add disk read

not implementing disk write yet

README.md

@@ -1,6 +1,10 @@
 # FAT16 bootloader
 	x86 FAT16 bootloader
-	
+
+ # Feature
+* [serial console](https://github.com/Hojun-Cho/bootloader/blob/master/boot/sricon.c)
+* [prompt](https://github.com/Hojun-Cho/bootloader/blob/98601ac381e30d98b4f3f2c20a733beebf9c2ee3/boot/boot.c#L105)
+
 ### How to run
 	1. install image to device
 		install to device
@@ -32,4 +36,4 @@
 		1. set Global Descriptor Table
 		2. enter protected mode
 		2. set Interrupt Descriptor Table
-		3. call boot function 
+		3. call boot function 

boot/Makefile

@@ -5,7 +5,7 @@ PROG = boot
 SRCS = srt0.S gdt.S boot.c
 OBJS = srt0.o gdt.o boot.o
 
-ESRCS = pccon.c sricon.c print.c a20.c time.c
+ESRCS = pccon.c sricon.c print.c fmt.c a20.c time.c mem.c cpu.c alloc.c disk.c
 OBJS += $(ESRCS:.c=.o)
 
 include $(SDIR)/Makefile.inc

boot/alloc.c

@@ -0,0 +1,67 @@
+#include <u.h>
+#include "dat.h"
+#include "fn.h"
+
+// only for booting
+
+typedef struct FreeList FreeList;
+static struct FreeList{
+	uint size;
+	FreeList *next;
+} *freed;
+
+extern char end[];
+static char *top = end;
+
+static void
+putfreed(FreeList *p)
+{
+	p->next = nil;
+	if(freed){
+		p->next = freed;
+		freed = p;
+	}else
+		freed = p;
+}
+
+static FreeList*
+getfreed(uint n)
+{
+	for(FreeList *p=freed,*l=freed; p; p=p->next){
+		if(p->size >= n){
+			l->next = p->next;
+			if(p == freed)
+				freed = nil;
+			return p;
+		}
+		l = p;
+	}
+	return nil;
+}
+
+void*
+alloc(uint n)
+{
+	FreeList *p;
+
+	p = getfreed(n);
+	if(p == nil){
+		p = (FreeList*)top;
+		p->size = n;
+		p->next = nil;
+		memset(p+sizeof(*p), 0, n);
+		top += n + sizeof(*p);
+	}
+if(debug) print("alloc %x %ud\n", &p[1], n);
+	return &p[1];
+}
+
+void
+free(void *src)
+{
+	FreeList *p;
+
+	p = (FreeList*)((char*)src-sizeof(FreeList));
+if(debug) print("free %x %ud\n", src, p->size);
+	putfreed(p);
+}

boot/boot.c

@@ -6,9 +6,11 @@ static void coninit(void);
 static void machdep(void);
 
 void (*probe1[])(void) = {
-	a20up, coninit,
+	a20up, coninit, memprobe,
+	cpuidprobe,
 };
 void (*probe2[])(void) = {
+	diskprobe,
 };
 
 BootProbe probes[] = {
@@ -31,7 +33,11 @@ ConDev contab[CON_END] = {
 		.init = cominit,
 	},
 };
+
 ConDev *con = &contab[0];
+BIOSmmap biosmmap[64];
+uint cnvmem, extmem;
+int debug = BOOT_DEBUG;
 
 static void
 coninit(void)
@@ -92,9 +98,14 @@ done:
 void
 boot(int bootdev)
 {
-	print("\n\n===> Hello world <===\n\tBooted on disk 0x%x\n", bootdev);
-	machdep();	
+	BIOSdisk d = {0,};
 
+	fmtinstall('D', fmtdisk);
+	print("\n===> Hello world <===\n\t"
+		"Booted on disk 0x%x debug:%d\n\t", bootdev, debug);
+	machdep();
+
+	bdiskget(bootdev, &d);
 	for(;;){
 		char buf[8192];
 

boot/cpu.c

@@ -0,0 +1,56 @@
+#include <u.h>
+#include "dat.h"
+#include "fn.h"
+
+#define EFLAG_ID	0x00200000
+#define	CPUID(code, a, b, c, d)				\
+	__asm volatile("cpuid"				\
+	    : "=a" (a), "=b" (b), "=c" (c), "=d" (d)	\
+	    : "a" (code))
+
+void*
+memset(void *dst, int v, int l)
+{
+	char *p = dst;
+	for(int i = 0; i < l; ++i)
+		*p++ = 0;
+	return dst;
+}
+
+void
+cpuidprobe(void)
+{
+	int canuse;
+	union{
+		struct{u32 a,b,d,c;};
+		char arr[16];
+	}r = {0,};	
+
+	__asm volatile("pushfl\n\t"
+		"popl %2\n\t"
+		"xorl %2, %0\n\t"	/* Invert ID sotred in EFLAGS */
+		"pushl %0\n\t"
+		"popfl\n\t"
+		"pushfl\n\t"
+		"popl %0\n\t"
+		"xorl %2, %0\n\t"
+		: "=r" (canuse)
+		: "0" (EFLAG_ID), "r" (0) /* "EFLAGS_ID" same location "canuse" */
+		: "cc");
+	if(canuse != EFLAG_ID){
+		print("cpuid not available\n");
+		return;
+	}
+
+	// print vendor
+	CPUID(0x00, r.a, r.b, r.c, r.d);
+	print("CPU vender: %s\n", r.arr+4);
+	// Is running on Hypervisor?	
+	// But nothing to do...
+	memset(&r, 0,sizeof(r));
+	CPUID(0x01, r.a, r.b, r.c, r.d);
+	if(r.c & (1<<31)){
+		CPUID(1<<30, r.a, r.b, r.c, r.d);
+		print("Running on Hypervisor: %s\n", r.arr+4);
+	}
+}

boot/dat.h

@@ -2,6 +2,13 @@
 // 0x60	Read/Write	Data Port
 // 0x64	Read	Status Register
 // 0x64	Write	Command Register
+#define TABWIDTH 8
+#ifndef BOOT_DEBUG
+#define BOOT_DEBUG 1
+#endif
+
+#define DOSPARTOFF 446
+#define NDOSPART 4
 
 enum{
 	CON_PC,
@@ -36,6 +43,63 @@ struct ConDev{
 	uint dev;
 	uchar pri; // the higher the better
 };
+typedef struct{
+	u64 addr;		/* Beginning of block */
+	u64 size;		/* Size of block */
+	u32 type;		/* Type of block */
+} __attribute__((packed)) BIOSmmap;
+
+// fmt.c
+typedef struct{
+	int ucase;
+	int padch;
+	char *p;
+	char *ep;
+	int f1, f2, f3;
+	va_list ap;
+}Op;
+
+// disk.c
+typedef struct{
+	u8 flag;	/* bootstrap flags */
+	u8 bhd;	/* begin head */
+	u8 bsec;	/* begin sector */
+	u8 bcyl;	/* begin cylinder */
+	u8 type;	/* partition type (see below) */
+	u8 ehd;	/* end head */
+	u8 esec;	/* end sec2r */
+	u8 ecyl;	/* end cylinder */
+	u32 beg;	/* absolute starting sectoff number */
+	u32 size;	/* partition size in sec2rs */
+} __attribute__((packed)) DOSpart;
+
+typedef struct{
+	u8 boot[DOSPARTOFF];
+	DOSpart parts[NDOSPART];
+	u16 sign;
+} __attribute__((packed)) DOSmbr;
+
+typedef struct{
+	int n;
+	u32 ncyl;
+	u32 nhead;
+	u32 nsec;
+	i32 edd;
+	u32 dev ;
+	u32 checksum;
+	u32 flag;
+} __attribute__((packed)) BIOSdisk;
+
+typedef struct{
+
+}Disklabel;
+
+typedef struct{
+	BIOSdisk bdsk;	// bios disk info
+	Disklabel label;
+
+	int bootdev, osdev;
+}Disk;
 
 // gdt.S
 extern volatile struct BIOSreg BIOSreg;
@@ -44,5 +108,8 @@ extern volatile struct BIOSreg BIOSreg;
 extern void (*probe1[])(void);
 extern void (*probe2[])(void);
 extern BootProbe probes[];
+extern BIOSmmap biosmmap[64];
 extern ConDev contab[CON_END];
 extern ConDev *con;
+extern uint cnvmem, extmem;
+extern int debug;

boot/disk.c

@@ -0,0 +1,174 @@
+#include <u.h>
+#include "dat.h"
+#include "fn.h"
+
+#define BDA_DISK 0x0475	// of hard disk drives detected
+#define MAX_DISK_ENTRY 1	// for now
+
+enum{
+	Bread = 0x4200,
+	Bwrite = 0x4300,
+};
+
+// interrupt 41h exension support bitmap
+enum{
+	Eeda	= 0x01,	// Extended disk access funcions 42-44,47,48
+	Erdc	= 0x02,	// removable drive controller functions 45,46,48,49
+	Eedd	= 0x04,	// Enhanced disk drive functions
+};
+
+typedef struct{
+	u8 len;
+	u8 res1;
+	u8 nblk;
+	u8 res2;
+	u16 off;
+	u16 seg;
+	u64 daddr; // starting block
+}EDDcb;
+
+Disk disks[MAX_DISK_ENTRY];
+
+static int
+ireset(int dev)
+{
+	int rv;
+
+	__asm volatile("int $0x33\n\t"
+				"setc %b0"
+				: "=a" (rv)
+				: "0" (0), "d" (dev)
+				: "%ecx", "%cc");	
+	return (rv&0xff) ? -1 : 0;
+}
+
+// Bit(s)  Description     (Table 00271)
+// 0      extended disk access functions (AH=42h-44h,47h,48h) supported
+// 1      removable drive controller functions (AH=45h,46h,48h,49h,INT 15/AH=52h) supported
+// 2      enhanced disk drive (EDD) functions (AH=48h,AH=4Eh) supported.
+// Extended drive parameter table is valid (see #00273,#00278)
+// 3-15   reserved (0)
+static __inline int
+ieddsuport(BIOSdisk *d)
+{
+	int bmap, rv;
+
+	__asm volatile("int $0x33\n\t"
+				"setc %b0"
+				: "=a" (rv), "=c" (bmap)
+				: "0" (0x4100), "b" (0x55aa), "d" (d->n)
+				: "cc");
+	if(rv&0xff || (BIOSreg.bx&0xffff) != 0xaa55)
+		return -1;
+	d->edd = (bmap&0xffff) | ((rv&0xff)<<16);
+	return 0;
+}
+
+static __inline int
+bdiskinfo(BIOSdisk *d)
+{
+	int rv;
+
+	// CL = maximum sector number (bits 5-0)
+	//      high two bits of maximum cylinder number (bits 7-6)
+	__asm volatile("int $0x33\n\t"
+				"setc %b0\n\t"
+				"movzbl %h1, %1\n\t"
+				"movzbl %%cl, %3; andb $0x3f, %b3\n\t"
+				"xchgb %%cl, %%ch; rolb $2, %%ch"
+				: "=a" (rv), "=d" (d->nhead), "=c" (d->ncyl), "=b" (d->nsec)
+				: "0" (0x0800), "1" (d->n)
+				: "cc");
+	return (rv&0xff) == 0 ? 0 : -1;
+}
+
+int
+bdiskget(int dev, BIOSdisk *d)
+{
+	if(ireset(dev)){
+		print("Can't reset disk\n");
+		return -1;
+	}
+	d->n = dev;
+	if(bdiskinfo(d)){
+		print("Can't read disk\n");
+		return -1;
+	}
+	if(ieddsuport(d)){
+		print("edd not supported\n");
+		return -1;
+	}
+	return 0;
+}
+
+static int
+diskrw(uint rw, int dev, u32 daddr, u32 blk, void *buf)
+{
+	int rv;
+	volatile EDDcb cb = {0,};
+
+	cb.len = sizeof(cb);
+	cb.nblk = blk;
+	cb.seg = ((u32)buf>>4 & 0xffff);
+	cb.off = (u32)buf & 0xf;
+	cb.daddr = daddr;
+	if(cb.seg==0 || cb.off==0)
+		return -1;
+	BIOSreg.ds = (u32)&cb >> 4;
+	__asm volatile ("int $0x33\n\t"
+					"setc %b0\n\t"
+					: "=a" (rv)
+					: "0" (rw), "d" (dev), "S" ((int)(&cb)&0xf)
+					: "%ecx", "cc");
+	return rv&0xff? -1 : 0;
+}
+
+static int
+findos(BIOSdisk *bd)
+{
+	DOSmbr mbr = {0,};
+
+	if(diskrw(Bread, bd->n, 0, 1, &mbr)){
+		print("Can't find os disk %d\n", bd->n);
+		return -1;
+	}
+	print("found os disk signature: 0x%x\n", mbr.sign);
+	return 0;
+}
+
+static int
+findlabel(BIOSdisk *b, Disklabel *dl)
+{
+	if(b->n & 0x80){
+		findos(b);
+		return 0;	// for now
+	}
+	print("Can't found disk label:%x \n", b->n);
+	return -1;
+}
+
+void
+diskprobe(void)
+{
+	int n = MIN((int)*(char*)BDA_DISK, MAX_DISK_ENTRY);
+
+	for(int i = 0x80; i < 0x80+n; ++i){
+		if(bdiskget(i, &disks[i].bdsk))
+			return;
+		print("Disnk info: %D\n", disks[i].bdsk);
+		if(findlabel(&disks[i].bdsk, &disks[i].label)){
+
+		}
+	}
+}
+
+int
+fmtdisk(Op *op)
+{
+	dofmt(op, "disk:%x cyl:%d head:%d sec:%d edd:%d");
+	// for skip va_list
+	USED(va_arg(op->ap, u32));
+	USED(va_arg(op->ap, u32));
+	USED(va_arg(op->ap, u32));
+	return 0;
+}

boot/fmt.c

@@ -0,0 +1,304 @@
+#include <u.h>
+#include "dat.h"
+#include "fn.h"
+
+#define MAXCON 30
+#define IDIGIT 30
+
+enum{
+	FLONG = (1<<0),
+	FSHORT = (1<<2),
+	FUNSIGN = (1<<3),
+};
+
+static void put(Op*, int);
+static int noconv(Op*);
+static int cconv(Op*);
+static int dconv(Op*);
+static int hconv(Op*);
+static int lconv(Op*);
+static int sconv(Op*);
+static int uconv(Op*);
+static int xconv(Op*);
+static int Xconv(Op*);
+static int percent(Op*);
+
+static int (*fmtconv[MAXCON])(Op*) = {
+	noconv,
+	cconv, dconv, hconv, lconv,
+	sconv, uconv, xconv, Xconv,
+	percent,
+};
+
+int fmtindex[128] = {
+	['c'] = 1,
+	['d'] = 2,
+	['h'] = 3,
+	['l'] = 4,
+	['s'] = 5,
+	['u'] = 6,
+	['x'] = 7,
+	['X'] = 8,
+	['%'] = 9,
+};
+int convcnt = 11;
+
+int
+strlen(char *s)
+{
+	char *p = s;
+
+	while(*p)
+		++p;
+	return p-s;
+}
+
+int
+fmtinstall(int c, int (*f)(Op*))
+{
+	c &= 0177;
+	if(fmtindex[c] == 0){
+		if(convcnt + 1 >= MAXCON)
+			return -1;
+		fmtindex[c] = convcnt++;
+	}
+	fmtconv[fmtindex[c]] = f;
+	return 0;
+}
+
+char*
+dofmt(Op *op, char *fmt)
+{
+	int sf1, c;
+
+	while(1){
+		c = *fmt++;
+		if(c != '%'){
+			if(c == 0){
+				if(op->p < op->ep)
+					*op->p = 0;
+				return op->p;
+			}
+			put(op, c);
+			continue;
+		}
+		op->f2 = -1;
+		op->f1 = op->f3 = 0;
+		op->padch = sf1 = 0;
+		c = *fmt++;
+		if(c == '-'){
+			sf1 = 1;
+			c = *fmt++;
+		}else if(c == '0' || c == ' '){
+			op->padch = c;
+			c = *fmt++;
+		}
+		while(c >= '0' && c <= '9'){
+			op->f1 = op->f1*10 + c-'0';
+			c = *fmt++;
+		}
+		if(sf1)
+			op->f1 = -op->f1;
+		if(c != '.')
+			goto conv;
+		c = *fmt++;
+		while(c >= '0' && c <= '9'){
+			if(op->f2 < 0)
+				op->f2 = 0;
+			op->f2 = op->f2*10 + c-'0';
+			c = *fmt++;
+		}
+conv:
+		if(c == 0)
+			fmt -= 1;
+		c = (*fmtconv[fmtindex[c&0177]])(op);
+		if(c < 0){
+			op->f3 |= -c;
+			c = *fmt++;
+			goto conv;
+		}
+	}
+}
+
+static void 
+strconv(char *s, Op *op, int f1, int f2)
+{
+	int n, c;
+	char *p;
+
+	n = strlen(s);
+	if(f1 >= 0)
+		while(n < f1){
+			put(op, op->padch);
+			n += 1;
+		}
+	for(p=s; (c = *p++);)
+		if(f2){
+			put(op, c);
+			f2 -= 1;
+		}
+	if(f1 < 0){
+		f1 = -f1;
+		while(n < f1){
+			put(op, ' ');
+			n += 1;
+		}	
+	}
+}
+
+static void 
+numconv(Op *op, int base)
+{
+	char b[IDIGIT];
+	int i,f,n;
+	long v;
+	short h;
+
+	i = IDIGIT-1;
+	f = 0;
+	b[i] = 0;
+	switch(op->f3 & (FLONG|FSHORT|FUNSIGN)){
+	case FLONG:
+		v = va_arg(op->ap, long);
+		break;
+	case FUNSIGN|FLONG:
+		v = va_arg(op->ap, ulong);
+		break;
+	case FSHORT:
+		v = h = va_arg(op->ap, short);
+		break;
+	case FUNSIGN|FSHORT:
+		h = va_arg(op->ap, ushort);
+		v = (ushort)h;
+		break;
+	case FUNSIGN:
+		v = va_arg(op->ap, unsigned);
+		break;
+	default:
+		v = va_arg(op->ap, int);
+		break;
+	}
+	if((op->f3 & FUNSIGN) && v < 0){
+		v = -v;
+		f = 1;
+	}
+	while(--i){
+		n = v % base;
+		n += '0';
+		if(n > '9'){
+			n += 'a' - ('9'+1);
+			if(op->ucase)
+				n += 'A'-'a';
+		}
+		b[i] = n;
+		v = (ulong)v / base;
+		if(i < 2)
+			break;
+		if(op->f2 >= 0 && i >= IDIGIT - op->f2)
+			continue;
+		if(v <= 0)
+			break;
+	}
+	if(f)
+		b[--i] = '-';
+	strconv(b+i, op, op->f1, -1);
+}
+
+static int
+noconv(Op *op)
+{
+	strconv("***ERROR: noconv***", op, 0, -1);
+	return 0;
+}
+
+static int
+cconv(Op *op)
+{
+	char b[2];
+
+	b[0] = va_arg(op->ap, char);
+	b[1] = 0;
+	strconv(b, op, op->f1, -1);
+	return 0;
+}
+
+static int
+dconv(Op *op)
+{
+	numconv(op, 10);
+	return 0;
+}
+
+static int
+hconv(Op *op)
+{
+	return -FSHORT;
+}
+
+static int
+lconv(Op *op)
+{
+	return -FLONG;
+}
+
+static int
+uconv(Op *op)
+{
+	return -FUNSIGN;
+}
+
+static int
+sconv(Op *op)
+{
+	char *p;
+
+	p = va_arg(op->ap, char*);
+	strconv(p?p:"<nil>", op, op->f1, op->f2);
+	return 0; 
+}
+
+static int
+xconv(Op *op)
+{
+	numconv(op, 16);
+	return 0;
+}
+
+static int
+Xconv(Op *op)
+{
+	op->ucase = 1;
+	numconv(op, 16);
+	op->ucase = 0;
+	return 0;
+}
+
+static int
+percent(Op *op)
+{
+	put(op, '%');
+	return 0;
+}
+
+static void
+put(Op *op, int c)
+{
+	static int pos;
+	int opos;
+
+	if(c == 0)
+		return;
+	if(c == '\t'){
+		opos = pos;
+		pos = (opos+TABWIDTH) & (~(TABWIDTH-1));
+		while(opos++ < pos && op->p < op->ep)
+			*op->p++ = ' ';
+		return;
+	}	
+	if(op->p < op->ep){
+		*op->p++ = c;
+		pos++;
+	}
+	if(c == '\n')
+		pos = 0;
+}

boot/fn.h

@@ -1,3 +1,6 @@
+#define MAX(x, y) ((x)>(y)?(x):(y))
+#define MIN(x, y) ((x)<(y)?(x):(y))
+
 // console.c
 void cominit(ConDev *d);
 void pcinit(ConDev *d);
@@ -8,17 +11,44 @@ int comprobe(ConDev *d);
 int comgetc(int dev);
 void computc(int dev, int c);
 
+// fmt.c
+char* dofmt(Op *op, char *fmt);
+int fmtinstall(int c, int (*f)(Op*));
+char *doprint(char *p, char *ep, char *fmt, va_list ap);
+int strlen(char *s);
+
 // print.c
 void putchar(int c);
+void putstr(char *s, int l);
 int getchar(void);
-void print(const char *fmt, ...);
+char* doprint(char *p, char *ep, char *fmt, va_list);
+int print(char *fmt, ...);
+int snprint(char *buf, int len, char *fmt, ...);
 
 // a20.c
 void a20up(void);
 
-// long.c
+// mem.c
+void memprobe(void);
+
+// cpu.c
+void cpuidprobe(void);
+
+// time.c
 long getsecs(void);
 
+// alloc.c
+void *alloc(uint);
+void free(void*);
+
+// disk.c
+int bdiskget(int dev, BIOSdisk *d);
+int fmtdisk(Op *op);
+void diskprobe(void);
+
+// util
+void* memset(void *dst, int v, int l);
+
 static __inline int
 major(int x)
 {

boot/gdt.S

@@ -2,6 +2,16 @@
 
 #include "def.h"
 
+#define	AX 0
+#define	CX 4
+#define	DX 8
+#define	BX 12
+#define	BP 16
+#define	SI 20
+#define	DI 24
+#define	DS 28
+#define	ES 32
+
 #define GEN_LABEL(n)	X##n
 
 // idt entry
@@ -63,22 +73,12 @@
 							\
 	lidt	Idtr;
 
-.text
-.globl	BIOSreg	
-BIOSreg:
-	BIOS_AX: .long 0 
-	BIOS_CX: .long 0 
-	BIOS_DX: .long 0 
-	BIOS_BX: .long 0 
-	BIOS_BP: .long 0 
-	BIOS_SI: .long 0 
-	BIOS_DI: .long 0 
-	BIOS_DS: .long 0 
-	BIOS_ES: .long 0 
-
 .text
 .code32
 .globl	pmode_init	
+.globl	BIOSreg
+BIOSreg:
+	.space 36, 0
 
 //	Table
 //	IDTR offset + 0 : entry 0
@@ -246,11 +246,9 @@ EMUh: // build stack for real mode
 	movb	%al, intno	// save BIOS int vector
 
 // BIOS_regs is  area for saving the contents of registers returned by the BIOS during a BIOS CALL
-	movl	BIOS_ES, %eax
-	movl	$0x00, %eax
+	movl	BIOSreg+ES, %eax
 	mov	%eax, 7f
-	movl	BIOS_DS, %eax
-	movl	$0x00, %eax
+	movl	BIOSreg+DS, %eax
 	mov	%eax, 6f	
 
 	prot2real
@@ -300,12 +298,13 @@ intno = . -1;
 	// movl $Leax, %eax
 	.byte	0xb8
 4:	.long	0x90909090
-	mov	%eax, BIOS_BX
+	movl	%eax, BIOSreg+BX
 
 	// movl $Leax, %eax
 	.byte	0xb8
 3:	.long	0x90909090
-	mov	%eax, BIOS_ES
+	movl	%eax, BIOSreg+ES
+
 
 	// movl $Leax, %eax
 	.byte	0xb8
@@ -318,13 +317,13 @@ intno = . -1;
 	movb	%bh, 0xe*4(%esp)	// restore eflags
 
 	// save register into BIOSREG
-	.code32
-	movl	%eax, BIOS_AX
-	movl	%ecx, BIOS_CX
-	movl	%edx, BIOS_DX
-	movl	%ebp, BIOS_BP
-	movl	%esi, BIOS_SI
-	movl	%edi, BIOS_DI
+	movl	%eax, BIOSreg+AX
+	movl	%ecx, BIOSreg+CX
+	movl	%edx, BIOSreg+DX
+	movl	%ebp, BIOSreg+BP
+	movl	%esi, BIOSreg+SI
+	movl	%edi, BIOSreg+DI
+
 
 	// clear NT(Nested Task Flag: 14) flag in eflag
 	// if 1 : interrupting

boot/mem.c

@@ -0,0 +1,81 @@
+#include <u.h>
+#include "dat.h"
+#include "fn.h"
+
+#define IOMEM_BEGIN 0x0A0000
+#define IOMEM_END   0x100000
+
+enum{
+	MAP_END  = 0x00,
+	MAP_FREE = 0x01,
+	MAP_RES = 0x02,
+	MAP_ACPI_RECLAM = 0x03,
+	MAP_ACPI_NVS = 0x04,
+};
+
+static BIOSmmap*
+int15_E820(BIOSmmap *m)
+{
+	int rc, sig, off = 0;
+	do{
+		BIOSreg.es = ((uint)(m) >> 4);
+		__asm volatile("int $0x35; setc %b1"
+			: "=a" (sig), "=d" (rc), "=b" (off)
+			: "0" (0xE820), "1" (0x534d4150), "b" (off),
+			  "c" (sizeof(*m)), "D" (((uint)m) & 0xf)
+			: "cc", "memory");
+
+		off = BIOSreg.bx;
+		if(rc &0xff || sig !=0x534d4150){
+			break;
+		if(m->type == 0)
+			m->type = MAP_RES;
+		}
+		m++;
+	}while(off);
+	return m;
+}
+
+static void
+dumpmem(BIOSmmap *m)
+{
+	ulong tot = 0;
+
+	for(BIOSmmap *p=m; p->type != MAP_END; ++p){
+		print("MEM % 2ud type %ud size % 10udKB at %08x:%08x\n",
+			p-m, p->type, (uint)(p->size/1024), (uint)(p->addr>>32), (uint)p->addr);
+		if(p->type == MAP_FREE)
+			tot += p->size/1024;
+	}
+	print("RAM low:%udKB high:%udKB\n", cnvmem, extmem);
+	print("Total free memory: %udKB\n", tot);
+}
+
+static int
+isa20done(void)
+{
+	register char *a = (char *)0x100000;
+	register char *b = (char *)0x000000;
+
+	return *a != *b;
+}
+
+void
+memprobe(void)
+{
+	BIOSmmap *m;
+
+	cnvmem = extmem = 0;
+	m = int15_E820(biosmmap);
+	m->type = MAP_END;
+	for(m = biosmmap; m->type != MAP_END; ++m){
+		if(m->type != MAP_FREE || m->size <= 0)
+			continue;
+		if(m->addr < IOMEM_BEGIN)
+			cnvmem = MAX(cnvmem, m->addr + m->size)/1024;
+		if(m->addr >= IOMEM_END)
+			extmem += m->size/1024;
+	}
+	dumpmem(biosmmap);
+	print("A20:%s\n", isa20done() ? "ok" : "no");
+}

boot/print.c

@@ -2,61 +2,49 @@
 #include "dat.h"
 #include "fn.h"
 
-#define TABWIDTH 4
+#define BUFSIZE 1024
 
-static void conputc(int c);
+static void conputc(int);
 static int congetc(void);
-static void doprint(void (*put)(int), const char *fmt, va_list ap);
-static void putint(void (*put)(int), int n, const char *sym, int base);
-static int pos = 0;
 
-void
-print(const char *fmt, ...)
+char*
+doprint(char *p, char *ep, char *fmt, va_list ap)
 {
+	Op op = { .p = p, .ep = ep, .ap = ap };
+	return dofmt(&op, fmt);
+}
+
+int
+print(char *fmt, ...)
+{
+	char buf[BUFSIZE], *p;
 	va_list args;
 
 	va_start(args, fmt);
-	doprint(putchar, fmt, args);
+	p = doprint(buf, buf+sizeof(buf), fmt, args);
 	va_end(args);
+	putstr(buf, p-buf);
+	return p-buf;
 }
 
-static void
-doprint(void (*put)(int), const char *s, va_list ap)
+int
+snprint(char *buf, int len, char *fmt, ...)
 {
-	while(*s){
-		if(*s != '%'){
-			put(*s++);
-			continue;
-		}
-		++s;
-		switch(*s){
-		case 'd':
-			putint(put, va_arg(ap,int), "0123456789", 10);
-			break;
-		case 'x':
-			putint(put, va_arg(ap,int), "0123456789abcdef", 16);
-			break;
-		case 'X':
-			putint(put, va_arg(ap,int), "0123456789ABCDEF", 16);
-			break;
-		case 's':
-			for(char *p=va_arg(ap,char*); *p; ++p)
-				put(*p);
-			break;
-		default:
-			return;
-		}
-		++s;
-	}
-}
+	char *p;
+	va_list args;
 
+	va_start(args, fmt);
+	p = doprint(buf, buf+len, fmt, args);
+	va_end(args);
+	return p-buf;
+}
 
 int
 getchar(void)
 {
 	int c;
 
-	c = congetc();	
+	c = congetc();
 	if(c == '\r')
 		c = '\n';
 	if((c < ' ' && c != '\n') || c == '\177')
@@ -65,6 +53,13 @@ getchar(void)
 	return c;
 }
 
+void
+putstr(char *s, int l)
+{
+	while(l--)
+		putchar(*s++);
+}
+
 void
 putchar(int c)
 {
@@ -72,24 +67,20 @@ putchar(int c)
 	case '\177':
 		conputc('\b');
 		conputc(' ');
+		break;
 	case '\b':
 		conputc('\b');
-		if(pos > 0)
-			--pos;
 		break;
 	case '\t':
-		do{
+		for(int i = 0; i < TABWIDTH; ++i)
 			conputc(' ');
-		}while(++pos % TABWIDTH);
 		break;
 	case '\n':
 	case '\r':
 		conputc(c);
-		pos = 0;
 		break;
 	default:
 		conputc(c);
-		++pos;
 		break;
 	}	
 }
@@ -109,19 +100,3 @@ congetc(void)
 {
 	return con->getc(con->dev);
 }
-
-static void
-putint(void (*put)(int), int n, const char *sym, int base)
-{
-	int i;
-	char buf[16];
-
-	i = 0;
-	do{
-		buf[i++] = n%base;
-		n /= base;
-	}while(n);
-	do{
-		put((int)sym[(int)buf[--i]]);
-	}while(i);
-}