PERFORCE change 41598 for review

[John Baldwin]

http://perforce.freebsd.org/chv.cgi?CH=41598

Change 41598 by jhb at jhb_laptop on 2003/11/06 13:44:50

	Revert the BTX changes in this branch.

Affected files ...

.. //depot/projects/smpng/sys/boot/i386/btx/btx/btx.s#7 edit

Differences ...

==== //depot/projects/smpng/sys/boot/i386/btx/btx/btx.s#7 (text+ko) ====

@@ -208,7 +208,7 @@
 ifdef(`PAGING',`
 		or $0x80000001,%eax             #  mode and enable paging
 ',`
-		inc %ax				#  mode
+		or $0x01,%eax			#  mode
 ')
 		mov %eax,%cr0			#  
 		ljmp $SEL_SCODE,$init.8		# To 32-bit code
@@ -493,7 +493,9 @@
 		je v86wrmsr			# Yes
 		cmpb $0x32,(%esi)		# Is it a RDMSR?
 		je v86rdmsr			# Yes
-		cmpb $0x20,(%esi)		# Is this a MOV reg,CRx?
+		cmpb $0x20,(%esi)		# Is this a
+		jne v86mon.4			#  MOV EAX,CR0
+		cmpb $0xc0,0x1(%esi)		#  instruction?
 		je v86mov			# Yes
 v86mon.4:	cmpb $0xfa,%al			# CLI?
 		je v86cli			# Yes
@@ -525,24 +527,10 @@
 		leal 0x8(%esp,1),%esp		# Discard int no, error
 		iret				# To V86 mode
 #
-# Emulate MOV reg,CRx.
+# Emulate MOV EAX,CR0.
 #
-v86mov: 	movb 0x1(%esi),%bl		# Fetch Mod R/M byte
-		testb $0x10,%bl			# Read CR2 or CR3?
-		jnz v86mov.1			# Yes
-		movl %cr0,%eax			# Read CR0
-		testb $0x20,%bl			# Read CR4 instead?
-		jz v86mov.2			# No
-		movl %cr4,%eax			# Read CR4
-		jmp v86mov.2
-v86mov.1:	movl %cr2,%eax			# Read CR2
-		testb $0x08,%bl			# Read CR3 instead?
-		jz v86mov.2			# No
-		movl %cr3,%eax			# Read CR3
-v86mov.2:	andl $0x7,%ebx			# Compute offset in
-		shl $2,%ebx			#  frame of destination
-		neg %ebx			#  register
-		movl %eax,0x1c(%ebp,%ebx,1)	# Store CR to reg
+v86mov: 	movl %cr0,%eax			# CR0 to
+		movl %eax,0x1c(%ebp)		#  saved EAX
 		incl %esi			# Adjust IP
 #
 # Return from emulating a 0x0f prefixed instruction
@@ -618,27 +606,41 @@
 # reads count of words from saved %cx
 # returns success by setting %ah to 0
 #
-int15_87:	pushl %esi			# Save 
-		pushl %edi			#  registers
-		movzwl 0x4(%ebp),%eax		# Load user's SI
-		movl 0x3C(%ebp),%edi		# Load ES
-		leal (%eax,%edi,4),%edi		# EDI = (ES << 4) + SI
-		movl 0x11(%edi),%eax		# Read base of
-		movb 0x17(%edi),%al		#  GDT entry
-		ror $8,%eax			#  for source
-		xchgl %eax,%esi			#  into %esi
-		movl 0x19(%edi),%eax		# Read base of
-		movb 0x1f(%edi),%al		#  GDT entry for
-		ror $8,%eax			#  destination
-		xchgl %eax,%edi			#  into %edi
+int15_87:	pushl %eax			# Save 
+		pushl %ebx			#  some information 
+		pushl %esi			#  onto the stack.
+		pushl %edi
+		xorl %eax,%eax			# clean EAX 
+		xorl %ebx,%ebx			# clean EBX 
+		movl 0x4(%ebp),%esi		# Get user's ESI
+		movl 0x3C(%ebp),%ebx		# store ES
+		movw %si,%ax			# store SI
+		shll $0x4,%ebx			# Make it a seg.
+		addl %eax,%ebx			# ebx=(es<<4)+si
+		movb 0x14(%ebx),%al		# Grab the
+		movb 0x17(%ebx),%ah		#  necessary
+		shll $0x10,%eax			#  information
+		movw 0x12(%ebx),%ax		#  from
+		movl %eax,%esi			#  the
+		movb 0x1c(%ebx),%al		#  GDT in order to
+		movb 0x1f(%ebx),%ah		#  have %esi offset
+		shll $0x10,%eax			#  of source and %edi
+		movw 0x1a(%ebx),%ax		#  of destination.
+		movl %eax,%edi
 		pushl %ds			# Make:
 		popl %es			# es = ds
-		movzwl 0x18(%ebp),%ecx		# Get user's CX
-		shll $0x1,%ecx			# Convert count from words
+		pushl %ecx			# stash ECX
+		xorl %ecx,%ecx			# highw of ECX is clear
+		movw 0x18(%ebp),%cx		# Get user's ECX
+		shll $0x1,%ecx			# Convert from num words to num
+						#  bytes
 		rep				# repeat...
 		movsb				#  perform copy.
-		popl %edi			# Restore
-		popl %esi			#  registers
+		popl %ecx			# Restore
+		popl %edi
+		popl %esi			#  previous
+		popl %ebx			#  register
+		popl %eax			#  values.
 		movb $0x0,0x1d(%ebp)		# set ah = 0 to indicate
 						#  success
 		andb $0xfe,%dl			# clear CF
@@ -657,16 +659,23 @@
 		cmpb $0x19,%al			# is it int 19?
 		je reboot			#  yes, reboot the machine
 		cmpb $0x15,%al			# is it int 15?
-		jne v86intn.1			#  no, skip parse
-		cmpb $0x87,0x1c(%ebp)		# is it the memcpy subfunction?
-		je int15_87			#  yes
-		cmpw $0x4f53,0x1c(%ebp)		# is it the delete key callout?
-		jne v86intn.1			#  no, handle the int normally
+		jne v86intn.3			#  no, skip parse
+		pushl %eax                      # stash EAX
+		movl 0x1c(%ebp),%eax		# user's saved EAX
+		cmpb $0x87,%ah			# is it the memcpy subfunction?
+		jne v86intn.1			#  no, keep checking
+		popl %eax			# get the stack straight
+		jmp int15_87			# it's our cue
+v86intn.1:	cmpw $0x4f53,%ax		# is it the delete key callout?
+		jne v86intn.2			#  no, handle the int normally
 		movb BDA_KEYFLAGS,%al		# get the shift key state
 		andb $0xc,%al			# mask off just Ctrl and Alt
 		cmpb $0xc,%al			# are both Ctrl and Alt down?
-		je reboot			# yes, reboot the machine
-v86intn.1:	subl %edi,%esi			# From
+		jne v86intn.2			#  no, handle the int normally
+		popl %eax			# restore EAX
+		jmp reboot			# reboot the machine
+v86intn.2:	popl %eax			# restore EAX
+v86intn.3:	subl %edi,%esi			# From
 		shrl $0x4,%edi			#  linear
 		movw %dx,-0x2(%ebx)		# Save flags
 		movw %di,-0x4(%ebx)		# Save CS
@@ -898,7 +907,8 @@
 dump.3: 	lodsl				# Set offset
 		xchgl %eax,%edx 		# Save
 		lodsl				# Get segment
-		leal (%edx,%eax,4),%eax		#  * 0x10 + offset
+		shll $0x4,%eax			#  * 0x10
+		addl %edx,%eax			#  + offset
 		xchgl %eax,%esi 		# Set pointer
 dump.4: 	movb $2,%dl			# Num lines
 dump.4a:	movb $0x10,%cl			# Bytes to dump