User:Lweb20

Optimized Functions

#define inline __attribute__((always_inline)) inline

inline void* memset(void* ptr, int value, size_t num)
{
	asm("rep stosb": : "a"(value), "c"(num), "D"(ptr));
	return ptr;
}

inline void* memsetw(void* ptr, int value, size_t num)
{
	asm("rep stosw": : "a"(value), "c"(num), "D"(ptr));
	return ptr;
}

inline void* memsetd(void* ptr, int value, size_t num)
{
	asm("rep stosd": : "a"(value), "c"(num), "D"(ptr));
	return ptr;
}

inline void* memcpy(void* destination, const void* source, size_t num)
{
	asm("rep movsb": : "D"(destination), "c"(num), "S"(source));
	return destination;
}

VGA

VGA controllers

The VGA has controllers which in turn have registers to manipulate.

// attribute controller
#define VGA_ATTRIBUTE_CONTROLLER	0x3C0

// sequencer
#define VGA_SEQUENCER			0x3C4

// graphics controller
#define VGA_GRAPHICS_CONTROLLER		0x3CE

// crt controller
#define VGA_CRT_CONTROLLER		0x3D4

Some VGA ports are not associated with a specific controller. They contain a single register.

#define VGA_FEATURE_CONTROL			0x3DA

#define VGA_MISC_REG_WRITE			0x3C2
#define VGA_MISC_REG_READ			0x3CC

Useful functions

Write the registers

inline void vga_attrib_write(unsigned char index, unsigned char value)
{
	inb(VGA_FEATURE_CONTROL);
	outb(VGA_ATTRIBUTE_CONTROLLER, index);
	outb(VGA_ATTRIBUTE_CONTROLLER, value);
}

inline void vga_seq_write(unsigned char index, unsigned char value)
{
	outw(VGA_SEQUENCER, ((unsigned short)value << 8) | index);
}

inline void vga_graphics_write(unsigned char index, unsigned char value)
{
	outw(VGA_GRAPHICS_CONTROLLER, ((unsigned short)value << 8) | index);
}

inline void vga_crtc_write(unsigned char index, unsigned char value)
{
	outw(VGA_CRT_CONTROLLER, ((unsigned short)value << 8) | index);
}


inline void vga_misc_write(unsigned char value)
{
	outb(VGA_MISC_REG_WRITE, value);
}

inline void vga_feature_write(unsigned char value)
{
	outb(VGA_FEATURE_CONTROL, value);
}

To write registers 0 through 7 of the CRT is needed to unlock.

inline void vga_crtc_unlock()
{
	unsigned short data;
	
	outb(VGA_CRT_CONTROLLER, 0x11);
	data = inb(VGA_CRT_CONTROLLER + 1);

	outw(VGA_CRT_CONTROLLER, (ClearBit(data, 7) << 8) | 0x11);
}

inline void vga_crtc_lock()
{
	unsigned short data;
	
	outb(VGA_CRT_CONTROLLER, 0x11);
	data = inb(VGA_CRT_CONTROLLER + 1);

	outw(VGA_CRT_CONTROLLER, (SetBit(data, 7) << 8) | 0x11);
}

Reactivate the screen refresh disabled by writing to the controller attributes.

inline void vga_attrib_active_palette()
{
	outb(VGA_ATTRIBUTE_CONTROLLER, (1 << 5));
}

Read the registers

inline unsigned char vga_attrib_read(unsigned char index)
{
	unsigned char data;
	
	inb(VGA_FEATURE_CONTROL);
	outb(VGA_ATTRIBUTE_CONTROLLER, index);
	data = inb(VGA_ATTRIBUTE_CONTROLLER + 1);
	
	return data;
}

inline unsigned char vga_seq_read(unsigned char index)
{
	outb(VGA_SEQUENCER, index);
	return inb(VGA_SEQUENCER + 1);
}

inline unsigned char vga_graphics_read(unsigned char index)
{
	outb(VGA_GRAPHICS_CONTROLLER, index);
	return inb(VGA_GRAPHICS_CONTROLLER + 1);
}

inline unsigned char vga_crtc_read(unsigned char index)
{
	outb(VGA_CRT_CONTROLLER, index);
	return inb(VGA_CRT_CONTROLLER + 1);
}

inline unsigned char vga_misc_read()
{
	return inb(VGA_MISC_REG_READ);
}

inline unsigned char vga_feature_read()
{
	return inb(VGA_FEATURE_CONTROL);
}

Select plane

inline void vga_select_plane(unsigned char plane)
{
	vga_seq_write(0x02, plane);
}

Wiki Links

Wiki:

http://wiki.osdev.org/OS_Specific_Toolchain

http://wiki.osdev.org/Hosted_GCC_Cross-Compiler

http://wiki.osdev.org/Porting_Newlib

Interrupt Controllers

8259 Programmable Interrupt Controller (PIC)

82489DX Advanced Programmable Interrupt Controller (APIC)

82093AA I/O Advanced Programmable Interrupt Controller (IOAPIC)

Cross Compiling:

http://f.osdev.org/viewtopic.php?f=13&t=18894

IOAPIC:

http://forum.osdev.org/viewtopic.php?t=23774&p=193091

http://forum.osdev.org/viewtopic.php?f=1&t=21745&start=0

SMP:

http://forum.osdev.org/viewtopic.php?f=1&t=23018 (Problems activating SMP on newer (core i5/i7) machines)

http://forum.osdev.org/viewtopic.php?t=28674 (IPI Question)

http://forum.osdev.org/viewtopic.php?f=1&t=23445 (CPUID - how to determine number of physical cores?)

External Links

GZIP file format specification version 4.3

https://tools.ietf.org/html/rfc1952

Qemu Documentation

http://wiki.qemu.org/download/qemu-doc.html

Qemu Monitor

https://en.wikibooks.org/wiki/QEMU/Monitor

Bochs User Manual

http://bochs.sourceforge.net/doc/docbook/user/bochsrc.html

X.org Docs

http://www.x.org/docs/

The little book about OS development

https://littleosbook.github.io/

Linux System Calls

https://sourceware.org/newlib/libc.html#Syscalls

http://man7.org/linux/man-pages/man2/syscalls.2.html

http://syscalls.kernelgrok.com/

SMP

http://www.cheesecake.org/sac/smp.html

X86 architecture

https://en.wikipedia.org/wiki/X86

List of Intel CPU microarchitectures

https://en.wikipedia.org/wiki/List_of_Intel_CPU_microarchitectures

List of AMD CPU microarchitectures

https://en.wikipedia.org/wiki/List_of_AMD_CPU_microarchitectures