension_PHPOS_Service_BIOS_VESABIOSExtension_SetVESABIOSExtensionError:
cmp eax, 79
je __php_PHPOS_Service_BIOS_VESABIOSExtension_SetVESABIOSExtension_PHPOS_Service_BIOS_VESABIOSExtension_SetVESABIOSExtensionError_success
mov esi, __php_var_Q291bGQgbm90IHNldCBWRVNBIG1vZGUh
call __php_PHPOS_Service_BIOS_VESABIOSExtension_SetVESABIOSExtension_PHPOS_Service_BIOS_VESABIOSExtension_SetVESABIOSExtensionError_PHPOS_Service_BIOS_IO_PrintConstantString
jmp __php_PHPOS_Service_BIOS_VESABIOSExtension_SetVESABIOSExtension_PHPOS_Service_BIOS_VESABIOSExtension_SetVESABIOSExtensionError_PHPOS_Service_BIOS_IO_PrintConstantString_PHPOS_Service_BIOS_IO_PrintConstantString_PrintDone
__php_PHPOS_Service_BIOS_VESABIOSExtension_SetVESABIOSExtension_PHPOS_Service_BIOS_VESABIOSExtension_SetVESABIOSExtensionError_PHPOS_Service_BIOS_IO_PrintConstantString_PHPOS_Service_BIOS_IO_PrintConstantString_PrintCharacter:
mov ah, 14
mov ebx, 15
int 16
ret
__php_PHPOS_Service_BIOS_VESABIOSExtension_SetVESABIOSExtension_PHPOS_Service_BIOS_VESABIOSExtension_SetVESABIOSExtensionError_PHPOS_Service_BIOS_IO_PrintConstantString:
lodsb
or al, al
jz __php_PHPOS_Service_BIOS_VESABIOSExtension_SetVESABIOSExtension_PHPOS_Service_BIOS_VESABIOSExtension_SetVESABIOSExtensionError_PHPOS_Service_BIOS_IO_PrintConstantString_PHPOS_Service_BIOS_IO_PrintConstantString_PrintDone
call __php_PHPOS_Service_BIOS_VESABIOSExtension_SetVESABIOSExtension_PHPOS_Service_BIOS_VESABIOSExtension_SetVESABIOSExtensionError_PHPOS_Service_BIOS_IO_PrintConstantString_PHPOS_Service_BIOS_IO_PrintConstantString_PrintCharacter
jmp __php_PHPOS_Service_BIOS_VESABIOSExtension_SetVESABIOSExtension_PHPOS_Service_BIOS_VESABIOSExtension_SetVESABIOSExtensionError_PHPOS_Service_BIOS_IO_PrintConstantString
__php_PHPOS_Service_BIOS_VESABIOSExtension_SetVESABIOSExtension_PHPOS_Service_BIOS_VESABIOSExtension_SetVESABIOSExtensionError_PHPOS_Service_BIOS_IO_PrintConstantString_PHPOS_Service_BIOS_IO_PrintConstantString_PrintDone:
ret
hlt
__php_PHPOS_Service_BIOS_VESABIOSExtension_SetVESABIOSExtension_PHPOS_Service_BIOS_VESABIOSExtension_SetVESABIOSExtensionError_success:
__php_PHPOS_Service_BIOS_VESABIOSExtension_SetVESABIOSExtensionInformation:
mov eax, 20225
mov ecx, 16658
mov edi, resb_PHPOS_Service_BIOS_VESABIOSExtension_SetVESABIOSExtensionInformation
int 16
__php_PHPOS_Service_BIOS_Transit32BitMode:
lgdt [__php_PHPOS_Service_BIOS_GlobalDescriptorTable]
mov eax, cr0
or eax, 1
mov cr0, eax
cli
jmp 0x0008:__php_PHPOS_Service_BIOS_Transit32BitMode_32bits_mode
[bits 32]
__php_PHPOS_Service_BIOS_Transit32BitMode_32bits_mode:
cli
mov ax, 16
mov bx, 16
mov ds, ax
mov es, ax
mov ss, ax
mov sp, 4096
__php_PHPOS_Service_BIOS_VESABIOSExtension_LoadVESAVideoAddress:
mov eax, [resb_PHPOS_Service_BIOS_VESABIOSExtension_SetVESABIOSExtensionInformation + 40]
mov edi, eax
add edi, 407790
mov esi, __php_var___php_PHPOS_Service_BIOS_VESABIOSExtension_Renderer_RenderImageFromInline_image
__php_PHPOS_Service_BIOS_VESABIOSExtension_Renderer_Renderer:
mov ecx, 56
__php_PHPOS_Service_BIOS_VESABIOSExtension_Renderer_Renderer_outer:
push ecx
mov ecx, 140
__php_PHPOS_Service_BIOS_VESABIOSExtension_Renderer_Renderer_inner:
__php_PHPOS_Service_BIOS_VESABIOSExtension_Renderer_Renderer_inner_code:
__php_PHPOS_Service_BIOS_VESABIOSExtension_Renderer_RenderPixel:
push ecx
mov ecx, 3
__php_PHPOS_Service_BIOS_VESABIOSExtension_Renderer_RenderPixel_code:
__php_PHPOS_Service_BIOS_VESABIOSExtension_Renderer_RenderImageFromInline_PHPOS_Service_BIOS_VESABIOSExtension_Renderer_RenderImage_copy_pixel_from_destination:
lodsb
mov [edi], al
inc edi
loop __php_PHPOS_Service_BIOS_VESABIOSExtension_Renderer_RenderImageFromInline_PHPOS_Service_BIOS_VESABIOSExtension_Renderer_RenderImage_copy_pixel_from_destination
pop ecx
loop __php_PHPOS_Service_BIOS_VESABIOSExtension_Renderer_Renderer_inner
pop ecx
add edi, 1500
loop __php_PHPOS_Service_BIOS_VESABIOSExtension_Renderer_Renderer_outer
hlt
__php_var_Q291bGQgbm90IHNldCBWRVNBIG1vZGUh:
db "Could not set VESA mode!", 0
__php_var___php_PHPOS_Service_BIOS_VESABIOSExtension_Renderer_RenderImageFromInline_image:
db 215, 101, 163, 215, 101, 163, 215, 101, 163, 215, 101, 163, 215, 101, 163, 215, 101, 163, 215, 101, 163, 215, 101, 163, 215, 101, 163, 215, 101, 163, 215, 101, 163, 215, 101, 163, 215, 101, 163, 215, 101, 163, 215, 101, 163, 215, 101, 163
db 215, 101, 163, 215, 101, 163, 215, 101, 163, 215, 101, 163, 215, 101, 163, 215, 101, 163, 215, 101, 163, 215, 101, 163, 215, 101, 163, 215, 101, 163, 215, 101, 163, 215, 101, 163, 215, 101, 163, 215, 101, 163, 215, 101, 163, 215, 101, 163
; ... omitted
resb_PHPOS_Service_BIOS_VESABIOSExtension_SetVESABIOSExtensionInformation: resb 256
__php_PHPOS_Service_BIOS_GlobalDescriptorTable_null:
dq 0x0000000000000000
__php_PHPOS_Service_BIOS_GlobalDescriptorTable_code:
dw 0xFFFF
dw 0x0000
db 0x00
db 154
db 207
db 0x00
__php_PHPOS_Service_BIOS_GlobalDescriptorTable_data:
dw 0xFFFF
dw 0x0000
db 0x00
db 146
db 207
db 0x00
__php_PHPOS_Service_BIOS_GlobalDescriptorTable_end:
__php_PHPOS_Service_BIOS_GlobalDescriptorTable:
dw __php_PHPOS_Service_BIOS_GlobalDescriptorTable_end - __php_PHPOS_Service_BIOS_GlobalDescriptorTable_null - 1
dd __php_PHPOS_Service_BIOS_GlobalDescriptorTable_null
times 32768-($-$$) db 0