Patch generator for the -s (stupid) option.

4 files changed, 101 insertions, 16 deletions

diff --git a/Makefile b/Makefile
index 70c758c6..a955254a 100644
--- a/Makefile
+++ b/Makefile
@@ -30,7 +30,7 @@ VERSION = $(shell cat version)
 SOURCES = ldlinux.asm syslinux.asm syslinux.c
 TARGETS = bootsect.bin ldlinux.sys syslinux.com syslinux
 DOCS    = COPYING NEWS README TODO syslinux.doc keytab-lilo.doc
-OTHER   = Makefile bin2c.pl now.pl keytab-lilo.pl version
+OTHER   = Makefile bin2c.pl now.pl genstupid.pl keytab-lilo.pl version
 
 all:	$(TARGETS)
 	ls -l $(TARGETS)
@@ -42,8 +42,9 @@ ifndef DATE
 DATE = $(shell perl now.pl)
 endif
 
-ldlinux.bin: ldlinux.asm
+ldlinux.bin: ldlinux.asm genstupid.pl
 	$(NASM) -f bin -dVERSION="'$(VERSION)'" -dDATE_STR="'$(DATE)'" -l ldlinux.lst -o ldlinux.bin ldlinux.asm
+	perl genstupid.pl < ldlinux.lst
 
 bootsect.bin: ldlinux.bin
 	dd if=ldlinux.bin of=bootsect.bin bs=512 count=1
@@ -51,7 +52,7 @@ bootsect.bin: ldlinux.bin
 ldlinux.sys: ldlinux.bin
 	dd if=ldlinux.bin of=ldlinux.sys  bs=512 skip=1
 
-syslinux.com: syslinux.asm bootsect.bin ldlinux.sys
+syslinux.com: syslinux.asm bootsect.bin ldlinux.sys stupid.inc
 	$(NASM) -f bin -l syslinux.lst -o syslinux.com syslinux.asm
 
 bootsect_bin.c: bootsect.bin bin2c.pl
@@ -60,14 +61,20 @@ bootsect_bin.c: bootsect.bin 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
+syslinux: syslinux.o bootsect_bin.o ldlinux_bin.o stupid.o
 	$(CC) $(LDFLAGS) -o syslinux syslinux.o bootsect_bin.o ldlinux_bin.o
 
+stupid.o: stupid.c
+
+stupid.c: ldlinux.asm
+
+stupid.inc: ldlinux.asm
+
 install: all
 	install -c syslinux $(BINDIR)
 
 tidy:
-	rm -f ldlinux.bin *.lst *.o *_bin.c
+	rm -f ldlinux.bin *.lst *.o *_bin.c stupid.*
 
 clean: tidy
 	rm -f $(TARGETS)
diff --git a/genstupid.pl b/genstupid.pl
new file mode 100644
index 00000000..2001268e
--- /dev/null
+++ b/genstupid.pl
@@ -0,0 +1,77 @@
+#ident "$Id$"
+## -----------------------------------------------------------------------
+##   
+##   Copyright 1998 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.inc") || 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 bc0c78a8..46631b11 100644
--- a/ldlinux.asm
+++ b/ldlinux.asm
@@ -638,8 +638,9 @@ getonesec:
 ;	     On return, BX points to the first byte after the transferred
 ;	     block.
 ;
-;	     When compiling with the STUPID option, this is replaced by a
-;	     routine which loads one sector at a time.
+;	     The "stupid patch area" gets replaced by the code
+;	     mov bp,1 ; nop ... (BD 01 00 90 90...) when installing with
+;	     the -s option.
 ;
 getlinsec:
 		mov si,[bsSecPerTrack]
@@ -654,20 +655,14 @@ getlinsec:
 		;
 gls_nextchunk:	push si			; <A> bsSecPerTrack
 		push bp			; <B> Sectors to transfer
-%ifdef STUPID
-		mov bp,1
-		nop			; Minimize size of patch
-		nop
-		nop
-		nop
-		nop
-%else
+
+__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!
+__END_STUPID_PATCH_AREA:
 gls_lastchunk:	
-%endif
 		push ax			; <C> Cylinder #
 		push dx			; <D> Head #
 		push bp			; <E> Number of sectors we're transferring
diff --git a/syslinux.asm b/syslinux.asm
index 40820847..0b28774b 100644
--- a/syslinux.asm
+++ b/syslinux.asm
@@ -253,6 +253,12 @@ die:
 		mov ax,4C01h			; Exit error status
 		int 21h
 
+;
+; This includes a small subroutine make_stupid to patch up the boot sector
+; in case we give the -s (stupid) option
+;
+		%include "stupid.inc"
+
 		section .data
 msg_error:		db 'ERROR: $'
 msg_filesystem_err:	db 'Filesystem not found on disk', 0Dh, 0Ah, '$'