feat(loader): logger print time

LICENSE

@@ -1,6 +1,6 @@
 BSD 3-Clause License
 
-Copyright (c) 2020, d0p1
+Copyright (c) 2024, d0p1
 All rights reserved.
 
 Redistribution and use in source and binary forms, with or without

boot/bootsect/floppy.asm

@@ -93,6 +93,8 @@ _start:
 	xor bx, bx
 	call fat_load_binary
 
+	mov dl, [drive_number]
+
 	jmp 0x0:LOADER_BASE
 
 .error_not_found:

boot/bootsect/mbr.asm

@@ -3,6 +3,8 @@
 
 	include '../common/const.inc'
 	include '../common/macro.inc'
+	include '../common/bios.inc'
+	include '../common/mbr.inc'
 
 	org MBR_BASE
 	cli
@@ -19,9 +21,60 @@
 	rep movsw
 	jmp 0x0:start
 start:
-	; TODO: read partition table and load bootable one.
+	; set LBA 
+	mov ah, 0x41
+	mov bx, 0x55AA
+	mov dl, 0x80
+	int 0x13
+	jc .error_lba
+	lea ecx, [PT1]
+.loop:
+	mov al, byte [ecx]
+	bt ax, 7
+	jc .found
+	lea eax, [PT4]
+	test eax, ecx
+	je .error_no_bootable
+	add cx, 0xF
+	jmp .loop
+.found:
+	mov eax, dword [ecx + Partition.lba]
+	mov [disk_packet_lba], eax
+	mov si, disk_packet
+	mov ah, 0x42
+	mov dl, 0x80
+	int 13
+	jc .error_load
+	jmp 0x0:BOOTSECT_BASE
+.error_lba:
+	mov si, msg_error_lba
+	jmp .error_print
+.error_no_bootable:
+	mov si, msg_error_bootable
+	jmp .error_print
+.error_load:
+	mov si, msg_error_load
+.error_print:
+	call bios_print
+.end:
+	hlt
+	jmp $
 
-	times 436-($-$$) db 0x90
+disk_packet:
+	db 0x10
+	db 0
+	dw 1
+	dw BOOTSECT_BASE
+	dw 0x0
+disk_packet_lba:
+	dd 0x0
+	dw 0x0
+
+msg_error_lba db "We don't support CHS", CR, LF, 0
+msg_error_bootable db "No bootable device found", CR, LF, 0
+msg_error_load db "Can't load partition", CR, LF, 0
+
+	rb MBR_BASE+0x1a8-$
 UID db 'STUPIDDISK'
 	; partition table
 PT1 db 16 dup(0)

boot/common/const.inc

@@ -10,6 +10,9 @@ DISK_BUFFER    = 0x8000
 KERNEL_PRELOAD = 0xF000
 STACK_TOP      = 0x7000
 
+; ---------- Magic ------------
+STPDBOOT_MAGIC = 0x53545044
+
 ; ---------- Video ------------
 VIDEO_WIDTH  = 1024
 VIDEO_HEIGHT = 768

boot/common/mbr.inc

@@ -0,0 +1,15 @@
+	;; File: mbr.inc
+
+
+struc Partition
+{
+	.status    db ?
+	.chs_start db 3 dup(?)
+	.type      db ?
+	.chs_last  db 3 dup(?)
+	.lba       dd ?
+	.sectors   dd ?
+}
+defn Partition
+
+

boot/intro.txt

@@ -50,3 +50,4 @@ Section: UEFI (IA32)
 > | BOOTIA32.EFI |----->| vmstupid.sys |
 > +--------------+      +--------------+
 >
+

boot/loader/Makefile

@@ -2,6 +2,9 @@ TARGET = stpdldr.sys
 
 LOADER_SRCS	= loader.asm \
 				../common/const.inc \
+				video.inc \
+				memory.inc \
+				logger.inc \
 				a20.inc \
 				multiboot.inc
 

boot/loader/loader.asm

@@ -27,20 +27,41 @@ _start:
 	push cs
 	pop ds
 
+	mov [drive_number], dl
+
 	mov si, msg_stage2
-	call bios_print
+	call bios_log
 
 	; enable A20 line
 	call a20_enable
 	jc .error_a20
 
+	; check drive type
+	; dl <= 0x7F == floppy
+	; dl >= 0x80 == hard drive
+	; dl == 0xE0 ~= CD/DVD
+	; dl <= 0xFF == hard drive
+	mov dl, [drive_number]
+	cmp dl, 0x7F
+	; skip disk extension check
+	jle @f 
+
+	; check disk extensions
+	mov ah, 0x41
+	mov bx, 0x55AA
+	int 0x13
+	jc @f
+	mov [drive_lba], 1
+@@:
+	; detect filesystem (FAT12/16 or StpdFS)
+	; load kernel from filesystem
+
     ; fetch memory map from bios
     call memory_get_map
     jc .error_memory
 
 	; video information
 	call video_setup
-	xchg bx, bx
 
 	; load GDT and enter Protected-Mode
 	lgdt [gdt_ptr]
@@ -65,21 +86,26 @@ _start:
 .error_a20:
 	mov si, msg_error_a20
 .error:
-	call bios_print
+	call bios_log
 @@:
 	hlt
 	jmp @b
 
 	include 'a20.inc'
 	include '../common/bios.inc'
+	include 'logger.inc'
 	include 'memory.inc'
 	include 'video.inc'
 	include 'gdt.inc'
 
-msg_stage2        db "StupidOS Loader", CR, LF, 0
+drive_number rb 1
+drive_lba    db 0
+
+msg_stage2        db "StupidOS Loader", 0
 kernel_fat12_file db "VMSTUPIDSYS", 0
-msg_error_a20     db "ERROR: can't enable a20 line", CR, LF, 0
+config_fat12_file db "BOOT    INI", 0
-msg_error_memory  db "ERROR: can't detect available memory", CR, LF, 0
+msg_error_a20     db "ERROR: can't enable a20 line", 0
+msg_error_memory  db "ERROR: can't detect available memory", 0
 
 	use32
 	; =========================================================================
@@ -101,6 +127,10 @@ common32:
 	; identity map first 1MB
 	; map kernel to 0xC0000000
 
+	push STPDBOOT_MAGIC
+
+	mov eax, 0xC0000000
+	jmp eax
 hang:
 	hlt
 	jmp $

boot/loader/logger.inc

@@ -0,0 +1,54 @@
+bios_log_time:
+	clc
+	mov ah, 0x02
+	int 0x1A
+
+	mov al, ch
+	aam
+	add ah, 0x30
+	add al, 0x30
+	mov [time + 1], ah
+	mov [time + 2], al
+
+	mov al, cl
+	aam
+	add ah, 0x30
+	add al, 0x30
+	mov [time + 4], ah
+	mov [time + 5], al
+
+	mov al, dh
+	aam
+	add ah, 0x30
+	add al, 0x30
+	mov [time + 7], ah
+	mov [time + 8], al
+
+	mov si, time
+	call bios_print
+
+	ret
+
+bios_log_hex:
+	ret
+
+	;; Function: bios_log
+	;;
+	;; Parameters:
+	;;     SI      - string to print
+	;;     [STACK] - variadic arguments
+	;;
+bios_log:
+	push si
+	call bios_log_time
+	pop si
+
+	call bios_print
+
+
+	mov si, endline
+	call bios_print
+	ret
+
+time db '[00:00.00] ', 0
+endline db CR, LF, 0

boot/loader/memory.inc

@@ -65,6 +65,9 @@ memory_e820_get_map:
 	;;     BX - Extended 2
 	;;     CX - Configured 1
 	;;     DX - Configured 2
+memory_get_for_large_conf:
+	mov ax, 0xE801
+	int 0x15
 
 	;; Function: memory_get_extended_memory_size
 	;;
@@ -75,4 +78,5 @@ memory_e820_get_map:
 	;;    CF - Non-Carry - indicates no error
 	;;    AX - Number of contiguous KB above 1MB
 memory_get_map:
+	clc
 	ret

boot/loader/multiboot.inc

@@ -82,6 +82,7 @@ struc MultibootData
         .fb_type   db ?
         .fb_misc   dw 3 dup ?
 }
+defn MultibootData
 
 MULTIBOOT_DATA_MEM             = 0x0001
 MULTIBOOT_DATA_BOOTDEV         = 0x0002
@@ -100,6 +101,7 @@ struc MultibootMMap
         .length dq ?
         .type   dd ?
 }
+defn MultibootMMap
 
 MULTIBOOT_MEMORY_AVAILABLE = 0x1
 MULTIBOOT_MEMORY_RESERVED  = 0x2
@@ -114,3 +116,4 @@ struc MultibootModule
 	.cmdline   dd ?
 	.pad       dd ?
 }
+defn MultibootModule

boot/loader/video.inc

@@ -14,6 +14,7 @@ struc VesaInfo
 	.Reserved              db 222 dup(?)
 	.OEMData               db 256 dup(?)
 }
+defn VesaInfo
 
 struc VesaModeInfo
 {
@@ -59,4 +60,29 @@ struc VesaModeInfo
 defn VesaModeInfo
 
 video_setup:
+	clc
+	mov di, [vesa_block_buffer]
+	mov ax, 0x4F00
+	int 0x10
+	cmp ax, 0x004F
+	jne .err
+
+	push word [vesa_block_buffer + VesaInfo.VideoModesSegment]
+	pop es
+	mov di, vesa_info_block_buffer
+	mov bx, [vesa_block_buffer + VesaInfo.VideoModesOffset]
+	mov cx, [bx]
+	cmp cx, 0xFFFF
+	je .err
+
+	mov ax, 0x4F01
+	int 0x10
+	cmp ax, 0x004F
+	jne .err
 	ret
+.err:
+	stc
+	ret
+
+vesa_block_buffer VesaInfo
+vesa_info_block_buffer VesaModeInfo

include/fs/fat16.h

@@ -2,6 +2,8 @@
 # define ECHFS_H 1
 
 typedef struct {
+	uint8_t jmp[4];
+	uint8_t signature[8];
 
 } EchFSIdentityTable;
 

kernel/kernel.asm

@@ -8,7 +8,15 @@
 
 	include 'mm/mm.inc'
 
+	;; Function: kmain
+	;;
+	;; Parameters:
+	;; 
+	;;     EAX - Boot Magic
+	;;     EBX - Boot structure address
+	;;
 kmain:
+	; TODO: interupt, vmm
 	nop
 
 _edata:

kernel/mm/mm.inc

@@ -1,6 +1,4 @@
 free_block_head dd 0x0
 
 mm_init:
-
 	ret
-		

lib/Makefile

@@ -1,4 +1,4 @@
-SUBDIRS = csu crypto lzp
+SUBDIRS = csu crypto lzp c
 
 TOPGOALS = all clean install
 

lib/c/Makefile

@@ -0,0 +1,20 @@
+TARGET	= libc.a
+OBJS	= ctype.o
+INCS	= stddef.h time.h ctype.h
+
+all: $(TARGET)
+
+$(TARGET): $(OBJS)
+	$(AR) rcs $@ $^
+
+%.o: %.asm
+	$(AS) $< $@
+
+clean:
+	$(RM) $(TARGET) $(OBJS)
+
+install: $(TARGET)
+	@ mkdir -p $(DESTDIR)$(LIBDIR)
+	install $(TARGET) $(DESTDIR)$(LIBDIR)
+	@ mkdir -p $(DESTDIR)$(INCDIR)
+	install $(INCS) $(DESTDIR)$(INCDIR)

lib/c/ctype.asm

@@ -0,0 +1,34 @@
+	format COFF
+	use32
+
+	public isdigit
+
+	section '.code' code
+
+	;; Function: isdigit
+	;;
+	;; Parameters:
+	;;
+	;;     [esp+8]  - character
+	;;
+	;; Returns:
+	;; 
+	;;     eax - 1 if digit otherwhise 0
+	;;
+isdigit:
+	push ebp
+	mov ebp, esp
+	mov al, '0'
+	mov cl, byte [esp+8]
+	cmp al, cl
+	jb @f
+	mov al, '9'
+	cmp al, cl
+	jg @f
+	mov eax, 1
+	jmp .end 
+@@:
+	xor eax, eax
+.end:
+	leave
+	ret

lib/c/ctype.h

@@ -0,0 +1,7 @@
+#ifndef CTYPE_H
+# define CTYPE_H 1
+
+int isalnum(int c);
+int isdigit(int c);
+
+#endif /* !CTYPE_H */

lib/c/stddef.h

@@ -0,0 +1,6 @@
+#ifndef STDDEF_H
+# define STDDEF_H 1
+
+typedef unsigned int size_t;
+
+#endif /* !STDDEF_H */

lib/c/time.h

@@ -0,0 +1,31 @@
+#ifndef TIME_H
+# define TIME_H 1
+
+# include <stdint.h>
+
+/* POSIX define CLOCKS_PER_SEC as on milion */
+# define CLOCKS_PER_SEC 1000000
+
+typedef int64_t time_t;
+typedef uint64_t clock_t;
+
+struct tm {
+	int tm_sec;
+	int tm_min;
+	int tm_hour;
+	int tm_mday;
+	int tm_mon;
+	int tm_year;
+	int tm_wday;
+	int tm_yday;
+	int tm_isdst;
+};
+
+double difftime(time_t time_end, time_t time_beg);
+time_t time(time_t *arg);
+clock_t clock(void);
+char *asctime(const struct tm *time); /* fuck modern C */
+char *ctime(const time_t *timer);
+size_t strftime(char *str, size_t count, const char *format, const struct tm *tp);
+
+#endif /* !TIME_H */

sbin/mkfs.stpd/main.c

@@ -0,0 +1,175 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <string.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <sys/stat.h>
+
+#define MAGIC 0x44505453
+
+#define BLOCK_SIZE 512
+
+struct superblock {
+	uint32_t magic;
+	uint32_t isize;
+	uint32_t fsize;
+	uint32_t free[100];
+	uint8_t nfree;
+	uint8_t flock;
+	uint8_t ilock;
+	uint8_t fmod;
+	uint32_t time[2];
+} __attribute__((packed));
+
+struct inode {
+	uint16_t mode;
+	uint8_t nlink;
+	uint8_t uid;
+	uint8_t gid;
+	uint32_t size;
+	uint16_t addr[8];
+	uint32_t actime[2];
+	uint32_t modtime[2];
+} __attribute__((packed));
+
+#define INODE_SIZE sizeof(struct inode)
+
+struct file {
+	unsigned short inode;
+	char filename[14];
+};
+
+static const char *prg_name = NULL;
+static int verbose = 0;
+static const char *device = NULL;
+static int devfd = 0;
+static off_t device_size = 0;
+
+static int
+write_sector(size_t secnum, const uint8_t *data, size_t buff_size)
+{
+	uint8_t buffer[BLOCK_SIZE];
+
+	if (lseek(devfd, secnum * BLOCK_SIZE, SEEK_SET) != (secnum * BLOCK_SIZE))
+	{
+		fprintf(stderr, "%s: %s\n", device, strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+
+	memset(buffer, 0, BLOCK_SIZE);
+	memcpy(buffer, data, buff_size);
+
+	if (write(devfd, buffer, BLOCK_SIZE) != BLOCK_SIZE)
+	{
+		fprintf(stderr, "%s: x %s\n", device, strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+}
+
+static void
+usage(int retcode)
+{
+	if (retcode == EXIT_FAILURE)
+	{
+		fprintf(stderr, "Try '%s -h' for more informations.\n", prg_name);
+	}
+	else
+	{
+		printf("Usage: %s [-hVv] disk\n", prg_name);
+		printf("\t-h\tdisplay this help and exit\n");
+		printf("\t-V\toutput version information.\n");
+		printf("\nReport bugs to <%s>\n", MK_BUGREPORT);
+	}
+
+	exit(retcode);
+}
+
+static void
+version(void)
+{
+	printf("%s commit %s\n", prg_name, MK_COMMIT);
+	exit(EXIT_SUCCESS);
+}
+
+int
+main(int argc, char **argv)
+{
+	struct stat inf;
+	int idx;
+	uint8_t buffer[BLOCK_SIZE];
+	struct superblock sb;
+
+	prg_name = argv[0];
+
+	while ((argc > 1) && (argv[1][0]) == '-')
+	{
+		switch (argv[1][1])
+		{
+			case 'h':
+				usage(EXIT_SUCCESS);
+				break;
+			case 'V':
+				version();
+				break;
+			case 'v':
+				verbose=1;
+				break;
+			default:
+				usage(EXIT_FAILURE);
+		}
+		argv++;
+		argc--;
+	}
+
+	if (argc <= 1) usage(EXIT_FAILURE);
+
+	device = argv[1];
+
+	if (stat(device, &inf) != 0)
+	{
+		fprintf(stderr, "%s: %s\n", device, strerror(errno));
+		return (EXIT_FAILURE);
+	}
+
+	device_size = inf.st_size;
+
+	if (verbose) printf("Device size: %ld (%ld blocks)\n", device_size, device_size/BLOCK_SIZE);
+
+	/*if (device_size/BLOCK_SIZE > 0x7fff)
+	{
+		fprintf(stderr, "%s: File too large\n", device);
+		return (EXIT_FAILURE);
+	}*/
+
+	/* */
+
+	devfd = open(device, O_WRONLY);
+	if (devfd < 0)
+	{
+		fprintf(stderr, "%s: %s\n", device, strerror(errno));
+		return (EXIT_FAILURE);
+	}
+
+	memset(buffer, 0, BLOCK_SIZE);
+	for (idx = 0; idx < device_size/BLOCK_SIZE; idx++)
+	{
+		write_sector(idx, buffer, BLOCK_SIZE);
+	}
+	if (verbose) printf("Write %ld (%ld bytes)\n", device_size/BLOCK_SIZE, device_size);
+
+	memset(&sb, 0, sizeof(struct superblock));
+
+	sb.magic = MAGIC;
+	sb.fsize = device_size/BLOCK_SIZE;
+
+	write_sector(1, (uint8_t *)&sb, sizeof(struct superblock));
+
+	//sb.ninode = (device_size/BLOCK_SIZE) / 8;
+
+	printf("sizeof %lu %lu\n", sizeof(struct superblock), sizeof(struct inode));
+
+	close(devfd);
+
+	return (EXIT_SUCCESS);
+}

sbin/mkfs.stpd/v6.5

@@ -0,0 +1,304 @@
+
+V6/usr/man/man5/fs.5
+Compare this file to the similar file:
+
+Show the results in this format:
+
+.TH "FILE SYSTEM" V 2/9/75
+.SH NAME
+fs \*- format of file system volume
+.SH DESCRIPTION
+Every
+file system storage volume
+(e.g. RF disk, RK disk, RP disk, DECtape reel)
+has a common format for certain vital information.
+Every such volume is divided into a certain number
+of 256 word (512 byte) blocks.
+Block 0 is unused and is available to contain
+a bootstrap program, pack label, or other information.
+.s3
+Block 1 is the
+.IB "super block."
+Starting from its first word, the format of a super-block is
+.s3
+.nf
+struct {
+	int	isize;
+	int	fsize;
+	int	nfree;
+	int	free[100];
+	int	ninode;
+	int	inode[100];
+	char	flock;
+	char	ilock;
+	char	fmod;
+	int	time[2];
+};
+.s3
+.fi
+.IP Isize
+is the number of blocks devoted to the i-list,
+which starts just after the super-block, in block 2.
+.IP Fsize
+is the first block not potentially available for allocation
+to a file.
+These numbers are used by the system to
+check for bad block numbers;
+if an ``impossible'' block number is allocated from the free list
+or is freed,
+a diagnostic is written on the on-line console.
+Moreover, the free array is cleared, so as to prevent further
+allocation from a presumably corrupted free list.
+.s3
+The free list for each volume is maintained as
+follows.
+The
+.IB free
+array contains, in
+.IB "free[1], ... , free[nfree\*-1],"
+up to 99 numbers of free blocks.
+.IB Free[0]
+is the block number of the head
+of a chain of blocks constituting the free list.
+The first word in each free-chain block is the number
+(up to 100) of free-block numbers listed in the
+next 100 words of this chain member.
+The first of these 100 blocks is the link to the
+next member of the chain.
+To allocate a block:
+decrement
+.IB nfree,
+and the new block is
+.IB free[nfree].
+If the new block number is 0,
+there are no blocks left, so give an error.
+If
+.IB nfree
+became 0,
+read in the block named by the new block number,
+replace
+.IB nfree
+by its first word,
+and copy the block numbers in the next 100 words into the
+.IB free
+array.
+To free a block, check if
+.IB nfree
+is 100; if so,
+copy
+.IB nfree
+and the
+.IB free
+array into it,
+write it out, and set
+.IB nfree
+to 0.
+In any event set
+.IB free[nfree]
+to the freed block's number and
+increment
+.IB nfree.
+.s3
+.IB Ninode
+is the number of free i-numbers in the
+.IB inode
+array.
+To allocate an i-node:
+if
+.IB ninode
+is greater than 0,
+decrement it and return
+.IB inode[ninode].
+If it was 0, read the i-list
+and place the numbers of all free inodes
+(up to 100) into the
+.IB inode
+array,
+then try again.
+To free an i-node,
+provided
+.IB ninode
+is less than 100,
+place its number into
+.IB inode[ninode]
+and increment
+.IB ninode.
+If
+.IB ninode
+is already 100, don't bother to enter the freed i-node into any table.
+This list of i-nodes is only to speed
+up the allocation process; the information
+as to whether the inode is really free
+or not is maintained in the inode itself.
+.s3
+.IB Flock
+and
+.IB ilock
+are flags maintained in the core
+copy of the file system
+while it is mounted
+and their values on disk are immaterial.
+The value of
+.IB fmod
+on disk is likewise immaterial;
+it is used as a flag to indicate that the super-block has
+changed and should be copied to
+the disk during the next periodic update of file
+system information.
+.s3
+.IB Time
+is the last time the super-block of the file system was changed,
+and is a double-precision representation
+of the number of seconds that have elapsed
+since
+0000 Jan. 1 1970 (GMT).
+During a reboot, the
+.IB time
+of the super-block for the root file system
+is used to set the system's idea of the time.
+.s3
+I-numbers begin at 1, and the storage for i-nodes
+begins in block 2.
+.tr |
+Also, i-nodes are 32 bytes long, so 16 of them fit into a block.
+Therefore, i-node
+.IB i
+is located in block (\fIi\fR|+|31)|/|16, and begins
+32\u\fB.\fR\d((\fIi\fR|+|31)|(mod 16) bytes from its start.
+I-node 1 is reserved for the root directory of the file
+system, but no other i-number has a built-in
+meaning.
+Each i-node represents one file.
+The format of an i-node is as follows.
+.s3
+.nf
+.if t .ta .5i 1.i 2.5i
+struct {
+	int	flags;	/* +0: see below */
+	char	nlinks;	/* +2: number of links to file */
+	char	uid;	/* +3: user ID of owner */
+	char	gid;	/* +4: group ID of owner */
+	char	size0;	/* +5: high byte of 24-bit size */
+	int	size1;	/* +6: low word of 24-bit size */
+	int	addr[8];	/* +8: block numbers or device number */
+	int	actime[2];	/* +24: time of last access */
+	int	modtime[2];	/* +28: time of last modification */
+};
+.dt
+.fi
+.s3
+The flags are as follows:
+.s3
+.lp +10 9
+100000	i-node is allocated
+.lp +10 9
+060000	2-bit file type:
+.lp +15 9
+000000	plain file
+.lp +15 9
+040000	directory
+.lp +15 9
+020000	character-type special file
+.lp +15 9
+060000	block-type special file.
+.lp +10 9
+010000	large file
+.lp +10 9
+004000	set user-ID on execution
+.lp +10 9
+002000	set group-ID on execution
+.lp +10 9
+000400	read (owner)
+.lp +10 9
+000200	write (owner)
+.lp +10 9
+000100	execute (owner)
+.lp +10 9
+000070	read, write, execute (group)
+.lp +10 9
+000007	read, write, execute (others)
+.s3
+.i0
+Special files are recognized by their flags
+and not by i-number.
+A block-type special file is basically one which
+can potentially be mounted as a file system;
+a character-type special file cannot, though it is
+not necessarily character-oriented.
+For special files the high byte of the first address word
+specifies the type of device; the low byte specifies
+one of several devices of
+that type.
+The device type numbers
+of block and character special files overlap.
+.s3
+The address words of ordinary files and directories
+contain the numbers of the blocks in the
+file (if it is small)
+or the numbers of indirect blocks (if the file
+is large).
+Byte number
+.IB n
+of a file is accessed as follows.
+.IB N
+is divided by 512 to find its logical block number
+(say
+.IB b
+)
+in the file.
+If the file is small (flag 010000 is 0),
+then
+.IB b
+must be less than 8, and the physical
+block number is
+.IB addr[b].
+.s3
+If the file is large,
+.IB b
+is divided by 256 to yield
+.IB i.
+If
+.IB i
+is less than 7, then
+.IB addr[i]
+is the physical block number of
+the indirect block.
+The remainder from the division 
+yields the word in the indirect block
+which contains the number of the block for
+the sought-for byte.
+.s3
+If
+.IB i
+is equal to 7,
+then the file has become extra-large (huge),
+and
+.IB addr[7]
+is the address of a first indirect block.
+Each word in this block
+is the number of a second-level indirect block;
+each word in the second-level indirect blocks points to a data block.
+Notice that extra-large files are not marked by any mode
+bit, but only by having
+.IB addr[7]
+non-zero;
+and that although this scheme allows for more than
+256\*X256\*X512 = 33,554,432 bytes per file,
+the length of files is stored in 24 bits
+so in practice a file can be at most
+16,777,216 bytes long.
+.s3
+For block
+.IB b
+in a file to exist,
+it
+is not necessary that all blocks less than
+.IB b
+exist.
+A zero block number either in the address words of
+the i-node or in an indirect block indicates that the
+corresponding block has never been allocated.
+Such a missing block reads as if it contained all zero words.
+.SH "SEE ALSO"
+icheck, dcheck (VIII)
+

tools/Makefile

@@ -1,7 +1,7 @@
 CC	= gcc
 RM	= rm -f
 
-TARGET	= fat$(EXEXT) coff-ld$(EXEXT) parted$(EXEXT)
+TARGET	= fat$(EXEXT) coff-ld$(EXEXT) parted$(EXEXT) mkfs.stpd$(EXEXT)
 
 CFLAGS	= -DMK_COMMIT="$(MK_COMMIT)" -DMK_BUGREPORT="$(MK_BUGREPORT)" -I../include
 LDFLAGS	=
@@ -18,6 +18,9 @@ coff-ld$(EXEXT): coff-ld.c
 parted$(EXEXT): ../sbin/parted/main.c
 	$(CC) -o $@ $^ $(CFLAGS) $(LDFLAGS)
 
+mkfs.stpd$(EXEXT): ../sbin/mkfs.stpd/main.c
+	$(CC) -o $@ $^ $(CFLAGS) $(LDFLAGS)	
+
 .PHONY: install
 install: $(TARGET)