From Lucho:

SYS 3.0 changes: added /L parameter to SYS to be able to change the kernel
boot segment + a few boot sector changes to get the pointer at the same
magic place for all boot sectors.


git-svn-id: https://svn.code.sf.net/p/freedos/svn/kernel/trunk@751 6ac86273-5f31-0410-b378-82cca8765d1b

boot/boot.asm

@@ -139,10 +139,8 @@ Entry:          jmp     short real_start
 
 		times	0x3E-$+$$ db 0
 
-%define loadsegoff_60         bp+0x3E
+%define loadsegoff_60	bp+loadseg_off-Entry
-                dw      0
+%define loadseg_60	bp+loadseg_seg-Entry
-%define loadseg_60         bp+0x40
-                dw      LOADSEG
 
 ;%define LBA_PACKET      bp+0x42
 ;		db      10h  ; size of packet
@@ -199,6 +197,9 @@ real_start:
 		rep	movsw
                 jmp     word 0x1FE0:cont
 
+loadseg_off	dw	0
+loadseg_seg	dw	LOADSEG
+
 cont:
 		mov     ds, ax
 		mov	ss, ax

boot/boot32.asm

@@ -65,10 +65,8 @@ Entry:          jmp     short real_start
 
 %define fat_sector      bp+0x48         ; last accessed sector of the FAT
 
-%define loadsegoff_60	bp+0x5a         ; FAR pointer = 60:0
+%define loadsegoff_60	bp+loadseg_off-Entry ; FAR pointer = 60:0
-                dw      0
+%define loadseg_60	bp+loadseg_seg-Entry
-%define loadseg_60	bp+0x5c
-                dw      LOADSEG
 
 %define fat_start       bp+0x5e         ; first FAT sector
 %define data_start      bp+0x62         ; first data sector
@@ -93,6 +91,9 @@ real_start:     cld
 		rep	movsw           ; move boot code to the 0x1FE0:0x0000
 		jmp     word 0x1FE0:cont
 
+loadseg_off	dw	0
+loadseg_seg	dw	LOADSEG
+
 cont:           mov     ds, ax
                 mov     ss, ax
                 lea     sp, [bp-0x20]

boot/boot32lb.asm

@@ -81,6 +81,7 @@ Entry:		jmp	short real_start
 			; +0x32 dw -1 or sector number of boot sector backup
 			; (+0x34 .. +0x3f reserved)
 %define drive		bp+0x40	; Drive number
+%define loadsegoff_60	bp+loadseg_off-Entry
 
 %define LOADSEG		0x0060
 
@@ -107,24 +108,27 @@ Entry:		jmp	short real_start
 ;-----------------------------------------------------------------------
 
 real_start:	cld
+		cli
 		sub	ax, ax
 		mov	ds, ax
-		lss	sp, [mystack]	; initialize stack
+		mov	bp, 0x7c00
-		int	0x13		; reset drive
 
 		mov	ax, 0x1FE0
 		mov	es, ax
-		mov	si, sp
+		mov	si, bp
-		mov	di, sp
+		mov	di, bp
-		mov 	bp, sp		; bp-relative parameter addresses used
 		mov	cx, 0x0100
 		rep	movsw		; move boot code to the 0x1FE0:0x0000
 		jmp	word 0x1FE0:cont
 
+loadseg_off	dw	0, LOADSEG
+
 ; -------------
 
 cont:		mov	ds, ax
 		mov	ss, ax		; stack and BP-relative moves up, too
+                lea     sp, [bp-0x20]
+		sti
 		mov	[drive], dl	; BIOS passes drive number in DL
 
 		mov	si, msg_LoadFreeDOS
@@ -177,9 +181,7 @@ ff_next_clust:	push	eax			; save cluster
 		jc	boot_error		; EOC encountered
 		; EDX is clust/sector, EAX is sector
 				
-ff_next_sector:	mov	bx, LOADSEG
+ff_next_sector:	les	bx, [loadsegoff_60]	; load to loadseg:0
-		mov	es, bx
-		sub	bx, bx			; load to loadseg:0
 		call	readDisk
 ;---		push	eax			; save sector
 
@@ -233,7 +235,7 @@ rk_walk_fat:	pop	eax
 ;-----------------------------------------------------------------------
 
 boot_success:	mov	bl, [drive]
-		jmp	word LOADSEG:0
+		jmp	far [loadsegoff_60]
 
 ;-----------------------------------------------------------------------
 
@@ -389,9 +391,6 @@ no_incr_es:	pop	di
 
 msg_LoadFreeDOS db "Loading FreeDOS ",0
 
-mystack        dw 0x7c00   ; the 0 for SS overlaps into pad bytes!
-       ; (so we can LSS SP to 0:7c00)
-
        times 0x01ee-$+$$ db 0
 
 msg_BootError	db "No "

sys/sys.c

@@ -29,7 +29,7 @@
 #define DEBUG
 /* #define DDEBUG */
 
-#define SYS_VERSION "v2.9"
+#define SYS_VERSION "v3.0"
 
 #include <stdlib.h>
 #include <dos.h>
@@ -159,7 +159,7 @@ char *getenv(const char *name)
 
 BYTE pgm[] = "SYS";
 
-void put_boot(int, char *, char *, int);
+void put_boot(int, char *, char *, int, int);
 BOOL check_space(COUNT, ULONG);
 BOOL copy(COUNT drive, BYTE * srcPath, BYTE * rootPath, BYTE * file);
 
@@ -254,6 +254,7 @@ int main(int argc, char **argv)
   int bootonly = 0;
   int both = 0;
   char *kernel_name = "KERNEL.SYS";
+  int load_segment = 0x60;
 
   printf("FreeDOS System Installer " SYS_VERSION ", " __DATE__ "\n\n");
 
@@ -278,6 +279,11 @@ int main(int argc, char **argv)
       argno++;
       kernel_name = argv[argno];
     }
+    else if (argp[0] == '/' && toupper(argp[1]) == 'L' && argno + 1 < argc)
+    {
+      argno++;
+      load_segment = (int)strtol(argv[argno], NULL, 16);
+    }
     else if (memicmp(argp, "BOOTONLY", 8) == 0 && !bootonly)
     {
       bootonly = 1;
@@ -303,7 +309,7 @@ int main(int argc, char **argv)
   if (drivearg == 0)
   {
     printf(
-      "Usage: %s [source] drive: [bootsect [BOTH]] [BOOTONLY] [/K name]\n"
+      "Usage: %s [source] drive: [bootsect [BOTH]] [BOOTONLY] [/K name] [/L segm]\n"
       "  source   = A:,B:,C:\\KERNEL\\BIN\\,etc., or current directory if not given\n"
       "  drive    = A,B,etc.\n"
       "  bootsect = name of 512-byte boot sector file image for drive:\n"
@@ -311,6 +317,7 @@ int main(int argc, char **argv)
       "  BOTH     : write to *both* the real boot sector and the image file\n"
       "  BOOTONLY : do *not* copy kernel / shell, only update boot sector or image\n"
       "  /K name  : name of kernel to use instead of KERNEL.SYS\n"
+      "  /L segm  : hex load segment to use instead of 60\n"
       "%s CONFIG /help\n", pgm, pgm);
     exit(1);
   }
@@ -362,7 +369,7 @@ int main(int argc, char **argv)
     sprintf(rootPath, "%c:\\", 'A' + srcDrive);
 
   printf("Processing boot sector...\n");
-  put_boot(drive, bsFile, kernel_name, both);
+  put_boot(drive, bsFile, kernel_name, load_segment, both);
 
   if (!bootonly)
   {
@@ -662,7 +669,7 @@ BOOL haveLBA(void)
 }
 #endif
 
-void put_boot(int drive, char *bsFile, char *kernel_name, int both)
+void put_boot(int drive, char *bsFile, char *kernel_name, int load_seg, int both)
 {
 #ifdef WITHFAT32
   struct bootsectortype32 *bs32;
@@ -756,6 +763,12 @@ void put_boot(int drive, char *bsFile, char *kernel_name, int both)
     bs32 = (struct bootsectortype32 *)&newboot;
     /* put 0 for A: or B: (force booting from A:), otherwise use DL */
     bs32->bsDriveNumber = drive < 2 ? 0 : 0xff;
+    /* the location of the "0060" segment portion of the far pointer
+       in the boot sector is just before cont: in boot*.asm.
+       This happens to be offset 0x78 (=0x3c * 2) for FAT32 and
+       offset 0x5c (=0x2e * 2) for FAT16 */
+    /* i.e. BE CAREFUL WHEN YOU CHANGE THE BOOT SECTORS !!! */
+    ((int *)newboot)[0x3C] = load_seg;
 #ifdef DEBUG
     printf(" FAT starts at sector %lx + %x\n",
            bs32->bsHiddenSecs, bs32->bsResSectors);
@@ -766,6 +779,7 @@ void put_boot(int drive, char *bsFile, char *kernel_name, int both)
   {
     /* put 0 for A: or B: (force booting from A:), otherwise use DL */
     bs->bsDriveNumber = drive < 2 ? 0 : 0xff;
+    ((int *)newboot)[0x2E] = load_seg;
   }
 
 #ifdef DEBUG /* add an option to display this on user request? */
@@ -801,6 +815,7 @@ void put_boot(int drive, char *bsFile, char *kernel_name, int both)
 #ifdef DEBUG
   /* there's a zero past the kernel name in all boot sectors */
   printf("Boot sector kernel name set to %s\n", &newboot[0x1f1]);
+  printf("Boot sector load segment set to %Xh\n", load_seg);
 #endif
 
 #ifdef DDEBUG