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authorhpa <hpa>2002-06-02 05:12:25 +0000
committerhpa <hpa>2002-06-02 05:12:25 +0000
commitf3d5f4fd208cc58d58e0a000595848bde49b2dbb (patch)
treeaf98774e9c4d27c37c0d2b6eefa570679140ad67
parent5823e4914a21a2aecb58345716f851407612d63e (diff)
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Major rewrite of the very early SYSLINUX code. Generate the "stupid"
version in a different manner. Require NASM 0.98.32 or higher -- thus we don't need the jmpcc macros anymore.
-rw-r--r--Makefile32
-rw-r--r--NEWS16
-rwxr-xr-xfindpatch.pl25
-rw-r--r--genstupid.pl77
-rw-r--r--ldlinux.asm623
-rw-r--r--macros.inc51
-rw-r--r--runkernel.inc21
-rw-r--r--syslinux.asm10
-rw-r--r--syslinux.c24
-rw-r--r--version2
10 files changed, 411 insertions, 470 deletions
diff --git a/Makefile b/Makefile
index 927ed36d..dc49060b 100644
--- a/Makefile
+++ b/Makefile
@@ -20,7 +20,7 @@ INCLUDE =
CFLAGS = -Wall -O2 -fomit-frame-pointer
LDFLAGS = -O2 -s
-NASM = nasm
+NASM = nasm -O99
NINCLUDE =
BINDIR = /usr/bin
LIBDIR = /usr/lib/syslinux
@@ -41,11 +41,11 @@ CSRC = syslinux.c gethostip.c
NASMSRC = ldlinux.asm syslinux.asm copybs.asm \
pxelinux.asm mbr.asm isolinux.asm isolinux-debug.asm
SOURCES = $(CSRC) $(NASMSRC) *.inc
-BTARGET = kwdhash.gen ldlinux.bss ldlinux.sys ldlinux.bin ldlinux.lst \
+BTARGET = kwdhash.gen ldlinux.bss ldlinux.sys ldlinux.bin \
pxelinux.0 mbr.bin isolinux.bin isolinux-debug.bin
ITARGET = syslinux.com syslinux copybs.com gethostip
DOCS = COPYING NEWS README TODO *.doc sample
-OTHER = Makefile bin2c.pl now.pl genhash.pl keywords genstupid.pl \
+OTHER = Makefile bin2c.pl now.pl genhash.pl keywords findpatch.pl \
keytab-lilo.pl version sys2ansi.pl ppmtolss16 lss16toppm memdisk
OBSOLETE = pxelinux.bin
@@ -113,11 +113,15 @@ ldlinux.bss: ldlinux.bin
ldlinux.sys: ldlinux.bin
dd if=ldlinux.bin of=ldlinux.sys bs=512 skip=1
+patch.offset: ldlinux.sys findpatch.pl
+ $(PERL) findpatch.pl > patch.offset
+
mbr.bin: mbr.asm
$(NASM) -f bin -l mbr.lst -o mbr.bin mbr.asm
-syslinux.com: syslinux.asm ldlinux.bss ldlinux.sys stupid.gen
- $(NASM) -f bin -l syslinux.lst -o syslinux.com syslinux.asm
+syslinux.com: syslinux.asm ldlinux.bss ldlinux.sys patch.offset
+ $(NASM) -f bin -DPATCH_OFFSET=`cat patch.offset` \
+ -l syslinux.lst -o syslinux.com syslinux.asm
copybs.com: copybs.asm
$(NASM) -f bin -l copybs.lst -o copybs.com copybs.asm
@@ -128,20 +132,12 @@ bootsect_bin.c: ldlinux.bss bin2c.pl
ldlinux_bin.c: ldlinux.sys bin2c.pl
$(PERL) bin2c.pl ldlinux < ldlinux.sys > ldlinux_bin.c
-syslinux: syslinux.o bootsect_bin.o ldlinux_bin.o stupid.o
+syslinux: syslinux.o bootsect_bin.o ldlinux_bin.o
$(CC) $(LDFLAGS) -o syslinux \
- syslinux.o bootsect_bin.o ldlinux_bin.o stupid.o
-
-ldlinux.lst: ldlinux.bin
- : Generated by side effect
-
-stupid.c: ldlinux.lst genstupid.pl
- $(PERL) genstupid.pl < ldlinux.lst
-
-stupid.gen: stupid.c
- : Generated by side effect
+ syslinux.o bootsect_bin.o ldlinux_bin.o
-stupid.o: stupid.c
+syslinux.o: syslinux.c patch.offset
+ $(CC) $(INCLUDE) $(CFLAGS) -DPATCH_OFFSET=`cat patch.offset` -c -o $@ $<
gethostip.o: gethostip.c
@@ -153,7 +149,7 @@ install: installer
install -m 644 -c $(INSTALL_LIB) $(INSTALLROOT)$(LIBDIR)
local-tidy:
- rm -f *.o *_bin.c stupid.*
+ rm -f *.o *_bin.c stupid.* patch.offset
rm -f syslinux.lst copybs.lst pxelinux.lst isolinux*.lst
rm -f $(OBSOLETE)
diff --git a/NEWS b/NEWS
index 0c93cd07..ad1fa6d9 100644
--- a/NEWS
+++ b/NEWS
@@ -1,6 +1,22 @@
Starting with 1.47, changes marked with SYSLINUX/PXELINUX/ISOLINUX
apply to that specific program only; other changes apply to both.
+Changes in 1.75:
+ * ALL: NASM 0.98.32 or later is now required to build NASM
+ from sources.
+ * SYSLINUX: put back in the workaround for the BIOS floppy
+ table. This seems to be a requirement for "extended" floppy
+ formats to work correctly.
+ * SYSLINUX: No longer warn if one is trying to boot on a 286
+ or older. The above BIOS workaround no longer fits if the
+ requirement to use only 8086-compatible code in the early
+ boot is maintained. It made sense in 1994, but in 2002 a
+ 286 or older is a museum object.
+ * SYSLINUX: Use a downright bizarre, stateful algorithm to try
+ to guess the maximum transfer size. I am *hoping* this will
+ cut down on the number of systems for which -s is required
+ to work at any acceptable speed.
+
Changes in 1.74:
* SYSLINUX: fix bug that would cause valid kernel images to be
labelled "invalid".
diff --git a/findpatch.pl b/findpatch.pl
new file mode 100755
index 00000000..ac8ee5c8
--- /dev/null
+++ b/findpatch.pl
@@ -0,0 +1,25 @@
+#!/usr/bin/perl
+#
+# Script to find the "patch area" of ldlinux.sys
+#
+
+open(SYS, "< ldlinux.sys") or die "$0: Cannot open ldlinux.sys\n";
+if ( read(SYS,$sec1,512) != 512 ) {
+ die "$0: ldlinux.sys: short read\n";
+}
+close(SYS);
+
+for ( $i = 0 ; $i < 512; $i++ ) {
+ $scan = substr($sec1,$i,12);
+
+ if ( $scan eq "\032LDLINUX SYS" &&
+ substr($sec1,$i+16,2) eq "\x55\xAA" ) {
+ last;
+ }
+}
+
+
+die "$0: Did not find patch area signature\n" unless ( $i < 512 );
+
+# Past signature, plus align to the subsequent dword.
+print ((($i+18)+3) & ~3); print "\n";
diff --git a/genstupid.pl b/genstupid.pl
deleted file mode 100644
index 9adf8ef4..00000000
--- a/genstupid.pl
+++ /dev/null
@@ -1,77 +0,0 @@
-#ident "$Id$"
-## -----------------------------------------------------------------------
-##
-## Copyright 1998-2002 H. Peter Anvin - All Rights Reserved
-##
-## This program is free software; you can redistribute it and/or modify
-## it under the terms of the GNU General Public License as published by
-## the Free Software Foundation, Inc., 675 Mass Ave, Cambridge MA 02139,
-## USA; either version 2 of the License, or (at your option) any later
-## version; incorporated herein by reference.
-##
-## -----------------------------------------------------------------------
-
-#
-# This file is part of the SYSLINUX compilation sequence.
-#
-
-undef $addr, $begin, $end;
-$isbegin = 0; $isend = 0;
-
-while ( $line = <STDIN> ) {
- if ( $line =~ /^\s*([0-9]+) ([0-9A-F]{8}) / ) {
- $addr = hex $2;
- if ( $isbegin ) {
- $begin = $addr;
- $isbegin = 0;
- }
- if ( $isend ) {
- $end = $addr;
- $isend = 0;
- }
- }
- if ( $line =~ /^[0-9A-F\s]+__BEGIN_STUPID_PATCH_AREA\:/ ) {
- $isbegin = 1;
- } elsif ( $line =~ /^[0-9A-F\s]+__END_STUPID_PATCH_AREA\:/ ) {
- $isend = 1;
- }
-}
-
-if ( !defined($begin) || !defined($end) || $end > 512 || ($end-$begin) < 3 ) {
- print STDERR "$0: error locating STUPID_PATCH_AREA\n";
- exit 1;
-}
-
-open(CFILE, "> stupid.c") || die "$0: cannot create stupid.c: $!\n";
-
-$addr = $begin;
-printf CFILE "extern unsigned char bootsect[];\n";
-printf CFILE "void make_stupid(void)\n";
-printf CFILE "{\n";
-printf CFILE "\tbootsect[0x%x] = 0xbd;\n", $addr++;
-printf CFILE "\tbootsect[0x%x] = 0x01;\n", $addr++;
-printf CFILE "\tbootsect[0x%x] = 0x00;\n", $addr++;
-while ( $addr < $end ) {
- printf CFILE "\tbootsect[0x%x] = 0x90;\n", $addr++;
-}
-print CFILE "}\n";
-
-close(CFILE);
-
-open(ASMFILE, "> stupid.gen") || die "$0: cannot open stupid.inc: $!\n";
-
-printf ASMFILE "\tsection .text\n";
-printf ASMFILE "make_stupid:\n";
-printf ASMFILE "\tmov si, .stupid_patch\n";
-printf ASMFILE "\tmov di, BootSector+0%Xh\n", $begin;
-printf ASMFILE "\tmov cx, %d\n", $end-$begin;
-printf ASMFILE "\trep movsb\n";
-printf ASMFILE "\tret\n";
-printf ASMFILE "\tsection .data\n";
-printf ASMFILE ".stupid_patch:\n";
-printf ASMFILE "\tmov bp,1\n";
-for ( $addr = $begin + 3 ; $addr < $end ; $addr++ ) {
- printf ASMFILE "\tnop\n";
-}
-
-close(ASMFILE);
diff --git a/ldlinux.asm b/ldlinux.asm
index ad82045b..9107334f 100644
--- a/ldlinux.asm
+++ b/ldlinux.asm
@@ -118,8 +118,21 @@ KbdMap resb 256 ; Keyboard map
FKeyName resb 10*16 ; File names for F-key help
NumBuf resb 15 ; Buffer to load number
NumBufEnd resb 1 ; Last byte in NumBuf
+ alignb 8
+
+ ; Expanded superblock
+SuperInfo equ $
+ resq 16 ; The first 16 bytes expanded 8 times
+ ;
+ ; These need to follow SuperInfo
+ ;
+RootDir resd 1 ; Location of root directory
+DataArea resd 1 ; Location of data area
+RootDirSize resw 1 ; Root dir size in sectors
+DirScanCtr resw 1 ; Used while searching directory
+EndofDirSec resw 1 ; = trackbuf+bsBytesPerSec-31
+
alignb 4
-PartInfo resb 16 ; Partition table entry
E820Buf resd 5 ; INT 15:E820 data buffer
HiLoadAddr resd 1 ; Address pointer for high load loop
HighMemSize resd 1 ; End of memory pointer (bytes)
@@ -130,22 +143,11 @@ ClustPerMoby resd 1 ; Clusters per 64K
ClustSize resd 1 ; Bytes/cluster
KernelName resb 12 ; Mangled name for kernel
; (note the spare byte after!)
-RootDir equ $ ; Location of root directory
-RootDir1 resw 1
-RootDir2 resw 1
-DataArea equ $ ; Location of data area
-DataArea1 resw 1
-DataArea2 resw 1
FBytes equ $ ; Used by open/getc
FBytes1 resw 1
FBytes2 resw 1
-RootDirSize resw 1 ; Root dir size in sectors
-DirScanCtr resw 1 ; Used while searching directory
DirBlocksLeft resw 1 ; Ditto
-EndofDirSec resw 1 ; = trackbuf+bsBytesPerSec-31
RunLinClust resw 1 ; Cluster # for LDLINUX.SYS
-SecPerClust resw 1 ; Same as bsSecPerClust, but a word
-NextCluster resw 1 ; Pointer to "nextcluster" routine
BufSafe resw 1 ; Clusters we can load into trackbuf
BufSafeSec resw 1 ; = how many sectors?
BufSafeBytes resw 1 ; = how many bytes?
@@ -196,7 +198,15 @@ VGAFileMBuf resb 11 ; Mangled VGA image name
section .text
org 7C00h
-StackBuf equ $ ; Start the stack here (grow down - 4K)
+;
+; Some of the things that have to be saved very early are saved
+; "close" to the initial stack pointer offset, in order to
+; reduce the code size...
+;
+StackBuf equ $-32 ; Start the stack here (grow down - 4K)
+PartInfo equ StackBuf ; Saved partition table entry
+FloppyTable equ PartInfo+16 ; Floppy info table (must follow PartInfo)
+OrigFDCTabPtr equ StackBuf-4 ; The high dword on the stack
;
; Primary entry point. Tempting as though it may be, we can't put the
@@ -211,30 +221,49 @@ bootsec equ $
; loaded and ready for us
;
bsOemName db 'SYSLINUX' ; The SYS command sets this, so...
+;
+; These are the fields we actually care about. We end up expanding them
+; all to dword size early in the code, so generate labels for both
+; the expanded and unexpanded versions.
+;;
+%macro superb 1
+bx %+ %1 equ SuperInfo+($-superblock)*8+4
+bs %+ %1 equ $
+ zb 1
+%endmacro
+%macro superw 1
+bx %+ %1 equ SuperInfo+($-superblock)*8
+bs %+ %1 equ $
+ zw 1
+%endmacro
+%macro superd 1
+bx %+ %1 equ $ ; no expansion for dwords
+bs %+ %1 equ $
+ zd 1
+%endmacro
superblock equ $
-bsBytesPerSec zw 1
-bsSecPerClust zb 1
-bsResSectors zw 1
-bsFATs zb 1
-bsRootDirEnts zw 1
-bsSectors zw 1
-bsMedia zb 1
-bsFATsecs zw 1
-bsSecPerTrack zw 1
-bsHeads zw 1
-bsHiddenSecs equ $
-bsHidden1 zw 1
-bsHidden2 zw 1
-bsHugeSectors equ $
-bsHugeSec1 zw 1
-bsHugeSec2 zw 1
-bsDriveNumber zb 1
-bsReserved1 zb 1
-bsBootSignature zb 1 ; 29h if the following fields exist
-bsVolumeID zd 1
+ superw BytesPerSec
+ superb SecPerClust
+ superw ResSectors
+ superb FATs
+ superw RootDirEnts
+ superw Sectors
+ superb Media
+ superw FATsecs
+ superw SecPerTrack
+ superw Heads
+superinfo_size equ ($-superblock)-1 ; How much to expand
+ superd Hidden
+ superd HugeSectors
+ superb DriveNumber
+ superb Reserved1
+ superb BootSignature ; 29h if the following fields exist
+ superd VolumeID
bsVolumeLabel zb 11
-bsFileSysType zb 8 ; Must be FAT12 for this version
+bsFileSysType zb 8 ; Must be FAT12 or FAT16 for this version
superblock_len equ $-superblock
+
+SecPerClust equ bxSecPerClust
;
; Note we don't check the constraints above now; we did that at install
; time (we hope!)
@@ -248,52 +277,46 @@ start:
;
; Set up the stack
;
- xor cx,cx
- mov ss,cx
+ xor ax,ax
+ mov ss,ax
mov sp,StackBuf ; Just below BSS
- mov es,cx
+ mov es,ax
;
; DS:SI may contain a partition table entry. Preserve it for us.
;
- mov cl,8 ; Save partition info (CH == 0)
- mov di,PartInfo
+ mov cx,8 ; Save partition info
+ mov di,sp
rep movsw
+
+ mov ds,ax ; Now we can initialize DS...
+
+ mov [di+bsDriveNumber-FloppyTable],dl
+ and dl,dl ; If floppy disk (00-7F), assume no
+ js harddisk ; partition table
;
; Now sautee the BIOS floppy info block to that it will support decent-
; size transfers; the floppy block is 11 bytes and is stored in the
; INT 1Eh vector (brilliant waste of resources, eh?)
;
; Of course, if BIOSes had been properly programmed, we wouldn't have
-; had to waste precious boot sector space with this code.
-;
-; This code no longer fits. Hope that noone really needs it anymore.
-; (If so, it needs serious updating.) In fact, some indications is that
-; this code does more harm than good with all the new kinds of drives and
-; media.
+; had to waste precious space with this code.
;
-%ifdef SUPPORT_REALLY_BROKEN_BIOSES
- lds si,[ss:fdctab] ; DS:SI -> original
- push ds ; Save on stack in case
- push si ; we have to bail
- push bx
- mov cx,6 ; 12 bytes
- mov di,floppy_table
- push di
- cld
- rep movsw ; Faster to move words
- pop di
- mov ds,ax ; Now we can point DS to here, too
+ mov bx,fdctab
+ lfs si,[bx] ; FS:SI -> original fdctab
+ push fs ; Save on stack in case we need to bail
+ push si
+ mov cl,6 ; 12 bytes (CX == 0)
+ ; es:di -> FloppyTable already
+ ; This should be safe to do now, interrupts are off...
+ mov [bx],di ; FloppyTable
+ mov [bx+2],ax ; Segment 0
+ fs rep movsw ; Faster to move words
mov cl,[bsSecPerTrack] ; Patch the sector count
- mov [di+4],cl
- mov [fdctab+2],ax ; Segment 0
- mov [fdctab],di ; offset floppy_block
-%else
- mov ds,cx ; CX == 0
-%endif
-;
-; Ready to enable interrupts, captain
-;
- sti
+ mov [di-8],cl
+ ; AX == 0 here
+ int 13h ; Some BIOSes need this
+
+ jmp short not_harddisk
;
; The drive number and possibly partition information was passed to us
; by the BIOS or previous boot loader (MBR). Current "best practice" is to
@@ -303,15 +326,12 @@ start:
;
; Note: di points to beyond the end of PartInfo
;
- mov [bsDriveNumber],dl
- test dl,80h ; If floppy disk (00-7F), assume no
- jz not_harddisk ; partition table
- test byte [di-16],7Fh ; Sanity check: "active flag" should
- jnz no_partition ; be 00 or 80
- lea si,[di-8] ; Partition offset (dword)
- mov di,bsHidden1
- mov cl,2 ; CH == 0
- rep movsw
+harddisk:
+; This sanity check doesn't fit anymore...
+; test byte [di-16],7Fh ; Sanity check: "active flag" should
+; jnz no_partition ; be 00 or 80
+ mov eax,[di-8] ; Partition offset (dword)
+ mov [bsHidden],eax
no_partition:
;
; Get disk drive parameters (don't trust the superblock.) Don't do this for
@@ -325,69 +345,86 @@ no_partition:
jc no_driveparm
and ah,ah
jnz no_driveparm
- inc dh ; Contains # of heads - 1
- mov [bsHeads],dh
+ shr dx,8
+ inc dx ; Contains # of heads - 1
+ mov [bsHeads],dx
and cx,3fh
mov [bsSecPerTrack],cx
no_driveparm:
not_harddisk:
;
+; Ready to enable interrupts, captain
+;
+ sti
+;
+; Insane hack to expand the superblock to dwords
+;
+expand_super:
+ xor eax,eax
+ mov es,ax ; INT 13:08 destroys ES
+ mov si,superblock
+ mov di,SuperInfo
+ mov cl,superinfo_size ; CH == 0
+.loop:
+ lodsw
+ dec si
+ stosd ; Store expanded word
+ xor ah,ah
+ stosd ; Store expanded byte
+ loop .loop
+
+;
; Now we have to do some arithmetric to figure out where things are located.
; If Micro$oft had had brains they would already have done this for us,
; and stored it in the superblock at format time, but here we go,
; wasting precious boot sector space again...
;
+%define Z di-superinfo_size*8-SuperInfo
debugentrypt:
- xor ax,ax ; INT 13:08 destroys ES
- mov es,ax
- mov al,[bsFATs] ; Number of FATs (AH == 0)
- mul word [bsFATsecs] ; Get the size of the FAT area
- add ax,[bsHidden1] ; Add hidden sectors
- adc dx,[bsHidden2]
- add ax,[bsResSectors] ; And reserved sectors
- adc dx,byte 0
-
- mov [RootDir1],ax ; Location of root directory
- mov [RootDir2],dx
- mov [DataArea1],ax
- mov [DataArea2],dx
- push ax
- push dx
-
- mov ax,32 ; Size of a directory entry
- mul word [bsRootDirEnts]
- mov bx,[bsBytesPerSec]
+ mov ax,[bxFATs] ; Number of FATs (eax<31:16> == 0)
+ mov edx,[Z+bxFATsecs] ; Sectors/FAT
+ mul edx ; Get the size of the FAT area
+ ; edx <- 0
+ add eax,[bxHidden] ; Add hidden sectors
+ add eax,[Z+bxResSectors] ; And reserved sectors
+
+ mov [RootDir],eax ; Location of root directory
+ mov [DataArea],eax ; First data sector
+ push eax
+
+ mov eax,[Z+bxRootDirEnts]
+ shl ax,5 ; Size of a directory entry
+ mov bx,[Z+bxBytesPerSec]
add ax,bx ; Round up, not down
dec ax
div bx ; Now we have the size of the root dir
mov [RootDirSize],ax
mov [DirScanCtr],ax
add bx,trackbuf-31
- mov [EndofDirSec],bx ; End of a single directory sector
-
- add [DataArea1],ax
- adc word [DataArea2],byte 0
+ mov [Z+EndofDirSec],bx ; End of a single directory sector
+ add [Z+DataArea],eax
+ pop eax ; Reload root directory starting point
- pop dx ; Reload root directory starting point
- pop ax
;
; Now the fun begins. We have to search the root directory for
; LDLINUX.SYS and load the first sector, so we have a little more
; space to have fun with. Then we can go chasing through the FAT.
; Joy!!
;
-sd_nextsec: push ax
- push dx
+sd_nextsec: push eax
mov bx,trackbuf
push bx
call getonesec
pop si
-sd_nextentry: cmp byte [si],0 ; Directory high water mark
+sd_nextentry: mov cx,11
+ cmp [si],ch ; Directory high water mark
je kaboom
- test byte [si+11],18h ; Must be a file
- jnz sd_not_file
+; This no longer fits... since we'd be dead anyway if there
+; was a nonfile named LDLINUX.SYS on the disk, it shouldn't
+; matter...
+; test byte [si+11],18h ; Must be a file
+; jnz sd_not_file
mov di,ldlinux_name
- mov cx,11
push si
repe cmpsb
pop si
@@ -395,10 +432,8 @@ sd_nextentry: cmp byte [si],0 ; Directory high water mark
sd_not_file: add si,byte 32 ; Distance to next
cmp si,[EndofDirSec]
jb sd_nextentry
- pop dx
- pop ax
- add ax,byte 1
- adc dx,byte 0
+ pop eax
+ inc eax
dec word [DirScanCtr]
jnz sd_nextsec
;
@@ -407,8 +442,9 @@ sd_not_file: add si,byte 32 ; Distance to next
kaboom:
xor si,si
mov ss,si
- mov sp,StackBuf ; Reset stack
+ mov sp,StackBuf-4 ; Reset stack
mov ds,si ; Reset data segment
+ pop dword [fdctab] ; Restore FDC table
.patch: mov si,bailmsg
call writestr ; Returns with AL = 0
cbw ; AH <- 0
@@ -422,16 +458,14 @@ kaboom:
;
found_it: ; Note: we actually leave two words on the stack here
; (who cares?)
- xor ax,ax
- mov al,[bsSecPerClust]
+ mov eax,[bxSecPerClust]
mov bp,ax ; Load an entire cluster
- mov bx,[si+26] ; First cluster
+ movzx ebx,word [si+26] ; First cluster
mov [RunLinClust],bx ; Save for later use
dec bx ; First cluster is "cluster 2"
dec bx
- mul bx
- add ax,[DataArea1]
- adc dx,[DataArea2]
+ mul ebx
+ add eax,[DataArea]
mov bx,ldlinux_sys
call getlinsec
mov si,bs_magic
@@ -441,41 +475,32 @@ found_it: ; Note: we actually leave two words on the stack here
jne kaboom ; matches LDLINUX.SYS
;
; Done! Jump to the entry point!
-;
-; Note that some BIOSes are buggy and run the boot sector at 07C0:0000
-; instead of 0000:7C00 and the like. We don't want to add anything
-; more to the boot sector, so it is written to not assume a fixed
-; value in CS, but we don't want to deal with that anymore from now
-; on.
;
- jmp 0:ldlinux_ent
-
+ jmp ldlinux_ent
;
;
; writestr: write a null-terminated string to the console
;
writestr:
-wstr_1: lodsb
+.loop: lodsb
and al,al
- jz return
+ jz .return
mov ah,0Eh ; Write to screen as TTY
mov bx,0007h ; White on black, current page
int 10h
- jmp short wstr_1
+ jmp short .loop
+.return: ret
+
;
-; disk_error: decrement the retry count and bail if zero
+; disk_error: decrement the retry count and bail if zero.
+; This gets patched once we have more space to try to
+; optimize transfer sizes on broken machines.
;
disk_error: dec si ; SI holds the disk retry counter
jz kaboom
- pop bx ; <I>
- pop cx ; <H>
- pop dx ; <G>
- pop ax ; <F> (AH = 0)
- mov al,1 ; Once we fail, only transfer 1 sector
+ ; End of patched "call" instruction!
jmp short disk_try_again
-return: ret
-
;
; getonesec: like getlinsec, but pre-sets the count to 1
;
@@ -485,7 +510,7 @@ getonesec:
;
; getlinsec: load a sequence of BP floppy sector given by the linear sector
-; number in DX:AX into the buffer at ES:BX. We try to optimize
+; number in EAX into the buffer at ES:BX. We try to optimize
; by loading up to a whole track at a time, but the user
; is responsible for not crossing a 64K boundary.
; (Yes, BP is weird for a count, but it was available...)
@@ -497,28 +522,25 @@ getonesec:
; mov bp,1 ; nop ... (BD 01 00 90 90...) when installing with
; the -s option.
;
+; This routine assumes CS == DS.
+;
; Stylistic note: use "xchg" instead of "mov" when the source is a register
; that is dead from that point; this saves space. However, please keep
; the order to dst,src to keep things sane.
;
getlinsec:
- mov si,[bsSecPerTrack]
+ mov esi,[bxSecPerTrack]
;
; Dividing by sectors to get (track,sector): we may have
- ; up to 2^18 tracks, so we need to do this in two steps
- ; to produce a 32-bit quotient.
+ ; up to 2^18 tracks, so we need to use 32-bit arithmetric.
;
- xchg cx,ax ; CX <- LSW of LBA
- xchg ax,dx
- xor dx,dx ; DX:AX now == MSW of LBA
- div si ; Obtain MSW of track #
- xchg ax,cx ; Remainder -> MSW of new dividend
- ; LSW of LBA -> LSW of new dividend
- ; Quotient -> MSW of track #
- div si ; Obtain LSW of track #, remainder
- xchg cx,dx ; CX <- Sector index (0-based)
- ; DX <- MSW of track #
- div word [bsHeads] ; Convert track to head/cyl
+ xor edx,edx ; Zero-extend LBA to 64 bits
+ div esi
+ xor cx,cx
+ xchg cx,dx ; CX <- sector index (0-based)
+ ; EDX <- 0
+ ; eax = track #
+ div dword [bxHeads] ; Convert track to head/cyl
;
; Now we have AX = cyl, DX = head, CX = sector (0-based),
; BP = sectors to transfer, SI = bsSecPerTrack,
@@ -527,23 +549,25 @@ getlinsec:
gls_nextchunk: push si ; <A> bsSecPerTrack
push bp ; <B> Sectors to transfer
+ ; Important - this gets patched with a call. The call
+ ; assumes cx, si and bp are set up, and can modify bp
+ ; and destroy si. Until we have the space to do so,
+ ; transfer one sector at a time.
+gls_set_size:
__BEGIN_STUPID_PATCH_AREA:
- sub si,cx ; Sectors left on track
- cmp bp,si
- jna gls_lastchunk
- mov bp,si ; No more than a trackful, please!
+ mov bp,1 ; 3 bytes, same as a call insn
__END_STUPID_PATCH_AREA:
-gls_lastchunk:
+
push ax ; <C> Cylinder #
push dx ; <D> Head #
push cx ; <E> Sector #
- mov cl,6 ; Because IBM was STOOPID
- shl ah,cl ; and thought 8 bits were enough
+ shl ah,6 ; Because IBM was STOOPID
+ ; and thought 8 bits were enough
; then thought 10 bits were enough...
pop cx ; <E> Sector #
push cx ; <E> Sector #
- inc cx ; Sector numbers are 1-based
+ inc cx ; Sector numbers are 1-based, sigh
or cl,ah
mov ch,al
mov dh,dl
@@ -555,24 +579,16 @@ gls_lastchunk:
; Do the disk transfer... save the registers in case we fail :(
;
disk_try_again:
- push ax ; <F> Number of sectors we're transferring
+ pusha ; <F>
mov ah,02h ; READ DISK
- push dx ; <G>
- push cx ; <H>
- push bx ; <I>
- push si ; <J>
int 13h
- pop si ; <J>
+ popa ; <F>
jc disk_error
;
; Disk access successful
;
- pop bx ; <I> Buffer location
- pop ax ; <H> No longer needed
- pop ax ; <G> No longer needed
- pop di ; <F> Sector transferred count
pop cx ; <E> Sector #
- mov ax,di ; Reduce sector left count
+ mov di,ax ; Reduce sector left count
mul word [bsBytesPerSec] ; Figure out how much to advance ptr
add bx,ax ; Update buffer location
pop dx ; <D> Head #
@@ -580,7 +596,7 @@ disk_try_again:
pop bp ; <B> Sectors left to transfer
pop si ; <A> Number of sectors/track
sub bp,di ; Reduce with # of sectors just read
- jz return ; Done!
+ jz writestr.return ; Done!
add cx,di
cmp cx,si
jb gls_nextchunk
@@ -596,6 +612,7 @@ bailmsg: db 'Boot failed', 0Dh, 0Ah, 0
bs_checkpt equ $ ; Must be <= 7DEFh
+%if 1
bs_checkpt_off equ ($-$$)
%ifndef DEPEND
%if bs_checkpt_off > 1EFh
@@ -604,6 +621,7 @@ bs_checkpt_off equ ($-$$)
%endif
zb 1EFh-($-$$)
+%endif
bs_magic equ $ ; From here to the magic_len equ
; must match ldlinux_magic
ldlinux_name: db 'LDLINUX SYS' ; Looks like this in the root dir
@@ -628,9 +646,26 @@ ldlinux_magic db 'LDLINUX SYS'
dd HEXDATE
dw 0AA55h
- align 4
+;
+; This area is possibly patched by the installer. It is located
+; immediately after the EOF + LDLINUX SYS + 4 bytes + 55 AA + alignment,
+; so we can find it algorithmically.
+;
+ alignb 4
+MaxTransfer dw 00FFh ; Absolutely maximum transfer size
+ align 4
ldlinux_ent:
+;
+; Note that some BIOSes are buggy and run the boot sector at 07C0:0000
+; instead of 0000:7C00 and the like. We don't want to add anything
+; more to the boot sector, so it is written to not assume a fixed
+; value in CS, but we don't want to deal with that anymore from now
+; on.
+;
+ jmp 0:.next
+.next:
+
;
; Tell the user we got this far
;
@@ -641,22 +676,22 @@ ldlinux_ent:
; We can really only rely on a single sector having been loaded. Hence
; we should load the FAT into RAM and start chasing pointers...
;
- mov dx,1 ; 64K
xor ax,ax
- div word [bsBytesPerSec] ; sectors/64K
+ cwd
+ inc dx ; DX:AX <- 64K
+ div word [bxBytesPerSec] ; sectors/64K
mov si,ax
push es
mov bx,fat_seg ; Load into fat_seg:0000
mov es,bx
- mov ax,[bsHidden1] ; Hidden sectors
- mov dx,[bsHidden2]
- add ax,[bsResSectors] ; plus reserved sectors = FAT
- adc dx,byte 0
- mov cx,[bsFATsecs] ; Sectors/FAT
+ mov eax,[bsHidden] ; Hidden sectors
+ add edx,[bxResSectors]
+ add eax,edx
+ mov ecx,[bxFATsecs] ; Sectors/FAT
fat_load_loop:
- mov bp,cx
+ mov ebp,ecx ; Make sure high EBP = 0
cmp bp,si
jna fat_load
mov bp,si ; A full 64K moby
@@ -665,8 +700,7 @@ fat_load:
call getlinsecsr
sub cx,bp
jz fat_load_done ; Last moby?
- add ax,bp ; Advance sector count
- adc dx,byte 0
+ add eax,ebp ; Advance sector count
mov bx,es ; Next 64K moby
add bx,1000h
mov es,bx
@@ -678,20 +712,17 @@ fat_load_done:
; Also figure out how many clusters will fit in an 8K buffer, and how
; many sectors and bytes that is
;
- mov di,[bsBytesPerSec] ; Used a lot below
-
- movzx eax,byte [bsSecPerClust] ; We do this in the boot
- ; sector, too, but there
- mov [SecPerClust],ax ; wasn't space to save it
- mov si,ax ; Also used a lot...
+ mov edi,[bxBytesPerSec] ; Used a lot below
+ mov eax,[SecPerClust]
+ mov si,ax ; Also used a lot
mul di
mov [ClustSize],eax ; Bytes/cluster
mov bx,ax
- mov ax,trackbufsize
- xor dx,dx
+ mov ax,trackbufsize ; High bit 0
+ cwd
div bx
mov [BufSafe],ax ; # of cluster in trackbuf
- mul word [SecPerClust]
+ mul si
mov [BufSafeSec],ax
mul di
mov [BufSafeBytes],ax
@@ -700,40 +731,29 @@ fat_load_done:
;
; FAT12 or FAT16? This computation is fscking ridiculous...
;
- xor dx,dx
- xor cx,cx
- mov ax,[bsSectors]
+ mov eax,[bxSectors]
and ax,ax
jnz have_secs
- mov ax,[bsHugeSectors]
- mov dx,[bsHugeSectors+2]
-have_secs: sub ax,[bsResSectors]
- sbb dx,byte 0
- mov cl,[bsFATs]
-sec_fat_loop: sub ax,[bsFATsecs]
- sbb dx,byte 0
- loop sec_fat_loop
- push ax
- push dx
- mov ax,[bsRootDirEnts]
- mov bx,32 ; Smaller than shift since we
- mul bx ; need the doubleword product
- add ax,di
- adc dx,byte 0
- sub ax,byte 1
- sbb dx,byte 0
- div di
- mov bx,ax
- pop dx
- pop ax
- sub ax,bx
- sbb dx,byte 0
- div si
- cmp ax,4086 ; Right value?
- mov ax,nextcluster_fat16
- ja have_fat_type
-have_fat12: mov ax,nextcluster_fat12
-have_fat_type: mov word [NextCluster],ax
+ mov eax,[bsHugeSectors]
+have_secs: add eax,[bsHidden] ; These are not included
+ sub eax,[RootDir] ; Start of root directory
+ movzx ebx,word [RootDirSize]
+ sub eax,ebx ; Subtract root directory size
+ xor edx,edx
+ div esi ; Convert to clusters
+ cmp ax,4086 ; FAT12 limit
+ jna is_fat12
+ ; Patch the jump
+ mov byte [nextcluster+1],nextcluster_fat16-(nextcluster+2)
+is_fat12:
+
+;
+; Patch gls_set_size so we can transfer more than one sector at a time.
+;
+ mov byte [gls_set_size],0xe8 ; E8 = CALL NEAR
+ mov word [gls_set_size+1],do_gls_set_size-(gls_set_size+3)
+ mov byte [disk_error],0xe8
+ mov word [disk_error+1],do_disk_error-(disk_error+3)
;
; Now we read the rest of LDLINUX.SYS. Don't bother loading the first
@@ -744,7 +764,7 @@ load_rest:
mov bx,ldlinux_sys
add bx,cx
mov si,[RunLinClust]
- call [NextCluster]
+ call nextcluster
xor dx,dx
mov ax,ldlinux_len-1 ; To be on the safe side
add ax,cx
@@ -775,19 +795,18 @@ all_read_jmp:
;
; 386 check
getfssec:
-getfragment: xor bp,bp ; Fragment sector count
- mov ax,si ; Get sector address
+getfragment: xor ebp,ebp ; Fragment sector count
+ movzx eax,si ; Get sector address
dec ax ; Convert to 0-based
dec ax
- mul word [SecPerClust]
- add ax,[DataArea1]
- adc dx,[DataArea2]
+ mul dword [SecPerClust]
+ add eax,[DataArea]
getseccnt: ; See if we can read > 1 clust
add bp,[SecPerClust]
dec cx ; Reduce clusters left to find
- mov di,si ; Predict next cluster
- inc di
- call [NextCluster]
+ lea di,[si+1]
+ call nextcluster
+ cmc
jc gfs_eof ; At EOF?
jcxz endfragment ; Or was it the last we wanted?
cmp si,di ; Is file continuous?
@@ -797,31 +816,24 @@ gfs_eof: pushf ; Remember EOF or not
push si
push cx
gfs_getchunk:
- push ax
- push dx
+ push eax
mov ax,es ; Check for 64K boundaries.
- mov cl,4
- shl ax,cl
+ shl ax,4
add ax,bx
xor dx,dx
neg ax
- jnz gfs_partseg
- inc dx ; Full 64K segment
-gfs_partseg:
+ setz dl ; DX <- 1 if full 64K segment
div word [bsBytesPerSec] ; How many sectors fit?
mov si,bp
sub si,ax ; Compute remaining sectors
jbe gfs_lastchunk
mov bp,ax
- pop dx
- pop ax
+ pop eax
call getlinsecsr
- add ax,bp
- adc dx,byte 0
+ add eax,ebp ; EBP<31:16> == 0
mov bp,si ; Remaining sector count
jmp short gfs_getchunk
-gfs_lastchunk: pop dx
- pop ax
+gfs_lastchunk: pop eax
call getlinsec
pop cx
pop si
@@ -833,51 +845,33 @@ gfs_return: ret
;
; getlinsecsr: save registers, call getlinsec, restore registers
;
-getlinsecsr: push ax
- push dx
- push cx
- push bp
- push si
- push di
+getlinsecsr: pushad
call getlinsec
- pop di
- pop si
- pop bp
- pop cx
- pop dx
- pop ax
+ popad
ret
;
; nextcluster: Advance a cluster pointer in SI to the next cluster
-; pointed at in the FAT tables (note: FAT12 assumed)
-; Sets CF on return if end of file.
-;
-; The variable NextCluster gets set to the appropriate
-; value here.
+; pointed at in the FAT tables. CF=0 on return if end of file.
;
+nextcluster:
+ jmp short nextcluster_fat12 ; This gets patched
+
nextcluster_fat12:
- push ax
+ push bx
push ds
- mov ax,fat_seg
- mov ds,ax
- mov ax,si ; Multiply by 3/2
- shr ax,1
- pushf ; CF now set if odd
- add si,ax
- mov si,[si]
- popf
+ mov bx,fat_seg
+ mov ds,bx
+ mov bx,si ; Multiply by 3/2
+ shr bx,1 ; CF now set if odd
+ mov si,[si+bx]
jnc nc_even
- shr si,1 ; Needed for odd only
- shr si,1
- shr si,1
- shr si,1
+ shr si,4 ; Needed for odd only
nc_even:
and si,0FFFh
cmp si,0FF0h ; Clears CF if at end of file
- cmc ; But we want it SET...
pop ds
- pop ax
+ pop bx
nc_return: ret
;
@@ -894,10 +888,47 @@ nextcluster_fat16:
.seg0: mov ds,ax
mov si,[si]
cmp si,0FFF0h
- cmc
pop ds
pop ax
ret
+
+;
+; Routine that controls how much we can transfer in one chunk. Called
+; from gls_set_size in getlinsec.
+;
+do_gls_set_size:
+ sub si,cx ; Sectors left on track
+ cmp bp,si
+ jna .lastchunk
+ mov bp,si ; No more than a trackful, please!
+.lastchunk:
+ cmp bp,[MaxTransfer] ; Absolute maximum transfer size
+ jna .oktransfer
+ mov bp,[MaxTransfer]
+.oktransfer:
+ ret
+
+;
+; This routine captures disk errors, and tries to decide if it is
+; time to reduce the transfer size.
+;
+do_disk_error:
+ dec si ; Decrement the retry counter
+ jz kaboom ; If expired, croak
+ cmp si,2 ; If only 2 attempts left
+ ja .nodanger
+ mov al,1 ; Drop transfer size to 1
+ jmp short .setsize
+.nodanger:
+ cmp si,retry_count-2
+ ja .again ; First time, just try again
+ shr al,1 ; Otherwise, try to reduce
+ adc al,0 ; the max transfer size, but not to 0
+.setsize:
+ mov [MaxTransfer],al
+.again:
+ ret
+
;
; Debug routine
;
@@ -951,8 +982,8 @@ all_read:
; Now, everything is "up and running"... patch kaboom for more
; verbosity and using the full screen system
;
- mov byte [kaboom.patch],0e9h ; JMP NEAR
- mov word [kaboom.patch+1],kaboom2-(kaboom.patch+3)
+ ; E9 = JMP NEAR
+ mov dword [kaboom.patch],0e9h+((kaboom2-(kaboom.patch+3)) << 8)
;
; Compute some parameters that depend on cluster size
@@ -983,7 +1014,7 @@ all_read:
mov di,KbdMap ; Default keymap 1:1
xor al,al
- mov cx,256
+ inc ch ; CX <- 256
mkkeymap: stosb
inc al
loop mkkeymap
@@ -1396,10 +1427,9 @@ searchdir:
mov [DirScanCtr],ax
mov ax,[RootDirSize]
mov [DirBlocksLeft],ax
- mov ax,[RootDir1]
- mov dx,[RootDir2]
+ mov eax,[RootDir]
scan_group:
- mov bp,[DirBlocksLeft]
+ movzx ebp,word [DirBlocksLeft]
and bp,bp
jz dir_return
cmp bp,[BufSafeSec]
@@ -1407,24 +1437,14 @@ scan_group:
mov bp,[BufSafeSec]
load_last:
sub [DirBlocksLeft],bp
- push ax
- push dx
+ push eax
mov ax,[bsBytesPerSec]
mul bp
add ax,trackbuf-31
mov [EndofDirSec],ax ; End of loaded
- pop dx
- pop ax
- push bp ; Save number of sectors
- push ax ; Save present location
- push dx
- push di ; Save name
+ pop eax
mov bx,trackbuf
- call getlinsec
- pop di
- pop dx
- pop ax
- pop bp
+ call getlinsecsr
mov si,trackbuf
dir_test_name: cmp byte [si],0 ; Directory high water mark
je dir_return ; Failed
@@ -1442,8 +1462,7 @@ dir_not_this: add si,byte 32
jz dir_return ; Out of it...
cmp si,[EndofDirSec]
jb dir_test_name
- add ax,bp ; Increment linear sector number
- adc dx,byte 0
+ add eax,ebp ; Increment linear sector number
jmp short scan_group
dir_success:
mov ax,[si+28] ; Length of file
diff --git a/macros.inc b/macros.inc
index 3610ff54..f1cb66df 100644
--- a/macros.inc
+++ b/macros.inc
@@ -35,57 +35,6 @@
%endif
;
-; For our convenience: define macros for jump-over-unconditinal jumps
-;
-%macro jmpz 1
- jnz %%skip
- jmp %1
-%%skip:
-%endmacro
-
-%macro jmpnz 1
- jz %%skip
- jmp %1
-%%skip:
-%endmacro
-
-%macro jmpe 1
- jne %%skip
- jmp %1
-%%skip:
-%endmacro
-
-%macro jmpne 1
- je %%skip
- jmp %1
-%%skip:
-%endmacro
-
-%macro jmpc 1
- jnc %%skip
- jmp %1
-%%skip:
-%endmacro
-
-%macro jmpnc 1
- jc %%skip
- jmp %1
-%%skip:
-%endmacro
-
-%macro jmpb 1
- jnb %%skip
- jmp %1
-%%skip:
-%endmacro
-
-%macro jmpnb 1
- jb %%skip
- jmp %1
-%%skip:
-%endmacro
-
-;
; Macros similar to res[bwd], but which works in the code segment (after
; section .text)
;
diff --git a/runkernel.inc b/runkernel.inc
index 25e128c9..b87c9210 100644
--- a/runkernel.inc
+++ b/runkernel.inc
@@ -510,25 +510,18 @@ in_proper_place:
jne root_not_floppy
mov word [es:bs_rootdev],0200h
root_not_floppy:
+
;
; Copy the disk table to high memory, then re-initialize the floppy
; controller
;
-; This needs to be moved before the copy
-;
-%if 0
- push ds
- push bx
- lds si,[fdctab]
+%if IS_SYSLINUX
+ lgs si,[cs:fdctab]
mov di,linux_fdctab
- mov cx,3 ; 12 bytes
- push di
- rep movsd
- pop di
- mov [fdctab1],di ; Save new floppy tab pos
- mov [fdctab2],es
- pop bx
- pop ds
+ mov cx,6 ; 12 bytes
+ gs rep movsw
+ mov [cs:fdctab],word linux_fdctab ; Save new floppy tab pos
+ mov [cs:fdctab+2],es
%endif
;
; Linux wants the floppy motor shut off before starting the kernel,
diff --git a/syslinux.asm b/syslinux.asm
index ba23d20d..e104236a 100644
--- a/syslinux.asm
+++ b/syslinux.asm
@@ -440,12 +440,12 @@ die_common:
int 21h
;
-; This includes a small subroutine make_stupid to patch up the boot sector
-; in case we give the -s (stupid) option
+; Patch the code to make it "stupid"
;
-%ifndef DEPEND ; Generated file
-%include "stupid.gen"
-%endif
+make_stupid:
+ ; Only access one sector at a time
+ mov word [LDLinuxSYS+PATCH_OFFSET],1
+ ret
section .data
msg_error_sp: db 'ERROR $'
diff --git a/syslinux.c b/syslinux.c
index 106357fb..bc2dbd45 100644
--- a/syslinux.c
+++ b/syslinux.c
@@ -52,8 +52,6 @@ extern unsigned int bootsect_len;
extern unsigned char ldlinux[];
extern unsigned int ldlinux_len;
-extern void make_stupid(void); /* Patching routine for stupid mode */
-
char *program; /* Name of program */
char *device; /* Device to install to */
uid_t euid; /* Our current euid */
@@ -100,6 +98,28 @@ static u_int32_t get_32(unsigned char *p)
((u_int32_t)p[2] << 16) + ((u_int32_t)p[3] << 24);
}
+static void set_16(unsigned char *p, u_int16_t v)
+{
+ p[0] = (v & 0xff);
+ p[1] = ((v >> 8) & 0xff);
+}
+
+#if 0 /* Not needed */
+static void set_32(unsigned char *p, u_int32_t v)
+{
+ p[0] = (v & 0xff);
+ p[1] = ((v >> 8) & 0xff);
+ p[2] = ((v >> 16) & 0xff);
+ p[3] = ((v >> 24) & 0xff);
+}
+#endif
+
+/* Patch the code so that we're running in stupid mode */
+static void make_stupid(void)
+{
+ set_16(ldlinux+PATCH_OFFSET, 1); /* Access only one sector at a time */
+}
+
void usage(void)
{
fprintf(stderr, "Usage: %s [-sf] [-o offset] device\n", program);
diff --git a/version b/version
index bc8a6589..07cde984 100644
--- a/version
+++ b/version
@@ -1 +1 @@
-1.74
+1.75