Delete 16-bit COMBOOT support

16-bit COMBOOT files are no longer supported by Syslinux in 5.00 so
delete all references and change any 32-bit COMBOOT image references
to mention ELF instead.

Some of the COMBOOT stuff is still used internally so we can't nuke
core/comboot.inc yet, but that will disappear in a future release.

Signed-off-by: Matt Fleming <matt.fleming@intel.com>

Makefile

@@ -30,7 +30,7 @@ include $(MAKEDIR)/syslinux.mk
 # directories.
 #
 
-MODULES = memdisk/memdisk memdump/memdump.com modules/*.com \
+MODULES = memdisk/memdisk memdump/memdump.com \
 	com32/menu/*.c32 com32/modules/*.c32 com32/mboot/*.c32 \
 	com32/hdt/*.c32 com32/rosh/*.c32 com32/gfxboot/*.c32 \
 	com32/sysdump/*.c32 com32/lua/src/*.c32 com32/chain/*.c32 \
@@ -57,7 +57,7 @@ BOBJECTS = $(BTARGET) \
 # Note: libinstaller is both a BSUBDIR and an ISUBDIR.  It contains
 # files that depend only on the B phase, but may have to be regenerated
 # for "make installer".
-BSUBDIRS = codepage com32 lzo core memdisk modules mbr memdump gpxe sample \
+BSUBDIRS = codepage com32 lzo core memdisk mbr memdump gpxe sample \
 	   diag libinstaller dos win32 win64 dosutil
 ITARGET  =
 IOBJECTS = $(ITARGET) \

NEWS

@@ -25,6 +25,9 @@ Changes in 5.00:
 	* ldlinux: A new "PATH" directive was added to the ldlinux.c32
 	  config parser that specifies a colon-separated list of
 	  directories to search when attempting to load modules.
+	* ALL: Delete all references to/code for 16-bit COMBOOT files.
+	  COMBOOT files (.cbt and .com) are no longer supported under
+	  Syslinux.
 
 Changes in 4.06:
 	* Support for NTFS, by Paulo Alcantara.

README

@@ -7,7 +7,6 @@ See the files in the doc directory for documentation about SYSLINUX:
 	extlinux.txt	    - Documentation specific to EXTLINUX.
 	menu.txt	    - About the menu systems.
 	usbkey.txt	    - About using SYSLINUX on USB keys.
-	comboot.txt	    - About the extension API.
 	memdisk.txt         - Documentation about MEMDISK.
 
 Also see the files:

com32/elflink/ldlinux/execute.c

@@ -39,7 +39,6 @@ const struct image_types image_boot_types[] = {
     { "bss", IMAGE_TYPE_BSS },
     { "pxe", IMAGE_TYPE_PXE },
     { "fdimage", IMAGE_TYPE_FDIMAGE },
-    { "comboot", IMAGE_TYPE_COMBOOT },
     { "com32", IMAGE_TYPE_COM32 },
     { "config", IMAGE_TYPE_CONFIG },
     { NULL, 0 },

com32/elflink/ldlinux/ldlinux.c

@@ -21,8 +21,6 @@ struct file_ext {
 };
 
 static const struct file_ext file_extensions[] = {
-	{ ".com", IMAGE_TYPE_COMBOOT },
-	{ ".cbt", IMAGE_TYPE_COMBOOT },
 	{ ".c32", IMAGE_TYPE_COM32 },
 	{ ".img", IMAGE_TYPE_FDIMAGE },
 	{ ".bss", IMAGE_TYPE_BSS },

com32/include/menu.h

@@ -87,7 +87,6 @@ enum kernel_type {
     KT_BSS,			/* Boot sector with patch */
     KT_PXE,			/* PXE NBP */
     KT_FDIMAGE,			/* Floppy disk image */
-    KT_COMBOOT,			/* COMBOOT image */
     KT_COM32,			/* COM32 image */
     KT_CONFIG,			/* Configuration file */
 };

com32/include/syslinux/boot.h

@@ -61,7 +61,6 @@ extern const struct image_types image_boot_types[];
 #define IMAGE_TYPE_BSS		3
 #define IMAGE_TYPE_PXE		4
 #define IMAGE_TYPE_FDIMAGE	5
-#define IMAGE_TYPE_COMBOOT	6
 #define IMAGE_TYPE_COM32	7
 #define IMAGE_TYPE_CONFIG	8
 #define IMAGE_TYPE_LOCALBOOT	9

com32/sysdump/README

@@ -1,4 +1,4 @@
-This is a very simple COMBOOT program which can be used to dump memory
+This is a very simple COM32 program which can be used to dump memory
 regions over a serial port.  To use it, type on the SYSLINUX command
 line:
 

core/comboot.inc

@@ -114,7 +114,7 @@ DOSSaveVectors	resd 32
 
 comboot_vectors:
 		dw comboot_return	; INT 20 = exit
-		dw comboot_int21	; INT 21 = DOS-compatible system calls
+		dw comboot_err(21h)	; INT 21 = DOS-compatible system calls
 		dw comboot_int22	; INT 22 = native system calls
 		dw comboot_err(23h)	; INT 23 = DOS Ctrl-C handler
 		dw comboot_err(24h)	; INT 24 = DOS critical error handler
@@ -148,31 +148,6 @@ comboot_vectors:
 
 		section .text16
 
-; INT 21h: generic DOS system call
-comboot_int21:	sti
-		push ds
-		push es
-		push fs
-		push gs
-		pushad
-		cld
-		mov bp,cs
-		mov ds,bp
-		mov es,bp
-		mov bp,sp			; Set up stack frame
-
-		pm_call pm_adjust_screen	; The COMBOOT program might hav changed the screen
-
-		mov cx,int21_count
-		mov si,int21_table
-.again:		lodsb
-		cmp al,P_AH
-		lodsw
-		loopne .again
-		; The last function in the list is the
-		; "no such function" function
-		clc
-		call ax			; Call the invoked function
 comboot_resume:
 		mov bp,sp		; In case the function clobbers BP
 		setc P_FLAGSL		; Propagate CF->error
@@ -212,7 +187,7 @@ comboot_bogus_tail:
 		jmp kaboom
 
 ; Proper return vector
-; Note: this gets invoked both via INT 21h and directly via INT 20h.
+; Note: this gets invoked directly via INT 20h.
 ; We don't need to cld explicitly here, because comboot_exit does that
 ; when invoking RESET_STACK_AND_SEGS.
 comboot_return:
@@ -457,24 +432,6 @@ comapi_initadv:
 
 		section .data16
 
-%macro		int21 2
-		db %1
-		dw %2
-%endmacro
-
-int21_table:
-		int21	00h, comboot_return
-		int21	01h, comboot_getkey
-		int21	02h, comboot_writechr
-		int21	04h, comboot_writeserial
-		int21	08h, comboot_getkeynoecho
-		int21	09h, comboot_writestr
-		int21	0Bh, comboot_checkkey
-		int21	30h, comboot_checkver
-		int21	4Ch, comboot_return
-		int21	 -1, comboot_bad_int21
-int21_count	equ ($-int21_table)/3
-
 		alignz 2
 int22_table:
 		dw comapi_err		; 0000 unimplemented syscall