simplify track_int13 and some related code, and fix a few bugs in VBE support code.

ChangeLog

@@ -1,3 +1,21 @@
+2000-11-22  OKUJI Yoshinori  <okuji@gnu.org>
+
+	From Vesa Jaaskelainen <jaaskela@tietomyrsky.fi>:
+	* stage2/builtins.c (testvbe_func): Don't set the bit 14 of a
+	VBE mode number explicitly when calling get_vbe_mode_info.
+	(vbeprobe_func): Likewise.
+	
+2000-11-22  OKUJI Yoshinori  <okuji@gnu.org>
+
+	The code for the "INT 13H tracking technique" is somewhat
+	simplified.
+
+	* stage2/asm.S [!STAGE1_5] (track_int13): Don't replace an int13
+	handler with set_tf_int13_handler. Instead, track_int13 itself
+	emulates an int13 interrupt.
+	[!STAGE1_5] (set_tf_int13_handler): Removed.
+	[!STAGE1_5] (int1_handler): Use movzbw instead of xorb and movb.
+	
 2000-11-15  OKUJI Yoshinori  <okuji@gnu.org>
 
 	* acconfig.h (PRESET_MENU_STRING): New entry.

THANKS

@@ -57,3 +57,4 @@ Thierry DELHAISE <thierry.delhaise@delhaise.com>
 Thomas Schweikle <tschweikle@fiducia.de>
 Torsten Duwe <duwe@caldera.de>
 VaX#n8 <vax@linkdead.paranoia.com>
+Vesa Jaaskelainen <jaaskela@tietomyrsky.fi>

stage2/asm.S

@@ -288,16 +288,10 @@ ENTRY(track_int13)
 	pushl	%ebx
 	pushl	%edi
 
-	/* save the original int13 handler */
+	/* copy the original int13 handler segment:offset */
 	movl	$0x4c, %edi
-	movw	(%edi), %ax
+	movl	(%edi), %eax
-	movw	%ax, ABS(set_tf_int13_offset)
+	movl	%eax, track_int13_addr
-	movw	2(%edi), %ax
-	movw	%ax, ABS(set_tf_int13_segment)
-
-	/* save the new int13 handler */
-	movl	$ABS(set_tf_int13_handler), %eax
-	movl	%eax, (%edi)
 		
 	/* replace the int1 handler */
 	movl	$0x4, %edi
@@ -317,8 +311,25 @@ ENTRY(track_int13)
 	movw	$1, %cx
 	xorb	%dh, %dh
 
-	movw	$0x201, %ax
+	/* save FLAGS on the stack to emulate int13 */
-	int	$0x13
+	pushfw
+	
+	/* set the TF flag */
+	/* FIXME: this can be simplified not to use AX */
+	pushfw
+	popw	%ax
+	orw	$0x100, %ax
+	pushw	%ax
+	popfw
+
+	movw	$0x0201, %ax
+
+	.byte	0x9a		/* lcall */
+track_int13_addr:
+	.word	0		/* offset */
+	.word	0		/* segment */
+
+	/* TF is cleared here automatically */
 	
 	DATA32	call	EXT_C(real_to_prot)
 	.code32
@@ -327,13 +338,6 @@ ENTRY(track_int13)
 	movl	$0x4, %edi
 	popl	(%edi)
 
-	/* restore the int13 handler */
-	movl	$0x4c, %edi
-	movw	ABS(set_tf_int13_offset), %ax
-	movw	%ax, (%edi)
-	movw	ABS(set_tf_int13_segment), %ax
-	movw	%ax, 2(%edi)
-
 	popl	%edi
 	popl	%ebx
 	popl	%ebp
@@ -407,9 +411,8 @@ int1_handler:
 	jg	8f
 
 7:	/* immediate has a port */
-	xorb	%ah, %ah
 	lodsb	(%si), %al
-	movw	%ax, %dx
+	movzbw	%al, %dx
 	
 5:	/* %dx has a port */
 
@@ -447,37 +450,6 @@ int1_handler:
 
 	iret
 	
-
-/*
- * Just set the TF flag. This handler is necessary because any interrupt
- * call clears the flag automatically.
- *
- * Note: we need not to clear this flag after the tracking explicitly,
- * because iret restores the original FLAGS.
- */
-set_tf_int13_handler:
-	/* save %ax int the stack */
-	pushw	%ax
-	
-	/* set the TF flag */
-	pushf
-	popw	%ax
-	orw	$0x100, %ax
-	pushw	%ax
-	popf
-
-	/* restore %ax */
-	popw	%ax
-
-	/* simulate the interrupt call */
-	pushf
-	/* lcall */
-	.byte	0x9a
-set_tf_int13_offset:	.word	0
-set_tf_int13_segment:	.word	0
-
-	iret
-
 	.code32
 
 ENTRY(io_map)

stage2/builtins.c

@@ -4061,7 +4061,7 @@ testvbe_func (char *arg, int flags)
       return 0;
     }
 
-  if (get_vbe_mode_info (mode_number | (1 << 14), &mode) != 0x004F
+  if (get_vbe_mode_info (mode_number, &mode) != 0x004F
       || (mode.mode_attributes & 0x0091) != 0x0091)
     {
       grub_printf (" Mode 0x%x is not supported.\n", mode_number);
@@ -4303,7 +4303,7 @@ vbeprobe_func (char *arg, int flags)
     {
       struct vbe_mode mode;
       
-      if (get_vbe_mode_info (*mode_list | (1 << 14), &mode) != 0x004F)
+      if (get_vbe_mode_info (*mode_list, &mode) != 0x004F)
 	continue;
 
       /* Skip this, if this is not supported or linear frame buffer