Import backup from 2003-12-21

Functions.c

@@ -1,18 +1,21 @@
 //Functions.c
 //05/07/03 Josh Holtrop
 //for HOS
+//Modified: 10/30/03
 
-
+//Writes a byte out to a port
 inline void outportb(unsigned int port, unsigned char value)		// Output a byte to a port
 {
     asm volatile ("outb %%al,%%dx"::"d" (port), "a" (value));
 };
 
+//Writes a word out to a port
 inline void outportw(unsigned int port, unsigned int value)		// Output a word to a port
 {
     asm volatile ("outw %%ax,%%dx"::"d" (port), "a" (value));
 };
 
+//Reads a byte from a port
 inline byte inportb(unsigned short port)
 {
 	unsigned char ret_val;
@@ -23,16 +26,19 @@ inline byte inportb(unsigned short port)
 	return ret_val;
 };
 
-void enable_ints()
+//Enables (SeTs) Interrupt Flag on the processor
+inline void enable_ints()
 {
 	asm("sti");
 };
 
-void disable_ints()
+//Disables (CLears) Interrupt Flag on the processor
+inline void disable_ints()
 {
 	asm("cli");
 };
 
+//Re-maps the Programmable Interrupr Controllers so IRQ0->pic1 base address, IRG8->pic2 base address
 void remap_pics(int pic1, int pic2)
 {
 	byte	a1, a2;
@@ -53,36 +59,82 @@ void remap_pics(int pic1, int pic2)
 	outportb(PIC2_DATA, a2);			//0xA1
 }
 
+//Masks interrupts on first Programmable Interrupt Controller
 inline void pic1_mask(byte mask)
 {
 	outportb(PIC1_DATA, mask);			//0x21, maskfield *OCW1*
 }
 
+//Masks interrupts on second Programmable Interrupt Controller
 inline void pic2_mask(byte mask)
 {
  	outportb(PIC2_DATA, mask);			//0xA1, maskfield *OCW1*
 }
 
+//Restarts the computer
 inline void restart()
 {
+ 	byte temp;
+	do
+	{
+		temp = inportb(0x64);
+		if (temp & 1)
+		inportb(0x60);
+	} while(temp & 2);
+
+
 	outportb (0x64, 0xfe);
 	for (;;)
 	{
 	}
 }
 
-inline void eoi()
+//Halts (freezes) the computer
+inline void halt()
 {
-	outportb(0x20, 0x20);							//EOI
+ 	asm("cli");
+ 	asm("hlt");
+ 	while (1)
+ 	;
 }
 
+//Initializes 8253 Programmable Interrupt Timer
+inline void init_timer()
+{
+ 	//set timer : 2e9c = 100hz
+	outportb(0x43, 0x34);
+	outportb(0x40, 0x9c); //lsb
+	outportb(0x40, 0x2e); //msb
+}
+
+
+//Invalidates the page tables to re-cache the Translation Lookaside Buffer
+/*inline void invlpg()
+{
+	asm("invlpg");
+}*/
+
+//Signals an End Of Interrupt signal to the first PIC
+inline void eoi()
+{
+	outportb(0x20, 0x20);
+}
+
+//Signals an End Of Interrupt signal to both the second and first PIC unit
 inline void eoi2()
 {
  	outportb(0xA0, 0x20);
  	outportb(0x20, 0x20);
 }
 
-
+//Returns the size of the kernel (code & data)
+// - this does not include the bss section
+// - this should be 4kb aligned per the linker script
+// - this should be the size of kernel.bin
+inline dword kernel_size()
+{
+	return (dword)(&_bss)-(dword)(&_code);
+}
 
 
 

asmfuncs.asm

@@ -0,0 +1,45 @@
+; asmfuncs.asm
+; Josh Holtrop
+; 10/23/03
+
+
+;stores the parameter to the CR0 register
+;extern dword write_cr0(dword cr0);
+[global _write_cr0]
+_write_cr0:
+	push	ebp
+	mov	ebp, esp
+	mov	eax, [ebp+8]
+	mov	cr0, eax
+	pop	ebp
+	ret
+
+;returns the value in the CR0 register
+;extern dword read_cr0();
+[global _read_cr0]
+_read_cr0:
+	mov	eax, cr0;
+	ret
+
+;stores the parameter to the CR3 register
+;extern dword write_cr3(dword cr3);
+[global _write_cr3]
+_write_cr3:
+	push	ebp
+	mov	ebp, esp
+	mov	eax, [ebp+8]
+	mov	cr3, eax
+	pop	ebp
+	ret
+
+;returns the value in the CR3 register
+;extern dword read_cr3();
+[global _read_cr3]
+_read_cr3:
+	mov	eax, cr3;
+	ret
+
+
+
+
+

backup.bat

@@ -0,0 +1,19 @@
+@echo off
+echo Backing up to .\Backup\%1
+
+mkdir .\Backup\%1
+mkdir .\Backup\%1\lib
+
+copy *.h .\Backup\%1
+copy *.c .\Backup\%1
+copy *.inc .\Backup\%1
+copy *.asm .\Backup\%1
+copy *.ld .\Backup\%1
+copy *.bat .\Backup\%1
+
+copy .\lib\*.h .\Backup\%1\lib
+copy .\lib\*.c .\Backup\%1\lib
+copy .\lib\*.inc .\Backup\%1\lib
+copy .\lib\*.asm .\Backup\%1\lib
+copy .\lib\*.ld .\Backup\%1\lib
+copy .\lib\*.bat .\Backup\%1\lib

bootdef.inc

@@ -1,12 +1,12 @@
 
-%define VERSION		"0.1.2"			;HOS version
+%define VERSION		"0.12"			;HOS version
 
 %define BOOT_FAT_SEG	0x07E0			;right after boot sector
 %define BOOT_ROOT_SEG	0x0900			;right after FAT
 %define BOOT_KERNEL_SEG	0x0AC0			;right after ROOT_DIR
 %define BOOT_STAGE2_SEG	0x0B00			;right after KERNEL_SEG
 %define BOOT_STAGE2_ADD	0xB000			;address of stage2 to jump to, org at
-%define BOOT_KERNEL_ADD	0x100000		;final pmode kernel destination - physical
+%define BOOT_KERNEL_ADD	0x104000		;final pmode kernel destination - physical
 %define BOOT_RD_ADD	0x200000		;2mb for ram disk
 
 %define BOOT_DATA_SEG	0x9000			;data gathered by stage2 loader goes here

c1.bat

@@ -0,0 +1,2 @@
+nasmw -f aout -o ks.o -l .\lst\kernel.lst kernel.asm
+

c2.bat

@@ -0,0 +1 @@
+gcc -ffreestanding -fno-builtin -nostdlib -nodefaultlibs -c kernel.c -o kernel.o

c3.bat

@@ -0,0 +1 @@
+nasmw -f aout -o asmfuncs.o -l .\lst\asmfuncs.lst asmfuncs.asm

cop.bat

@@ -0,0 +1 @@
+copy kernel.bin a:

cops1.bat

@@ -0,0 +1,2 @@
+rem rawrite -f stage1.bin -d a -n
+partcopy stage1.bin 0 200 -f0

cops2.bat

@@ -0,0 +1 @@
+copy stage2.bin a:

cs1.bat

@@ -0,0 +1 @@
+nasmw -f bin -o stage1.bin -l .\lst\stage1.lst stage1.asm

cs2.bat

@@ -0,0 +1 @@
+nasmw -f bin -o stage2.bin -l .\lst\stage2.lst stage2.asm

fdc.c

@@ -0,0 +1,9 @@
+//fdc.c
+//Author: Josh Holtrop
+//Date: 10/30/03
+
+
+inline	void	fdc_sendDOR(byte dor)
+{
+	outportb(FDC_DOR, dor);
+}

fdc.h

@@ -0,0 +1,12 @@
+//fdc.h
+//Author: Josh Holtrop
+//Date: 10/30/03
+
+
+#define FDC_DOR 0x3f2
+#define FDC_MSR 0x3f4
+
+
+inline	void	fdc_sendDOR(byte dor);
+
+

functions.h

@@ -1,20 +1,28 @@
 //functions.h
 //05/07/03 Josh Holtrop
 //for HOS
+//Modified: 10/30/03
 
-
+extern dword _code;
+extern dword _bss;
+extern dword _end;
 
 inline void outportb(unsigned int port, unsigned char value);
 inline void outportw(unsigned int port, unsigned int value);
 inline byte inportb(unsigned short port);
-void enable_ints();
+inline void enable_ints();
-void disable_ints();
+inline void disable_ints();
 inline void restart();
+inline void halt();
 void remap_pics(int pic1, int pic2);
 inline void pic1_mask(byte mask);
 inline void pic2_mask(byte mask);
 inline void eoi();
 inline void eoi2();
+inline dword kernel_size();
+inline void init_timer();
+//inline void invlpg();
+
 
 
 

gdt.inc

@@ -1,4 +1,7 @@
-
+;gdt.inc
+;Author: Josh Holtrop
+;for HOS
+;Modified: 10/30/03
 
 gdtr:
 	dw	gdt_end-gdt-1

getflop.bat

@@ -0,0 +1 @@
+partcopy -f0 0 168000 flop.img

idt.inc

@@ -1,3 +1,7 @@
+;idt.inc
+;Author: Josh Holtrop
+;for HOS
+;Modified: 10/30/03
 
 idtr:
 	dw	50*8-1		;size of idt

k_defines.h

@@ -1,5 +1,6 @@
 //k_defines.h
 //03/17/03 Josh Holtrop
+//Modified: 10/30/03
 
 #define	PIC1		0x20
 #define	PIC2		0xA0
@@ -29,8 +30,11 @@
 #define BRWHITE_TXT	0x0F
 
 #define FREERAM_START	0x268000
+#define MAX_RAM		0x40000000	//1gb maximum RAM supported
 
-#define KERNEL_PID	0x02
+#define PID_KERNEL	0x02		//kernel's PID
+#define PID_VMM		0x03
+#define PID_USER	0x10000		//user processes' start PID
 
 typedef	unsigned char	byte;
 typedef	unsigned short	word;

kernel.asm

@@ -1,8 +1,11 @@
+;kernel.asm
+;Author: Josh Holtrop
+;Modified: 10/30/03
 
 %include "bootdef.inc"
 
-%define GDT	0x140000
+%define	GDT 0x100000
-%define IDT	0x150000
+%define IDT 0x102000
 
 [global start]
 [extern _isr]
@@ -10,6 +13,7 @@
 
 bits 32
 
+;This is where the kernel begins execution
 start:
 	cli				;if they weren't already off
 	mov	edi, GDT
@@ -38,6 +42,7 @@ fill_idt:
 	mov	esi, ebx
 	add	esi, edx
 	loop	fill_idt
+	mov	word	[IDT+0x30*8+4], 0xEE00	;interrupt 0x30 has user priviledges
 
 	lgdt	[gdtr]			;load gdt
 	jmp	KERNEL_CODE:newgdtcontinue
@@ -52,11 +57,11 @@ newgdtcontinue:
 	lidt	[idtr]			;load idt
 
 	call	_k_init
+haltit:
 	hlt				;halt processor when k_init is done
-	jmp	$			;shouldn't get here...	
+	jmp	haltit			;shouldn't get here...
 
 %include "gdt.inc"
 %include "idt.inc"
 
 
-

kernel.c

@@ -1,93 +1,98 @@
 //kernel.c
 //08/13/03 Josh Holtrop
 //Holtrop's Operating System
+//Version: 0.12
+//Modified: 11/12/03
 
-#define VXR video_mode.XResolution
+#include "k_defines.h"		//#DEFINE's for kernel
-#define VYR video_mode.YResolution
 
-#include "k_defines.h"
+#include "lib/string.h"		//library string functions
+#include "lib/io.h"		//library input/output functions
 
-#include "lib/string.h"
+#include "functions.h"		//general functions
-#include "lib/io.h"
+#include "video.h"		//video functions
-
+#include "mm.h"			//physical memory management functions
-#include "functions.h"
+#include "vmm.h"		//virtual memory management & paging functions
-#include "video.h"
+#include "keyboard.h"		//generic keyboard driver & functions
-#include "mm.h"
+#include "mouse.h"		//generic ps/2 mouse driver & functions
-#include "keyboard.h"
+#include "fdc.h"		//Floppy Disk Controller functions
-#include "mouse.h"
+#include "stdfont.h"		//Standard font bitmask array
 
 void isr(dword num);
 void k_init();
+extern dword write_cr0(dword cr0);
+extern dword read_cr0();
+extern dword write_cr3(dword cr3);
+extern dword read_cr3();
 
+#include "fdc.c"
 #include "mouse.c"
 #include "keyboard.c"
 #include "mm.c"
+#include "vmm.c"
 #include "functions.c"
 #include "video.c"
 
 dword	timer = 0;
+dword	*videoMode;
 
+//Main kernel initialization method
 void k_init()
 {
+		// ===== Initialization
+	fdc_sendDOR(0x0C);		//turn off floppy motor!!
 	console_cls();
 	remap_pics(0x20, 0x28);
-	//set timer : 2e9c = 100hz
+	init_timer();
-	outportb(0x43, 0x34);
-	outportb(0x40, 0x9c); //lsb
-	outportb(0x40, 0x2e); //msb
-	video_init((ModeInfoBlock *) 0x90306);
-	video_rectf(VXR*3/11, 0, VXR*4/11, VYR-1, 0x00000088);      		//test rectangles, draws "HOS"
-	video_rectf(VXR*7/11, 0, VXR*8/11, VYR-1, 0x00000088);
-	video_rectf(VXR/11, 0, VXR*2/11, VYR*2/5, 0x00000088);
-	video_rectf(VXR/11, VYR*3/5, VXR*2/11, VYR-1, 0x00000088);
-	video_rectf(VXR*5/11, VYR/5, VXR*6/11, VYR*4/5, 0x00000088);
-	video_rectf(VXR*9/11, VYR/5, VXR-1, VYR*2/5, 0x00000088);
-	video_rectf(VXR*8/11, VYR*3/5, VXR*10/11, VYR*4/5, 0x00000088);
-
-	video_vert(10, 10, 16, 0x00ffff00);		//should be yellow 'H'
-	video_horiz(13, 10, 14, 0x00ffff00);
-	video_vert(14, 10, 16, 0x00ffff00);
-	
-	video_horiz(10, 17, 21, 0x00ffff00);
-	video_vert(19, 10, 16, 0x00ffff00);
-	video_horiz(16, 17, 21, 0x00ffff00);
-	
-	int a, b;
-	for (a = 0; a < 256; a++)
-	{
-		for (b = 0; b < 256; b++)
-		{
-			video_pset(a+5, b+30, (a<<16)|(b<<8));
-			video_pset(a+270, b+30, (a<<8)|(b));
-			video_pset(a+535, b+30, (a<<16)|(b));
-
-			video_pset(a+5, b+290, (a<<16)|(b<<8)|0x000000ff);
-			video_pset(a+270, b+290, (a<<8)|(b)|0x00ff0000);
-			video_pset(a+535, b+290, (a<<16)|(b)|0x0000ff00);
-		}
-	}
-
 	mm_init();
+	videoMode = (dword *)0x90002;
+	if (*videoMode)
+		video_init((ModeInfoBlock *) 0x90306);
+	vmm_init();
 	mouse_init();
-	enable_ints();
+	vmm_enable_paging();
-	printf("Memory available to OS: %d MB (Bytes: %d)\n", mm_totalmem/0x100000, mm_totalmem);
 	pic1_mask(0);			//unmask IRQ's 0-7
 	pic2_mask(0);			//unmask IRQ's 8-15
+	enable_ints();
+	kbd_resetLEDs();		//after enabling interrupts!!
+	
+	char *bmpptr = (char *)0x108000+54;
+	int a = 0;
+	int x = 0;
+	int y = 479;
+	for (a=0; a < 640*480; a++)
+	{
+		video_pset(x, y, *(dword *)bmpptr);
+		bmpptr += 3;
+		x++;
+		if (x == 640)
+		{
+			x = 0;
+			y--;
+		}
+	}
+
+	printf("HOS 0.12 - Kernel Size: %d kb\n", kernel_size()/1024);
+	printf("Memory available to OS: %d MB (Bytes: %d)\n", mm_totalmem/0x100000, mm_totalmem);
+	printf("Free memory: %d bytes\n", mm_freemem());
+
 	dword key = 0;
 	for (;;)
 	{
 		key = kbdWaitKey();
+		if ((key & 0xFF) > 2)	//key is not a control key
 			putc(key);
 	}
 }
 
+// main Interrupt Service Routine - handles all interrupts unless caught by kernel.asm
 void isr(dword num)
 {
 	switch(num)
 	{
 	case 0x20:         		// IRQ0 - timer interrupt
 		timer++;
-		(*(byte *)0xb8000)++;
+		(*(byte *)(0xb8000))++;
 		eoi();
 		break;
 	case 0x21:  			// IRQ1 - keyboard interrupt

keyboard.c

@@ -1,28 +1,29 @@
 //Keyboard.c
 // Created: 04/17/03 Josh Holtrop
-// Modified: 09/09/03
+// Modified: 10/30/03
 //for HOS
 
 #define KBD_BUFFER_LENGTH 64
 
-byte kbdFlags = 0;
+byte kbdFlags = 0;		//holds current keyboard flags - caps/num/scroll/shift/ctrl/alt
-byte kbdAscii = 0;
+byte kbdAscii = 0;		//holds ASCII value of a key pressed
-byte kbdScan = 0;
+byte kbdScan = 0;		//holds the keyboard scan code of a key pressed
 
-dword kbdBuffer[KBD_BUFFER_LENGTH];
+dword kbdBuffer[KBD_BUFFER_LENGTH];	//a buffer for all keypresses
-int kbdBufferStart = 0;
+int kbdBufferStart = 0;			//position of next key in buffer
-int kbdBufferLen = 0;
+int kbdBufferLen = 0;			//number of keys left in the buffer
-byte kbdExt = 0;
+byte kbdExt = 0;			//# of extended key codes left to input
-byte kbdExt2 = 0;
+byte kbdExt2 = 0;                       //# of 2nd-set-extended key codes left to input
 byte ackReason = 0;		//used to record the reason why we would get an acknowledge byte (0xFA)
 
 
+//these arrays convert a keyboard scan code to an ASCII character value
                                    //nul esc            bksp tab              lctl            lsft            rsft lalt caps F1  F2  F3  F4  F5  F6  F7  F8  F9  F10 numScrlNumPad-------                                  unknown---- F11 F12 unknown....
 const byte SCAN2ASCII[128]      = "\000\0331234567890-=\010\011qwertyuiop[]\n\001asdfghjkl;'`\001\\zxcvbnm,./\001*\001 \001\001\001\001\001\001\001\001\001\001\001\001\001\001\001\001-\001\001\001+\001\001\001\001\001\002\002\002\001\001\002\002\002\002\002\002\002\002\002\002\002\002\002\002\002\002\002\002\002\002\002\002\002\002\002\002\002\002\002\002\002\002\002\002\002\002\002\002\002";
 const byte SCAN2ASCIISHIFT[128] = "\000\033!@#$%^&*()_+\010\011QWERTYUIOP{}\n\001ASDFGHJKL:\"~\001|ZXCVBNM<>?\001*\001 \001\001\001\001\001\001\001\001\001\001\001\001\001789-456+1230.\002\002\002\001\001\002\002\002\002\002\002\002\002\002\002\002\002\002\002\002\002\002\002\002\002\002\002\002\002\002\002\002\002\002\002\002\002\002\002\002\002\002\002\002";
 
 //====FUNCTIONS:
-
+// The Keyboard Interrupt Service Routine
 void isr_keyboard()
 {
 	kbdScan = inportb(0x60);
@@ -35,10 +36,10 @@ void isr_keyboard()
 
 	if (kbdScan == 0xFA)	//250					//ACKnowledge
 	{
+		//printf("KBD_ACK 0x%x!\n", ackReason);
 		if (ackReason == 0xED)					//reset LEDs
 		{
-			outportb(0x64, (kbdFlags & 0x07));
+			outportb(0x60, (kbdFlags & 0x07));
-			printf("KBD_ACK!");
 		}
 		ackReason = 0;
 	}
@@ -48,7 +49,7 @@ void isr_keyboard()
 		eoi();
 		return;
 	}
-	if (kbdScan == 225)
+	if (kbdScan == 225)						//2nd-set-extended key
 	{
 		kbdExt2 = 2;
 		eoi();
@@ -170,7 +171,8 @@ void isr_keyboard()
 	}
 
 //====do something with key::
-	if ((kbdScan == 83) & ((kbdFlags & KBD_CTRL) != 0) & ((kbdFlags & KBD_ALT) != 0))
+//	printf("kbdScan == %d\nkbdAscii == %d\nkbdFlags == %d\n", kbdScan, kbdAscii, kbdFlags);
+	if ((kbdScan == 83) && (kbdFlags & KBD_CTRL) && (kbdFlags & KBD_ALT))
 	{
 		printf("Initiating reboot.");
 		restart();
@@ -196,19 +198,19 @@ void isr_keyboard()
 
 	eoi();
 
-//	if (key == 0xFA)							//ACKnowledge
-//		outportb(0x60, 0x3);
 }
 
-inline byte switchCase(byte asciiCode)
+//Switches the case of an ASCII character
+/*inline byte (byte asciiCode)
 {
 	if ((asciiCode >= 'A') & (asciiCode <= 'Z'))
 		return (asciiCode + ('a' - 'A'));
 	if ((asciiCode >= 'a') & (asciiCode <= 'z'))
 		return (asciiCode - ('a' - 'A'));
 	return asciiCode;
-}
+}*/
 
+//Gets a key from the buffer, returns 0 if no keys available, returns immediately
 dword kbdGetKey()
 {
 	if (kbdBufferLen == 0)					//buffer empty
@@ -221,6 +223,7 @@ dword kbdGetKey()
 	return retVal;
 }
 
+//Gets a key from the buffer, if no keys available, waits for one to be entered
 dword kbdWaitKey()
 {
 	for (;;)
@@ -236,10 +239,11 @@ dword kbdWaitKey()
 	return retVal;
 }
 
+//Resets the keyboard LEDs to reflect the current state of the num lock, caps lock, and scroll lock bits
 inline void kbd_resetLEDs()
 {
-	outportb(0x64, 0xED);
+	outportb(0x60, 0xED);
-	//outportb(0x64, (kbdFlags & 0x07));
+	//outportb(0x60, (kbdFlags & 0x07));
 	ackReason = 0xED;
 }
 

lib/arc.bat

@@ -0,0 +1,2 @@
+del hlibc.a
+ar -r hlibc.a *.o

lib/comp.bat

@@ -0,0 +1 @@
+gcc -ffreestanding -fno-builtin -c *.c

lib/compa.bat

@@ -0,0 +1,2 @@
+nasmw -f aout -l io.lst io.asm -o io_a.o
+nasmw -f aout -l misc.lst misc.asm -o misc.o

lib/misc.asm

@@ -0,0 +1,25 @@
+
+
+
+;void memcpy(dword src, dword dest, dword length)
+[global _memcpy]
+_memcpy:
+	push	ebp
+	mov	ebp, esp
+	push	esi
+	push	edi
+	push	ecx
+	mov	esi, [ebp+8]
+	mov	edi, [ebp+12]
+	mov	ecx, [ebp+14]
+
+        rep movsb
+
+	pop	ecx
+	pop	edi
+	pop	esi
+	pop	ebp
+	ret
+
+
+

lib/misc.h

@@ -0,0 +1,8 @@
+
+#ifndef __HMISC_H__
+#define __HMISC_H__ __HMISC_H__
+
+void memcpy(dword src, dword dest, dword length);
+
+#endif
+

link.bat

@@ -0,0 +1 @@
+ld -nodefaultlibs -nostdlib -T link.ld -o kernel.bin -Map .\lst\LDout.doc ks.o kernel.o asmfuncs.o .\lib\hlibc.a

link.ld

@@ -2,7 +2,7 @@ OUTPUT_FORMAT("binary")
 ENTRY(start)
 SECTIONS
 {
-  .text  0x100000 : {
+  .text  0x104000 : {
     code = .; _code = .; __code = .;
     *(.text)
     . = ALIGN(4096);

mm.c

@@ -4,9 +4,15 @@
 // 0x368000 is first available byte (this is right after the kernel @ 1mb and the initrd @ 2mb, 1440kb.
 
 
+//Pointer to the first pageblock in the linked list
 pageblock *first_pageblock = (pageblock *) 0;
+//The total amount of physical memory available (bytes)
 dword	mm_totalmem = 0x100000;				//start counting from 1mb
+//The highest physical address
+dword	mm_highestAddress = 0;
 
+//This function initializes the memory manager's linked list, filling it with the
+// memory areas returned by bios interrupt 0x8E20
 void	mm_init()
 {
 	dword	*memmap_entries = (dword *) 0x9040A;
@@ -17,6 +23,8 @@ void	mm_init()
 		if (maps[a].attributes == 1)		// (1) mem free to OS
 		{
 			mm_totalmem += maps[a].limit.lowdword;
+			if (mm_highestAddress < (maps[a].base.lowdword + maps[a].limit.lowdword))
+				mm_highestAddress = maps[a].base.lowdword + maps[a].limit.lowdword;
 			if  ((maps[a].base.lowdword + maps[a].limit.lowdword) > (FREERAM_START+8192))	//goes past where we start freeram
 			{
 				if (maps[a].base.lowdword < FREERAM_START)
@@ -63,7 +71,7 @@ void	mm_init()
 
 
 
-
+//This function initializes a pageblock to be full of empty pointers
 void	mm_init_pageblockpage(pageblock *pbp)
 {
 	int a;
@@ -80,9 +88,13 @@ void	mm_init_pageblockpage(pageblock *pbp)
 }
 
 
+//This function allocates a certain number of physical pages for a particular process
+//Returns:
+// 0 - no free mem, invalied PID
+// void* - physical address of allocated pages
 void   *mm_palloc(dword numpages, dword proc_pid)
 {
- 	if (proc_pid < KERNEL_PID)
+ 	if (proc_pid < PID_KERNEL)
  		return 0;
 	pageblock *pb = first_pageblock;
 	if (mm_freeentries() < 2)
@@ -116,6 +128,7 @@ void   *mm_palloc(dword numpages, dword proc_pid)
 }
 
 
+//This method returns the number of free pageblock entries at the end of the linked list
 dword	mm_freeentries()
 {
 	pageblock *pb = first_pageblock;
@@ -131,6 +144,10 @@ dword	mm_freeentries()
 }
 
 
+//This method creates a new page used to hold more pageblock entries at the end of the linked list
+//Returns:
+// 0 - no free pages
+// pageblock* - address of pageblock page
 pageblock *mm_new_pageblock_page()  	//as of 09/26/03 this method leaks 4kb main memory per call, unrecoverable
 {
 	pageblock *pb = first_pageblock;
@@ -152,6 +169,11 @@ pageblock *mm_new_pageblock_page()  	//as of 09/26/03 this method leaks 4kb main
 }
 
 
+//This method frees a physical page
+//Returns:
+// 2 - pointer to free was a null pointer
+// 1 - address not found
+// 0 - all went well
 int	mm_pfree(void *ptr)
 {
  	if (ptr == 0)
@@ -173,6 +195,7 @@ int	mm_pfree(void *ptr)
 }
 
 
+//This method returns a pointer to the last pageblock in the linked list
 pageblock *mm_lastpageblockentry()
 {
 	pageblock *pb = first_pageblock;
@@ -185,6 +208,8 @@ pageblock *mm_lastpageblockentry()
 }
 
 
+//This method returns the next available-for-use pageblock entry
+// or 0, if they are all used
 pageblock *mm_nextpageblockentry()
 {
 	pageblock *pb = first_pageblock;
@@ -199,6 +224,7 @@ pageblock *mm_nextpageblockentry()
 }
 
 
+//This method returns the amount of free physical RAM
 dword mm_freemem()
 {
 	dword amount = 0;
@@ -214,6 +240,8 @@ dword mm_freemem()
 }
 
 
+//This method "walks" through the linked list of pageblock entries and
+// combines any two entries that are adjacent and of the same type
 void	mm_coalesce(pageblock *pb)
 {
 	pageblock *pbc = first_pageblock;

mouse.c

@@ -3,6 +3,7 @@
 // Author: Josh Holtrop
 
 
+//This method initializes the ps/2 mouse
 void mouse_init()
 {
 	outportb(0x64, 0x20);		//tell keyboard controller we are going to read keyboard controller command byte
@@ -15,12 +16,15 @@ void mouse_init()
 	outportb(0x64, 0xD4);	//send command to mouse, not kbd
 	outportb(0x60, 0xF4);	//enable data reporting
 	
+	mouse_x = video_mode.XResolution >> 1;
+	mouse_y = video_mode.YResolution >> 1;
+
 	//outportb(0x64, 0xD4);
 	//outportb(0x60, 0xE7);	//scaling 2:1
 }
 
 
-
+//This method is called when a mouse interrupt occurs
 void isr_mouse()
 {
 	byte inb = inportb(0x60);	//read mouse byte
@@ -37,14 +41,22 @@ void isr_mouse()
 		int adjy = (char) mouse_inbuffer[2];
 		mouse_x += adjx;
 		mouse_y -= adjy;						//-= because screen y coordinates are opposite mouse y coordinates
+		if (mouse_x < 0)
+			mouse_x = 0;
+		if (mouse_x >= video_mode.XResolution)
+			mouse_x = video_mode.XResolution - 1;
+		if (mouse_y < 0)
+			mouse_y = 0;
+		if (mouse_y >= video_mode.YResolution)
+			mouse_y = video_mode.YResolution - 1;
 		if (mouse_inbuffer[0] & 0x01)	//left button
 		{
-			video_pset(VXR/2+mouse_x, VYR/2+mouse_y, 0x00FFFFFF);
+			video_pset(mouse_x, mouse_y, 0x00FF8800);
 			printf("X: %d, Y: %d\n", mouse_x, mouse_y);
 		}
 		else
 		{
-			video_pset(VXR/2+mouse_x, VYR/2+mouse_y, 0x00000000);
+			video_pset(mouse_x, mouse_y, 0x00FFFFFF);
 			printf("X: %d, Y: %d\n", mouse_x, mouse_y);
 		}
 	}

mouse.h

@@ -3,8 +3,8 @@
 // Author: Josh Holtrop
 
 
-int mouse_x = 0;
+int mouse_x;
-int mouse_y = 0;
+int mouse_y;
 int mouse_bytesRead = 0;
 byte mouse_inbuffer[16];
 

stage1.asm

@@ -28,12 +28,12 @@ brDrive		DB      0               ; 0024h - Physical drive no.
 		DB      0               ; 0025h - Reserved (FAT32)
 		DB      29H             ; 0026h - Extended boot record sig (FAT32)
 brSerialNum     DD      404418EAH       ; 0027h - Volume serial number
-brLabel         DB      'HOS 0.1.1  '   ; 002Bh - Volume label
+brLabel         DB      'Holtrops OS'   ; 002Bh - Volume label
 brFSID          DB      'FAT12   '      ; 0036h - File System ID
 ;------------------------------------------------------------------------
 
 start:
-	jmp	0:jmphere		;ensure that cs=0 and ip=0x7c...
+	jmp	0:jmphere		;ensure that cs=0 and ip=0x7c00...
 jmphere:
 	;dl=drive number, save it!
 	xor	ax, ax
@@ -88,7 +88,7 @@ unreal:
 	pop	es		;segments back, with 4gb limits!
 	sti
 
-;now lets read in the FAT and root directory so we can search for the kernel file...
+;now lets read in the FAT and root directory so we can search for the stage2 file...
 	mov	ax, 0x0209		;FAT1
 	mov	cx, 0x0002
 	xor	dh, dh

stage2.asm

@@ -30,6 +30,7 @@ loop_name:
 	jmp	found_file		;good file, ds:si points to start of root directory entry
 goon:
 	pop	si
+	add	si, 32
 	pop	cx
 	loop	loop_compare
 

stdfont.h

@@ -0,0 +1,258 @@
+const byte stdfont[] = {
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x80, 0xC0, 0xE0, 0xF0, 0xE0, 0xC0, 0x80, 
+	0x00, 0x08, 0x18, 0x38, 0x78, 0x38, 0x18, 0x08, 
+	0x00, 0x20, 0x70, 0xA8, 0x20, 0xA8, 0x70, 0x20, 
+	0x00, 0xA0, 0xA0, 0xA0, 0xA0, 0x00, 0xA0, 0xA0, 
+	0x00, 0x78, 0xA8, 0xA8, 0x78, 0x28, 0x28, 0x68, 
+	0x00, 0x78, 0x80, 0x70, 0x88, 0x70, 0x08, 0xF0, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xF8, 0xF8, 
+	0x00, 0x20, 0x70, 0xA8, 0x20, 0xA8, 0x70, 0xF8, 
+	0x00, 0x20, 0x70, 0xA8, 0x20, 0x20, 0x20, 0x20, 
+	0x00, 0x20, 0x20, 0x20, 0x20, 0xA8, 0x70, 0x20, 
+	0x00, 0x00, 0x20, 0x10, 0xF8, 0x10, 0x20, 0x00, 
+	0x00, 0x00, 0x20, 0x40, 0xF8, 0x40, 0x20, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x40, 0x00, 0x00, 0x00, 
+	0x00, 0x60, 0x90, 0x60, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x20, 0x70, 0xF8, 0xF8, 0x00, 0x00, 
+	0x00, 0x00, 0xF8, 0xF8, 0x70, 0x20, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x20, 0x20, 0x20, 0x20, 0x00, 0x20, 0x20, 
+	0x00, 0x50, 0x50, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x50, 0xF8, 0x50, 0x50, 0x50, 0xF8, 0x50, 
+	0x00, 0x20, 0x78, 0xA0, 0x70, 0x28, 0xF0, 0x20, 
+	0x00, 0x00, 0x08, 0x90, 0x20, 0x48, 0x80, 0x00, 
+	0x00, 0x20, 0x50, 0x50, 0x20, 0x58, 0x90, 0x68, 
+	0x00, 0x40, 0x40, 0x80, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x20, 0x40, 0x40, 0x40, 0x40, 0x40, 0x20, 
+	0x00, 0x40, 0x20, 0x20, 0x20, 0x20, 0x20, 0x40, 
+	0x00, 0x00, 0xA8, 0x70, 0xF8, 0x70, 0xA8, 0x00, 
+	0x00, 0x00, 0x20, 0x20, 0xF8, 0x20, 0x20, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x20, 0x40, 
+	0x00, 0x00, 0x00, 0x00, 0xF0, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x60, 0x60, 
+	0x00, 0x00, 0x08, 0x10, 0x20, 0x40, 0x80, 0x00, 
+	0x00, 0x70, 0x88, 0x88, 0x88, 0x88, 0x88, 0x70, 
+	0x00, 0x20, 0x60, 0xA0, 0x20, 0x20, 0x20, 0x20, 
+	0x00, 0x70, 0x88, 0x08, 0x10, 0x20, 0x40, 0xF8, 
+	0x00, 0x70, 0x88, 0x08, 0x10, 0x08, 0x88, 0x70, 
+	0x00, 0x30, 0x50, 0x90, 0x90, 0xF8, 0x10, 0x10, 
+	0x00, 0xF8, 0x80, 0x80, 0xF8, 0x08, 0x88, 0x70, 
+	0x00, 0x38, 0x40, 0x80, 0xF0, 0x88, 0x88, 0x70, 
+	0x00, 0xF8, 0x08, 0x10, 0x20, 0x40, 0x40, 0x40, 
+	0x00, 0x70, 0x88, 0x88, 0x70, 0x88, 0x88, 0x70, 
+	0x00, 0x70, 0x88, 0x88, 0x78, 0x08, 0x10, 0x60, 
+	0x00, 0x00, 0x00, 0x60, 0x00, 0x00, 0x60, 0x00, 
+	0x00, 0x00, 0x00, 0x60, 0x00, 0x00, 0x60, 0x40, 
+	0x00, 0x10, 0x20, 0x40, 0x80, 0x40, 0x20, 0x10, 
+	0x00, 0x00, 0x00, 0xF0, 0x00, 0xF0, 0x00, 0x00, 
+	0x00, 0x80, 0x40, 0x20, 0x10, 0x20, 0x40, 0x80, 
+	0x00, 0x70, 0x88, 0x08, 0x10, 0x20, 0x00, 0x20, 
+	0x00, 0x70, 0x88, 0x88, 0xB8, 0xB0, 0x80, 0x78, 
+	0x00, 0x70, 0x88, 0x88, 0xF8, 0x88, 0x88, 0x88, 
+	0x00, 0xF0, 0x88, 0x88, 0xF0, 0x88, 0x88, 0xF0, 
+	0x00, 0x70, 0x88, 0x80, 0x80, 0x80, 0x88, 0x70, 
+	0x00, 0xF0, 0x88, 0x88, 0x88, 0x88, 0x88, 0xF0, 
+	0x00, 0xF8, 0x80, 0x80, 0xF0, 0x80, 0x80, 0xF8, 
+	0x00, 0xF8, 0x80, 0x80, 0xF0, 0x80, 0x80, 0x80, 
+	0x00, 0x70, 0x88, 0x80, 0xB8, 0x88, 0x88, 0x70, 
+	0x00, 0x88, 0x88, 0x88, 0xF8, 0x88, 0x88, 0x88, 
+	0x00, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 
+	0x00, 0x10, 0x10, 0x10, 0x10, 0x10, 0x90, 0x60, 
+	0x00, 0x88, 0x90, 0xA0, 0xC0, 0xA0, 0x90, 0x88, 
+	0x00, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0xF8, 
+	0x00, 0x88, 0xD8, 0xA8, 0x88, 0x88, 0x88, 0x88, 
+	0x00, 0x88, 0xC8, 0xE8, 0xB8, 0x98, 0x88, 0x88, 
+	0x00, 0x70, 0x88, 0x88, 0x88, 0x88, 0x88, 0x70, 
+	0x00, 0xF0, 0x88, 0x88, 0xF0, 0x80, 0x80, 0x80, 
+	0x00, 0x70, 0x88, 0x88, 0x88, 0xA8, 0x98, 0x70, 
+	0x00, 0xF0, 0x88, 0x88, 0xF0, 0xA0, 0x90, 0x88, 
+	0x00, 0x70, 0x88, 0x80, 0x70, 0x08, 0x88, 0x70, 
+	0x00, 0xF8, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 
+	0x00, 0x88, 0x88, 0x88, 0x88, 0x88, 0x88, 0x70, 
+	0x00, 0x88, 0x88, 0x88, 0x88, 0x88, 0x50, 0x20, 
+	0x00, 0x88, 0x88, 0x88, 0x88, 0x88, 0xA8, 0x50, 
+	0x00, 0x88, 0x50, 0x20, 0x20, 0x50, 0x88, 0x88, 
+	0x00, 0x88, 0x88, 0x50, 0x20, 0x20, 0x20, 0x20, 
+	0x00, 0xF8, 0x08, 0x10, 0x20, 0x40, 0x80, 0xF8, 
+	0x00, 0x70, 0x40, 0x40, 0x40, 0x40, 0x40, 0x70, 
+	0x00, 0x80, 0xC0, 0x60, 0x30, 0x18, 0x08, 0x00, 
+	0x00, 0xE0, 0x20, 0x20, 0x20, 0x20, 0x20, 0xE0, 
+	0x00, 0x20, 0x50, 0x88, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xF8, 
+	0x00, 0x60, 0x20, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x70, 0x08, 0x78, 0x88, 0x78, 
+	0x00, 0x80, 0x80, 0xF0, 0x88, 0x88, 0x88, 0xF0, 
+	0x00, 0x00, 0x00, 0x70, 0x88, 0x80, 0x88, 0x70, 
+	0x00, 0x08, 0x08, 0x78, 0x88, 0x88, 0x88, 0x78, 
+	0x00, 0x00, 0x00, 0x70, 0x88, 0xF8, 0x80, 0x78, 
+	0x00, 0x30, 0x40, 0x40, 0xE0, 0x40, 0x40, 0x40, 
+	0x00, 0x00, 0x00, 0x78, 0x88, 0x78, 0x08, 0x70, 
+	0x00, 0x80, 0x80, 0xF0, 0x88, 0x88, 0x88, 0x88, 
+	0x00, 0x20, 0x00, 0x20, 0x20, 0x20, 0x20, 0x20, 
+	0x00, 0x10, 0x00, 0x10, 0x10, 0x10, 0x90, 0x60, 
+	0x00, 0x80, 0x80, 0x90, 0xA0, 0xC0, 0xA0, 0x90, 
+	0x00, 0xC0, 0x40, 0x40, 0x40, 0x40, 0x40, 0xE0, 
+	0x00, 0x00, 0x00, 0xD0, 0xA8, 0xA8, 0xA8, 0xA8, 
+	0x00, 0x00, 0x00, 0xF0, 0x88, 0x88, 0x88, 0x88, 
+	0x00, 0x00, 0x00, 0x70, 0x88, 0x88, 0x88, 0x70, 
+	0x00, 0x00, 0x00, 0xF0, 0x88, 0xF0, 0x80, 0x80, 
+	0x00, 0x00, 0x00, 0x78, 0x88, 0x78, 0x08, 0x38, 
+	0x00, 0x00, 0x00, 0x70, 0x48, 0x40, 0x40, 0x40, 
+	0x00, 0x00, 0x00, 0x78, 0x80, 0x70, 0x08, 0xF0, 
+	0x00, 0x40, 0x40, 0xE0, 0x40, 0x40, 0x40, 0x20, 
+	0x00, 0x00, 0x00, 0x88, 0x88, 0x88, 0x88, 0x78, 
+	0x00, 0x00, 0x00, 0x88, 0x88, 0x88, 0x50, 0x20, 
+	0x00, 0x00, 0x00, 0x88, 0x88, 0x88, 0xA8, 0x50, 
+	0x00, 0x00, 0x00, 0x88, 0x50, 0x20, 0x50, 0x88, 
+	0x00, 0x00, 0x00, 0x88, 0x88, 0x78, 0x08, 0xF0, 
+	0x00, 0x00, 0x00, 0xF8, 0x10, 0x20, 0x40, 0xF8, 
+	0x00, 0x30, 0x40, 0x40, 0x80, 0x40, 0x40, 0x30, 
+	0x00, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 
+	0x00, 0xC0, 0x20, 0x20, 0x10, 0x20, 0x20, 0xC0, 
+	0x00, 0x00, 0x68, 0x90, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x70, 0x88, 0x88, 0xF8, 0x88, 0x88, 0x88, 
+	0x00, 0xF8, 0x88, 0x80, 0xF0, 0x88, 0x88, 0xF0, 
+	0x00, 0xF0, 0x88, 0x88, 0xF0, 0x88, 0x88, 0xF0, 
+	0x00, 0xF8, 0x48, 0x40, 0x40, 0x40, 0x40, 0xE0, 
+	0x00, 0xF0, 0x50, 0x50, 0x50, 0x50, 0x78, 0x88, 
+	0x00, 0xF8, 0x80, 0x80, 0xF0, 0x80, 0x80, 0xF8, 
+	0x00, 0xA8, 0xA8, 0x70, 0x20, 0x70, 0xA8, 0xA8, 
+	0x00, 0x70, 0x88, 0x08, 0x30, 0x08, 0x88, 0x70, 
+	0x00, 0x88, 0x98, 0xA8, 0xA8, 0xA8, 0xC8, 0x88, 
+	0x00, 0xA8, 0xC8, 0x98, 0xA8, 0xA8, 0xC8, 0x88, 
+	0x00, 0x88, 0x90, 0xA0, 0xC0, 0xA0, 0x90, 0x88, 
+	0x00, 0xF8, 0x50, 0x50, 0x50, 0x50, 0x50, 0x90, 
+	0x00, 0x88, 0xD8, 0xA8, 0x88, 0x88, 0x88, 0x88, 
+	0x00, 0x88, 0x88, 0x88, 0xF8, 0x88, 0x88, 0x88, 
+	0x00, 0x70, 0x88, 0x88, 0x88, 0x88, 0x88, 0x70, 
+	0x00, 0xF8, 0x88, 0x88, 0x88, 0x88, 0x88, 0x88, 
+	0x00, 0xF0, 0x88, 0x88, 0xF0, 0x80, 0x80, 0x80, 
+	0x00, 0x70, 0x88, 0x80, 0x80, 0x80, 0x88, 0x70, 
+	0x00, 0xF8, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 
+	0x00, 0x88, 0x88, 0x88, 0x50, 0x20, 0x40, 0x80, 
+	0x00, 0x70, 0x20, 0xF8, 0xA8, 0xF8, 0x20, 0x70, 
+	0x00, 0x88, 0x88, 0x50, 0x20, 0x50, 0x88, 0x88, 
+	0x00, 0x88, 0x88, 0x88, 0x88, 0x88, 0xF8, 0x08, 
+	0x00, 0x88, 0x88, 0x88, 0xF8, 0x08, 0x08, 0x38, 
+	0x00, 0xA8, 0xA8, 0xA8, 0xA8, 0xA8, 0xA8, 0xF8, 
+	0x00, 0xA8, 0xA8, 0xA8, 0xA8, 0xA8, 0xF8, 0x08, 
+	0x00, 0xC0, 0x40, 0x40, 0x78, 0x48, 0x48, 0x78, 
+	0x00, 0x88, 0x88, 0xC8, 0xA8, 0xA8, 0xA8, 0xE8, 
+	0x00, 0x80, 0x80, 0xF0, 0x88, 0x88, 0x88, 0xF0, 
+	0x00, 0xF0, 0x88, 0x08, 0x78, 0x08, 0x88, 0xF0, 
+	0x00, 0x90, 0xA8, 0xA8, 0xE8, 0xA8, 0xA8, 0x90, 
+	0x00, 0x78, 0x88, 0x88, 0x78, 0x28, 0x48, 0x88, 
+	0x00, 0x00, 0x70, 0x08, 0x78, 0x88, 0x88, 0x78, 
+	0x00, 0x00, 0xF8, 0x80, 0xF0, 0x88, 0x88, 0xF0, 
+	0x00, 0x00, 0xF0, 0x88, 0xF0, 0x88, 0x88, 0xF0, 
+	0x00, 0x00, 0xF8, 0x48, 0x48, 0x40, 0x40, 0xE0, 
+	0x00, 0x00, 0x78, 0x50, 0x50, 0x50, 0x70, 0x88, 
+	0x00, 0x00, 0x70, 0x88, 0xF8, 0x80, 0x88, 0x70, 
+	0x00, 0x00, 0xA8, 0x70, 0x20, 0x70, 0xA8, 0xA8, 
+	0x00, 0x00, 0x00, 0xF0, 0x88, 0x30, 0x88, 0x70, 
+	0x00, 0x00, 0x88, 0x98, 0xA8, 0xC8, 0x88, 0x88, 
+	0x00, 0x50, 0x20, 0x88, 0x98, 0xA8, 0xC8, 0x88, 
+	0x00, 0x00, 0x88, 0x90, 0xA0, 0xE0, 0x90, 0x88, 
+	0x00, 0x00, 0xF8, 0x48, 0x48, 0x48, 0x48, 0xC8, 
+	0x00, 0x00, 0x88, 0xD8, 0xA8, 0x88, 0x88, 0x88, 
+	0x00, 0x00, 0x88, 0x88, 0xF8, 0x88, 0x88, 0x88, 
+	0x00, 0x00, 0x70, 0x88, 0x88, 0x88, 0x88, 0x70, 
+	0x00, 0x00, 0xF8, 0x88, 0x88, 0x88, 0x88, 0x88, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x70, 0x50, 0x70, 0x08, 0x78, 0x88, 0x78, 
+	0x00, 0x88, 0x00, 0x70, 0x08, 0x78, 0x88, 0x78, 
+	0x00, 0x88, 0x00, 0x70, 0x88, 0x88, 0x88, 0x70, 
+	0x00, 0x88, 0x00, 0x88, 0x88, 0x88, 0x88, 0x78, 
+	0x00, 0x90, 0x00, 0xF0, 0x80, 0xE0, 0x80, 0xF0, 
+	0x00, 0x00, 0x70, 0x48, 0x70, 0x48, 0x48, 0xF0, 
+	0x00, 0x88, 0x00, 0x20, 0x20, 0x20, 0x20, 0x20, 
+	0x00, 0x88, 0x00, 0x70, 0x88, 0xF8, 0x80, 0x78, 
+	0x00, 0x70, 0x50, 0x70, 0x88, 0xF8, 0x88, 0x88, 
+	0x00, 0x88, 0x70, 0x88, 0x88, 0xF8, 0x88, 0x88, 
+	0x00, 0x88, 0x70, 0x88, 0x88, 0x88, 0x88, 0x70, 
+	0x00, 0x88, 0x00, 0x88, 0x88, 0x88, 0x88, 0x78, 
+	0x00, 0x88, 0xF8, 0x80, 0xE0, 0x80, 0x80, 0xF8, 
+	0x00, 0x40, 0x20, 0x70, 0x88, 0xF8, 0x80, 0x78, 
+	0x00, 0x10, 0x20, 0x70, 0x88, 0xF8, 0x80, 0x78, 
+	0x00, 0x20, 0x50, 0x70, 0x88, 0xF8, 0x80, 0x78, 
+	0x00, 0x40, 0x20, 0x70, 0x08, 0x78, 0x88, 0x78, 
+	0x00, 0x20, 0x50, 0x00, 0x20, 0x20, 0x20, 0x20, 
+	0x00, 0x20, 0x10, 0x88, 0x88, 0x88, 0x88, 0x78, 
+	0x00, 0x00, 0x00, 0x70, 0x80, 0x80, 0x70, 0x20, 
+	0x00, 0x70, 0x88, 0x40, 0xF0, 0x40, 0x40, 0xF8, 
+	0x00, 0x88, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x88, 0x88, 0x88, 0xF0, 0x80, 0x80, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0xF0, 0x88, 0x88, 0xF0, 0x80, 0x80, 
+	0x00, 0x00, 0x70, 0x88, 0x80, 0x80, 0x88, 0x70,
+	0x00, 0x00, 0xF8, 0x20, 0x20, 0x20, 0x20, 0x20, 
+	0x00, 0x00, 0x88, 0x88, 0x50, 0x20, 0x40, 0x80, 
+	0x00, 0x00, 0x70, 0x20, 0xF8, 0xF8, 0x20, 0x70, 
+	0x00, 0x00, 0x88, 0x50, 0x20, 0x50, 0x88, 0x88, 
+	0x00, 0x00, 0x88, 0x88, 0x88, 0x88, 0xF8, 0x08, 
+	0x00, 0x00, 0x88, 0x88, 0x88, 0xF8, 0x08, 0x38, 
+	0x00, 0x00, 0xA8, 0xA8, 0xA8, 0xA8, 0xA8, 0xF8, 
+	0x00, 0x00, 0xA8, 0xA8, 0xA8, 0xA8, 0xF8, 0x08, 
+	0x00, 0x00, 0xC0, 0x40, 0x70, 0x48, 0x48, 0x70, 
+	0x00, 0x00, 0x88, 0x88, 0xC8, 0xA8, 0xA8, 0xE8, 
+	0x00, 0x00, 0x80, 0x80, 0xF0, 0x88, 0x88, 0xF0, 
+	0x00, 0x00, 0x70, 0x88, 0x38, 0x08, 0x88, 0x70, 
+	0x00, 0x00, 0x90, 0xA8, 0xA8, 0xE8, 0xA8, 0x90, 
+	0x00, 0x00, 0x38, 0x48, 0x48, 0x38, 0x28, 0x48, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00	};
+

tetris.c

@@ -1,7 +0,0 @@
-
-// tetris.x
-// Author: Josh Holtrop
-// Date: 09/30/03
-
-
-

video.c

@@ -1,7 +1,9 @@
 //video.c
 // 08/13/03 Josh Holtrop
+// Modified: 11/12/03
 
 
+//Initialized the video mode information block video_mode and allocated double-buffer memory for graphics display
 void video_init(ModeInfoBlock *mib)
 {
 	video_mode = *mib;
@@ -10,137 +12,131 @@ void video_init(ModeInfoBlock *mib)
 	{
 	case 16:
 		vid_ptr16 = (word *) video_mode.PhysBasePtr;
+		video_psetp = &video_psetp16;
 		break;
 	case 24:
 		vid_ptr24 = (byte *) video_mode.PhysBasePtr;
+		video_psetp = &video_psetp24;
 		break;
 	case 32:
+		video_psetp = &video_psetp32;
 		vid_ptr32 = (dword *) video_mode.PhysBasePtr;
 	}
-
-	dword tot = ((video_mode.XResolution) * (video_mode.YResolution));
-	int a;
-	for (a = 0; a < tot; a++)
-	{
-		if (a < (tot / 4))
-			video_psetp(a, 0x00FF0000);
-				else if (a < (tot / 2))
-			video_psetp(a, 0x0000FF00);
-		else if (a < ((tot * 3) / 4))
-			video_psetp(a, 0x000000FF);
-		else
-			video_psetp(a, 0x00FFFFFF);		
-	}
 }
 
+//Renders a character using stdfont[] as a bitmask
+void video_renderChar(int x, int y, int character, dword color)
+{
+	int charpos = (character & 0xFF) * 8;
+	int row;
+	int col;
+	for (row = 0; row < 8; row++)
+	{
+		for (col = 0; col < 5; col++)
+		{
+			if ((stdfont[charpos+row] >> (col+3)) & 0x01)
+				video_pset(x+(5-col), y+row, color);
+		}
+	}
+}
+
+//Draws a horizontal line
 void video_horiz(int y, int x1, int x2, dword color)
 {
-	checkBoundsy(y);
-	checkBoundsx(x1);
-	checkBoundsx(x2);
 	if (x1 > x2)
 	{
 		int tmp = x2;
 		x2 = x1;
-		x1 = tmp;
+		x1 = tmp;		//x2 >= x1 now
 	}
+	if (x2 < 0)
+		return;
+	if (x1 > video_mode.XResolution)
+		return;
+	if (x1 < 0)
+		x1 = 0;
+	if (x2 > video_mode.XResolution)
+		x2 = video_mode.XResolution;
 	int pixel = y*video_mode.XResolution+x1;
-	int a;
+	for (; x1 <= x2; x1++)
-	for (a = 0; a <= (x2-x1); a++)
 	{
-		video_psetp(pixel, color);
+		video_psetp(pixel++, color);
-		pixel++;
 	}
 }
 
+//Draws a vertical line
 void video_vert(int x, int y1, int y2, dword color)
 {
-	checkBoundsx(x);
-	checkBoundsy(y1);
-	checkBoundsy(y2);
 	if (y1 > y2)
 	{
 		int tmp = y2;
 		y2 = y1;
-		y1 = tmp;
+		y1 = tmp;		//y2 >= y1 now
 	}
+	if (y2 < 0)
+		return;
+	if (y1 > video_mode.YResolution)
+		return;
+	if (y1 < 0)
+		y1 = 0;
+	if (y2 > video_mode.YResolution)
+		y2 = video_mode.YResolution;
 	int pixel = y1*video_mode.XResolution+x;
-	int a;
+	for (; y1 <= y2; y1++)
-	for (a = 0; a <= (y2-y1); a++)
 	{
 		video_psetp(pixel, color);
 		pixel+=video_mode.XResolution;
 	}
 }
 
+//Draws a rectangle
 void video_rect(int x1, int y1, int x2, int y2, dword color)
 {
-	checkBoundsx(x1);
-	checkBoundsx(x2);
-	checkBoundsy(y1);
-	checkBoundsy(y2);
-	if (x2 < x1)
-	{
-		int tmp = x2;
-		x2 = x1;
-		x1 = tmp;
-	}
-	if (y2 < y1)
-	{
-		int tmp = y2;
-		y2 = y1;
-		y1 = tmp;
-	}
 	video_horiz(y1, x1, x2, color);
 	video_horiz(y2, x1, x2, color);
 	video_vert(x1, y1, y2, color);
 	video_vert(x2, y1, y2, color);
 }
 
+//Draws a filled rectangle
 void video_rectf(int x1, int y1, int x2, int y2, dword color)
 {
-	checkBoundsx(x1);
-	checkBoundsx(x2);
-	checkBoundsy(y1);
-	checkBoundsy(y2);
-	if (x2 < x1)
-	{
-		int tmp = x2;
-		x2 = x1;
-		x1 = tmp;
-	}
 	if (y2 < y1)
 	{
 		int tmp = y2;
 		y2 = y1;
 		y1 = tmp;
 	}
-	int a;
+	for (; y1 <= y2; y1++)
-	for (a = 0; a <= (y2-y1); a++)
+		video_horiz(y1, x1, x2, color);
-		video_horiz(y1+a, x1, x2, color);
 }
 
+//Draws a single pixel
 inline void video_pset(int x, int y, dword color)
 {
+	if ((x < 0) || (x > video_mode.XResolution) || (y < 0) || (y > video_mode.YResolution))
+		return;
 	video_psetp(y*video_mode.XResolution+x, color);
 }
 
-void video_psetp(int pixel, dword color)
+//Draws a pixel at the specified pixel position
+void video_psetp16(int pixel, dword color)
 {
-	switch(video_mode.BitsPerPixel)
-	{
-	case 16:
 	vid_ptr16[pixel] = ((color&0xFF)>>3) | ((((color>>8)&0xFF)>>2)<<5) | ((((color>>16)&0xFF)>>3)<<11);
-		//vid_ptr16[pixel] = ((color&0xFF)>>3) | ((((color>>8)&0xFF)>>3)<<5) | ((((color>>16)&0xFF)>>3)<<10);
+}
-		break;
+
-	case 24:
+//Draws a pixel at the specified pixel position
+void video_psetp24(int pixel, dword color)
+{
 	vid_ptr24[pixel*3] = color & 0xFF;
 	vid_ptr24[pixel*3+1] = (color>>8) & 0xFF;
 	vid_ptr24[pixel*3+2] = (color>>16) & 0xFF;
-		break;
+}
-	case 32:
+
+//Draws a pixel at the specified pixel position
+void video_psetp32(int pixel, dword color)
+{
 	vid_ptr32[pixel] = color;
-	}
 }
 
 

video.h

@@ -1,6 +1,6 @@
 //video.h
 // 08/18/03 Josh Holtrop
-
+// Modified: 11/12/03
 
 void video_init();
 void video_horiz(int y, int x1, int x2, dword color);
@@ -8,11 +8,10 @@ void video_vert(int x, int y1, int y2, dword color);
 void video_rect(int x1, int y1, int x2, int y2, dword color);
 void video_rectf(int x1, int y1, int x2, int y2, dword color);
 inline void video_pset(int x, int y, dword color);
-void video_psetp(int pixel, dword color);
+void video_psetp16(int pixel, dword color);
-
+void video_psetp24(int pixel, dword color);
-
+void video_psetp32(int pixel, dword color);
-#define checkBoundsx(x) (x<0 ? x=0 : (x>=video_mode.XResolution ? x=video_mode.XResolution-1 : 0))
+void video_renderChar(int x, int y, int character, dword color);
-#define checkBoundsy(x) (x<0 ? x=0 : (x>=video_mode.YResolution ? x=video_mode.YResolution-1 : 0))
 
 typedef struct{
 	word	ModeAttributes;
@@ -57,7 +56,7 @@ ModeInfoBlock	video_mode;
 byte	*vid_ptr24;
 word	*vid_ptr16;
 dword	*vid_ptr32;
-
+void (*video_psetp)(int, dword);	//function pointer to set a pixel
 
 
 

vmm.c

@@ -3,6 +3,160 @@
 // Author: Josh Holtrop
 // Date: 09/30/03
 
+PageDirectory	*vmm_PDBR = 0;
+dword	vmm_first_virtual_address = 0;
+
+
+void	vmm_init()
+{
+	if (!(vmm_PDBR = mm_palloc(1, PID_KERNEL)))
+	{
+		printf("ERROR! COULD NOT ALLOCATE PAGE FOR INITIAL PAGE DIRECTORY!!\n");
+		halt();
+	}
+	vmm_init_pagetable((dword)vmm_PDBR);
+
+	if (mm_totalmem % 4096)
+		vmm_first_virtual_address = mm_totalmem + (4096 - (mm_totalmem % 4096));
+	else
+		vmm_first_virtual_address = mm_totalmem;
+
+	if (vmm_mapn(0, 0, 0x03, mm_totalmem/4096+1))
+	{
+		printf("Could not page in all physical RAM!\n");
+		halt();
+	}
+	//we also need to map in the video framebuffer memory:
+	if (video_mode.PhysBasePtr > 0 && video_mode.BitsPerPixel > 0)
+	{
+		if (vmm_mapn(video_mode.PhysBasePtr, video_mode.PhysBasePtr, 0x03, ((video_mode.BitsPerPixel>>3) * video_mode.XResolution * video_mode.YResolution)/4096+1))
+		{
+			printf("Could not page in video memory at 0x%x!\n", video_mode.PhysBasePtr);
+			halt();
+		}
+	}
+}
+
+
+void	vmm_enable_paging()
+{
+	write_cr3((dword)vmm_PDBR);
+	write_cr0(0x80000000|read_cr0());
+}
+
+
+int	vmm_map1(dword virtual, dword physical, dword flags)
+{
+	if (virtual & 0x00000FFF)
+		return 1;			// ERROR 1: address not page-aligned
+	if (physical & 0x00000FFF)
+		return 1;			// ERROR 1: address not page-aligned
+	int pde = (virtual & 0xFFC00000) >> 22;
+	int pte = (virtual & 0x003FF000) >> 12;
+	if (!(vmm_PDBR->pageTables[pde] & 0x01))
+	{
+		vmm_PDBR->pageTables[pde] = (dword)mm_palloc(1, PID_KERNEL) | 0x7;	//user, r/w, present
+		vmm_init_pagetable(vmm_PDBR->pageTables[pde] & 0xFFFFF000);
+		if (vmm_PDBR->pageTables[pde] == 0x07)
+			return 2;		// ERROR 2: page table could not be created
+	}
+	PageTable *ptp = (PageTable *)(vmm_PDBR->pageTables[pde] & 0xFFFFF000);
+	if (ptp->page[pte] & 0x01)
+		return 3;			// ERROR 3: page table entry already exists
+	ptp->page[pte] = physical | flags;
+	//invlpg();
+	return 0;
+}
+
+
+int	vmm_mapn(dword virtual, dword physical, dword flags, dword n)
+{
+	int mapped;
+	int result = 0;
+	dword va = virtual;
+	dword pa = physical;
+	for (mapped = 0; mapped < n; mapped++)
+	{
+		if (result = vmm_map1(va, pa, flags))
+		{
+			if (mapped > 0)
+				vmm_unmapn(virtual, mapped);
+			return result;
+		}
+		va += 4096;
+		pa += 4096;
+	}
+	//invlpg();
+	return 0;
+}
+
+int	vmm_unmap1(dword virtual)
+{
+	if (virtual & 0x00000FFF)
+		return 1;		// ERROR 1: address not page-aligned
+	int pde = (virtual & 0xFFC00000) >> 22;
+	int pte = (virtual & 0x003FF000) >> 12;
+	if (!(vmm_PDBR->pageTables[pde] & 0x01))
+		return 2;		// ERROR 2: page table not present
+	PageTable *ptp = (PageTable *)(vmm_PDBR->pageTables[pde] & 0xFFFFF000);
+	ptp->page[pte] = 0;
+	//invlpg();
+	return 0;
+}
+
+
+int	vmm_unmapn(dword virtual, dword n)
+{
+	int reslt;
+	int i;
+	for (i = 0; i < n; i++)
+	{
+		if (reslt = vmm_unmap1(virtual))
+			return reslt;
+		virtual += 4096;
+	}
+	vmm_walkPageTables();
+	//invlpg();
+	return 0;
+}
+
+
+void	vmm_init_pagetable(dword address)
+{
+	PageTable *ptp = (PageTable *)address;
+	int n;
+	for (n = 0; n < 1024; n++)
+		ptp->page[n] = 0;
+}
+
+
+int	vmm_walkPageTables()
+{
+	int pde;
+	int pte;
+	int used_ptes;
+	PageTable *ptp;
+	for (pde = 0; pde < 1024; pde++)
+	{
+		if (vmm_PDBR->pageTables[pde] & 0x01)
+		{
+			used_ptes = 0;
+			ptp = (PageTable *)(vmm_PDBR->pageTables[pde] & 0xFFFFF000);
+			for (pte = 0; pte < 1024; pte++)
+			{
+				if (ptp->page[pte] & 0x01)	//page table entry present
+					used_ptes++;
+			}
+			if (!(used_ptes))			//no used pte's -- remove page table & page directory entry
+			{
+				mm_pfree(ptp);
+				vmm_PDBR->pageTables[pde] = 0;
+			}
+		}
+	}
+	return 0;
+}
+
 
 void	*malloc(dword bytes)
 {
@@ -12,7 +166,7 @@ void	*malloc(dword bytes)
 
 
 
-int	free(void *ptr);
+int	free(void *ptr)
 {
 
 
@@ -25,3 +179,4 @@ int	free(void *ptr);
 
 
 
+

vmm.h

@@ -4,8 +4,26 @@
 // Date: 09/30/03
 
 
+typedef struct {
+	dword page[1024];
+} PageTable;
+
+typedef struct {
+	dword pageTables[1024];
+} PageDirectory;
+
+
+void	vmm_enable_paging();
+void	vmm_init();
 void   *malloc(dword bytes);
 int	free(void *ptr);
+int	vmm_map1(dword virtual, dword physical, dword flags);
+int	vmm_mapn(dword virtual, dword physical, dword flags, dword n);
+int	vmm_unmap1(dword virtual);
+int	vmm_unmapn(dword virtual, dword n);
+void	vmm_init_pagetable(dword address);
+int	vmm_walkPageTables();
+