PERFORCE change 119083 for review

[Alexey Tarasov]

http://perforce.freebsd.org/chv.cgi?CH=119083

Change 119083 by taleks at taleks_th on 2007/05/01 13:39:58

	made first version of compilable assembler code. Updated isr_install definition, int_num now is 16bit to simplify popping it from stack.

Affected files ...

.. //depot/projects/soc2007/taleks-pxe_http/btx_mod/btx/btx.S#3 edit
.. //depot/projects/soc2007/taleks-pxe_http/btx_mod/lib/btxv86.h#3 edit

Differences ...

==== //depot/projects/soc2007/taleks-pxe_http/btx_mod/btx/btx.S#3 (text+ko) ====

@@ -871,7 +871,8 @@
 		jmp exit			# Exit
 /*
  *	Here we need to modify IDT in such way, that at interrupt handle
- *  will be run isr_trump, which role is to run provided function in user space.
+ *  will be run user_isr_call, which role is to run provided function
+ *  in user space.
  */
 intx30.2:	xorl %eax,%eax			# clear eax
 
@@ -879,44 +880,51 @@
  * updating call gate
  */
  		mov gdtdesc,%edi		# calculating descriptors entry
- 		add $SEL_CALLGATE, %edi		# pointing callgate selector
+ 		add $SEL_CALLGATE,%edi		# pointing callgate selector
 
 		popl %eax			# got 32bit offset to handler
 
-		mov %ax, (%di)			# +0: store offset
-		shr $0x10, %eax			# getting high word
-		mov %ax, 0x6(%di)		# +6: handler offset 16..31
+		movw %ax,(%edi)			# +0: store offset 00..15
+		shr $0x10,%eax			# getting high word
+		add $0x06,%edi			# +6:
+		mov %ax,(%edi)			#   handler offset 16..31
 /*
  * installing handler
  */
- 		xor %ax,%ax			# clear eax
- 		pop %ah				# getting interrupt number
- 		mul $0x08,%ax			#
+ 		xor %ax,%ax			# clear ax
+ 		pop %ax				# getting interrupt number
+ 		mov $0x08, %bl			#
+ 		mulb %bl			#
 
-		mov $MEM_IDT, %di		# point to IDT.
+		mov $MEM_IDT,%di		# point to IDT.
 		add %ax,%di			# calculate entry
 
 		mov $SEL_SCODE,%dh		# supervisor code selector
-		mov user_isr_call, %ax		# tramp address
+		mov user_isr_call,%ax		# tramp address
 
-		mov $0x8e, %dl			# i386+ interrupt gate, DPL=0
+		mov $0x8e,%dl			# i386+ interrupt gate, DPL=0
 
-		mov %ax,(%di)			# 0: handler offset 0..15
-		mov %dh,0x2(%di)		# +2: dest selector
-						# +4: 000:word_count
-		mov %dl,0x5(%di)		# +5: P:DPL:type
+		mov %ax,(%edi)			# 0: handler offset 0..15
+		mov %dh,0x2(%edi)		# +2: dest selector
+						# +4: 000:word_count=0
+		mov %dl,0x5(%edi)		# +5: P:DPL:type
 						# +6: handler offset 16..31
 /*
- *  NOTE: do we need flush caches?
+ *  NOTE: it seems nothing else must be done
  */
 		iret				# return from syscall
 
 user_isr_call:
 /*
- * NOTE: do we need update CS,DS & etc before and restore after?
+ * NOTE: isr must use lret to return and restore SS, ESP, CS, EIP.
 */
-						# far call via callgate selector
-		lcall $SEL_S2U_CALL		# NOTE: find how it must be.
+		push %ds			# saving ds
+		mov $SEL_UDATA,%ax		#
+		mov %ax,%ds			# setting it to userspace data
+						# cs is updated from selector
+		lcall $SEL_CALLGATE,$0x00000000	# far call via callgate selector
+						# offset is ignored
+		pop %ds				# restore data segment
 		iret				# return from interrupt handler
 
 /*

==== //depot/projects/soc2007/taleks-pxe_http/btx_mod/lib/btxv86.h#3 (text+ko) ====

@@ -63,6 +63,6 @@
  *  Installs interrupt handler function for interrupt int_num.
  *  caddr_t - in userspace.
  */
-void __isr_install(caddr_t isr, uint8_t int_num);
+void __isr_install(caddr_t isr, uint16_t int_num);
 
 #endif /* !_BTXV86_H_ */