Import backup from 2003-09-26

kernel.c

@@ -24,8 +24,7 @@ void k_init();
 #include "video.c"
 
 dword timer = 0;
-
+dword addresses[256];
-void type();
 
 void k_init()
 {
@@ -35,10 +34,25 @@ void k_init()
 	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);
 	mm_init();
 	enable_ints();
 	console_cls();
-	//printf("Memory available to OS: %d MB (Bytes: %d)\n", mm_totalmem/0x100000, mm_totalmem);
+	printf("Memory available to OS: %d MB (Bytes: %d)\n", mm_totalmem/0x100000, mm_totalmem);
+	int a = 0;
+	for (;;)
+	{
+		addresses[a] = (dword)mm_palloc(256);
+		printf("%x\t", addresses[a]);
+		if (addresses[a++] == 0)
+			break;
+	}
 	dword key = 0;
 	for (;;)
 	{
@@ -51,37 +65,13 @@ void isr(dword num)
 {
 	switch(num)
 	{
-	case 0x20:
+	case 0x20:         		// IRQ0 - timer interrupt
 		timer++;
 		(*(byte *)0xb8000)++;
-		switch(timer)
-		{
-		case 150:
-			video_rectf(VXR*3/11, 0, VXR*4/11, VYR-1, 0x00000088);
-			break;
-		case 200:
-			video_rectf(VXR*7/11, 0, VXR*8/11, VYR-1, 0x00000088);
-			break;
-		case 250:
-			video_rectf(VXR/11, 0, VXR*2/11, VYR*2/5, 0x00000088);
-			break;
-		case 300:
-			video_rectf(VXR/11, VYR*3/5, VXR*2/11, VYR-1, 0x00000088);
-			break;
-		case 350:
-			video_rectf(VXR*5/11, VYR/5, VXR*6/11, VYR*4/5, 0x00000088);
-			break;
-		case 400:
-			video_rectf(VXR*9/11, VYR/5, VXR-1, VYR*2/5, 0x00000088);
-			break;
-		case 450:
-			video_rectf(VXR*8/11, VYR*3/5, VXR*10/11, VYR*4/5, 0x00000088);
-			break;
-		}
 		eoi();
 		break;
-	case 0x21:
+	case 0x21:  			// IRQ1 - keyboard interrupt
-		isr_keyboard();
+		isr_keyboard();    	//isr_keybard() takes care of calling eoi()
 		break;
 	}
 }

mm.c

@@ -5,7 +5,7 @@
 
 
 pageblock *first_pageblock = (pageblock *) 0;
-dword	mm_totalmem = 0x100000;				//assume 1mb
+dword	mm_totalmem = 0x100000;				//start counting from 1mb
 
 void	mm_init()
 {
@@ -26,7 +26,7 @@ void	mm_init()
 				}
 				if (first_pageblock == 0)	//no pageblock page set up yet, so set it up here
 				{
-					first_pageblock = (pageblock *) maps[a].base.lowdword        ;
+					first_pageblock = (pageblock *) maps[a].base.lowdword;
 					maps[a].base.lowdword += 4096;
 					maps[a].limit.lowdword -= 4096;
 					mm_init_pageblockpage(first_pageblock);
@@ -53,9 +53,11 @@ void	mm_init()
 	}
 	if (first_pageblock == 0)
 	{
-		printf("ERROR! NO INITIAL PAGE BLOCK COULD BE CREATED.");
+		printf("ERROR! NO INITIAL PAGE BLOCK CREATED.");
 		asm("cli");
 		asm("hlt");
+		for (;;)
+		;
 	}
 }
 
@@ -64,18 +66,16 @@ void	mm_init()
 
 void	mm_init_pageblockpage(pageblock *pbp)
 {
-	pageblock *pb = pbp;
 	int a;
-	for (a=0; a<512; a++)
+	for (a=0; a<256; a++)       				// 256 pageblock entries * 16 bytes per page block entry = 4096 bytes (1 page of pageblock entries)
 	{
-		pb->base = 0;
+		pbp[a].base = 0;
-		pb->length = 0;
+		pbp[a].length = 0;
-		pb->flags = MM_PB_NP;
+		pbp[a].flags = MM_PB_NP;
-		if (a<511)
+		if (a<255)
-			pb->link = (dword)pb + sizeof(pageblock);
+			pbp[a].link = (dword)(&pbp[a+1]);
 		else
-			pb->link = 0;
+			pbp[a].link = 0;
-		pb++;
 	}
 }
 
@@ -83,8 +83,7 @@ void	mm_init_pageblockpage(pageblock *pbp)
 void   *mm_palloc(dword numpages)
 {
 	pageblock *pb = first_pageblock;
-	dword freeentries = mm_freeentries();
+	if (mm_freeentries() < 2)
-	if (freeentries < 2)
 	{
 		if(mm_new_pageblock_page() == 0)
 			return 0;
@@ -130,7 +129,7 @@ dword	mm_freeentries()
 }
 
 
-pageblock *mm_new_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;
 	for (;;)
@@ -153,11 +152,13 @@ pageblock *mm_new_pageblock_page()
 
 int	mm_pfree(void *ptr)
 {
+ 	if (ptr == 0)
+ 		return 2;
 	pageblock *pb = first_pageblock;
 	dword tofree = (dword) ptr;
 	for (;;)
 	{
-		if ((pb->base == tofree) && (pb->flags == MM_PB_USED))
+		if (pb->base == tofree)		// && (pb->flags == MM_PB_USED))
 		{
 			pb->flags = MM_PB_AVAIL;		//found block, mark available / coalesce it
 			pageblock *pbc = first_pageblock;

mm.h

@@ -11,8 +11,8 @@ typedef struct {
 	dword	base;
 	dword	length;				//in pages
 	dword	flags;
-	dword	link;
+	dword	link;				//leave dword instead of pointer so i dont have to worry about pointer arithmetic
-} __attribute__ ((packed)) pageblock;		//16 byte pageblock entry - 512 entries = 1 page
+} __attribute__ ((packed)) pageblock;		//16 byte pageblock entry - 256 entries = 1 page
 
 
 void	mm_init();
@@ -20,10 +20,10 @@ void	mm_init_pageblockpage(pageblock *pbp);
 void   *mm_palloc(dword numpages);
 int	mm_pfree(void *ptr);
 dword	mm_freeentries();
+dword	mm_freemem();
 pageblock *mm_new_pageblock_page();
 pageblock *mm_lastpageblockentry();
 pageblock *mm_nextpageblockentry();
-dword mm_freemem();
 
 
 #define MM_PB_FLAGMASK 0x03	//00000011