Source code of Windows XP (NT5)
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PAGE ,132
TITLE DXBUG.ASM -- Dos Extender Debug Services
; Copyright (c) Microsoft Corporation 1989-1991. All Rights Reserved.
;****************************************************************
;* *
;* DXBUG.ASM - Dos Extender Debug Services *
;* *
;****************************************************************
;* *
;* Module Description: *
;* *
;* This module contains protect mode debug services for the *
;* DOS extender. *
;* *
;****************************************************************
;* Revision History: *
;* *
;* 11/17/89 Jimmat Added TraceBug stuff for debugging on *
;* 286 machines. *
;* 03/09/89 JimMat Initial version. *
;* *
;****************************************************************
.286p
.287
ifndef DEBUG
DEBUG = 0
endif
; -------------------------------------------------------
; INCLUDE FILE DEFINITIONS
; -------------------------------------------------------
include segdefs.inc
include gendefs.inc
include pmdefs.inc
if DEBUG ;********** ENTIRE FILE IS DEBUG CODE ***********
; -------------------------------------------------------
; DATA SEGMENT DEFINITIONS
; -------------------------------------------------------
DXDATA segment
extrn fDebug:BYTE
extrn fTraceBug:WORD
;******************************************************************************
;
; DXOutputDebugStr
;
; Basically stolen from Windows/386 code by Ralph Lipe -- hacked up for
; 286 instead of 386. Here in RalphL's own words is the description:
;
; DESCRIPTION:
; The following code is not pretty but it does what it needs to. It will
; only be included in DEBUG versions of Win386. It accepts an ASCIIZ
; string which it will output to the COM1 serial port. If the string
; contains #(Register) (for example #AX) then the value of that register
; will be output. It will not work for segment registers.
;
; If the string contains ?(Register)[:(Register)] (for example ?AX or
; ?AX:BX) then the value of the register(s) is passed to the debugger
; to display the label nearest to the given address. (It, also, will
; not work with segment registers. If ?AX is given, then the segment is
; assumed to be the DX code segment.
;
; ENTRY:
; DS:SI -> ASCIIZ string
;
; EXIT:
; All registers and flags trashed
;
; ASSUMES:
; This procedure was called by the Trace_Out macro. It assumes that
; the stack is a pushad followed by a FAR call to this procedure.
;
;------------------------------------------------------------------------------
Reg_Offset_Table LABEL WORD ; Order of PUSHA
dw "DI"
dw "SI"
dw "BP"
dw "SP"
dw "BX"
dw "DX"
dw "CX"
dw "AX"
DXDATA ends
DXCODE segment
assume cs:DXCODE
public DXOutDebugStr
DXOutDebugStr proc far
push bp
mov bp, sp ; Assumes BP+6 = Pusha
pushf
push es
push SEL_DXDATA ; Address our own data seg
pop es
assume ds:NOTHING,es:DGROUP
cld
cli
OSC1_Loop:
lodsb ; Get the next character
test al, al ; Q: End of string?
jz short OSC1_Done ; Y: Return
cmp al, "#" ; N: Q: Special register out?
je SHORT OSC1_Hex ; Y: Find out which one
cmp al, "?" ; Q: special lable out?
je short OSC1_Label ; Y: find out which one
cmp al, "@" ; Q: special string out?
je short OSC1_Str
OSC1_out:
xor ah, ah ; N: Send char to COM
call Out_Debug_Chr
jmp OSC1_Loop ; Loop until done
OSC1_Hex:
call Get_Register
jnc short OSC1_not_special
cmp bl, 2 ; Q: Word output?
jb SHORT OSC1_Out_Byte ; N: display byte
OSC1_Out_Word:
call Out_Hex_Word ; Display AX in hex
jmp OSC1_Loop ; Output next char
OSC1_Out_Byte:
xchg al, ah ; swap bytes to print just
call Out_Hex_Byte ; the low one!
jmp OSC1_Loop ; Output next char
OSC1_Label:
call Get_Register
jc short show_label
OSC1_not_special:
lodsb ; Get special char again
jmp OSC1_out ; display it, and continue
show_label:
mov cx, ax ; save first value
cmp byte ptr [si], ':' ;Q: selector separator?
jne short flat_offset ; N:
lodsb ; Y: eat the ':'
call Get_Register ; and attempt to get the selector
jc short sel_offset
flat_offset:
mov ax, cs ; default selector value
sel_offset:
call Show_Near_Label
jmp OSC1_Loop
OSC1_Str:
call Get_Register
jnc short OSC1_not_special
mov cx,ax
cmp byte ptr [si],':'
jne short no_selector
lodsb
push cx
call Get_Register
pop cx
xchg ax,cx
jc short got_sel_off
mov cx,ax
no_selector:
mov ax,ds ; default selector for strings
got_sel_off:
call Show_String
jmp OSC1_Loop
OSC1_Done: ; The end
pop es
npopf
pop bp
ret 10h
DXOutDebugStr endp
;******************************************************************************
;
; Get_Register
;
; DESCRIPTION:
;
; ENTRY:
;
; EXIT: Carry set if register value found
; AX = register value
; BL = value size (1, 2, 4)
;
; USES:
;
;==============================================================================
Get_Register proc near
push si ; Save string pointer
xor ax, ax ; Zero AX
mov bl, 2 ; BL = 2 (assume word output)
call Load_Up_Char ; Get 1st char
mov ah, al ; Move 1st char to AH
call Load_Up_Char ; Get second char
cmp al, 'L' ; Q: "L" (ie AL, BL, etc)?
jne short OSC1_WORD ; N: word reg
mov al, 'X' ; Y: change to X for pos match
mov bl, 1 ; BL = 1 -- byte output
OSC1_WORD:
xor di, di ; DI = 0
mov cx, 8 ; Size of a pusha
OSC1_Special_Loop:
push di
shl di,1
cmp ax, Reg_Offset_Table[di] ; Q: Is this the register?
pop di
je SHORT OSC1_Out_Reg ; Y: Output it
inc di ; N: Try the next one
loop OSC1_Special_Loop ; until CX = 0
OSC1_Ignore_Special: ; OOPS! backup and ignore special
pop si ; Restore original string ptr
dec si ; back up to special char
clc
jmp short gr_exit
OSC1_Out_Reg:
push di
shl di,1
mov ax, SS:[bp.6][di] ; AX = Value to output
pop di
add sp, 2 ; Trash pushed SI
cmp bl, 2 ;Q: byte or word value?
je short value_fnd ; jump if word value
xor ah, ah ; clear ah, if byte value
value_fnd:
stc
gr_exit:
ret
Get_Register endp
;******************************************************************************
;
; Load_Up_Char
;
; Moves the character at DS:SI into AL and converts it to an upper case
; character. SI is incremented.
;
;------------------------------------------------------------------------------
Load_Up_Char proc near
lodsb
cmp al, "Z"
jb SHORT LUC_Done
sub al, "a" - "A"
LUC_Done:
ret
Load_Up_Char endp
;******************************************************************************
;
; Out_Hex_Word
;
; Outputs the value in AX to the COM port in hexadecimal.
;
;------------------------------------------------------------------------------
Out_Hex_Word proc near
rol ax, 4
call Out_Hex_Char
rol ax, 4
call Out_Hex_Char
Out_Hex_Byte:
rol ax, 4
call Out_Hex_Char
rol ax, 4
call Out_Hex_Char
ret
Out_Hex_Word endp
;******************************************************************************
;
; Out_Hex_Char
;
; Outputs the low nibble in AL to the COM port.
;
;------------------------------------------------------------------------------
DXDATA segment
Hex_Char_Tab LABEL BYTE
db "0123456789ABCDEF"
DXDATA ends
Out_Hex_Char proc near
push ax
push bx
mov bx, ax
and bx, 1111b
mov al, Hex_Char_Tab[bx]
call Out_Debug_Chr
pop bx
pop ax
ret
Out_Hex_Char endp
;******************************************************************************
;
; Out_Debug_Chr
;
; DESCRIPTION:
;
; ENTRY:
; AL contains character to output
;
; EXIT:
;
; USES:
; Nothing
;
;==============================================================================
Out_Debug_Chr proc near
assume ds:nothing,es:DGROUP
if 0
push ax
mov ax,cs
cmp ax,SEL_DXCODE0 ; Are we in real mode?
pop ax
jne out_com
cmp fDebug,0 ; debugger installed?
je out_com ; N: go output it ourselves
push ax
push dx
mov dl, al
mov ax, DS_Out_Char
int Debug_Serv_Int
pop dx
pop ax
endif
ret
Out_Debug_Chr endp
;******************************************************************************
;
; Show_Near_Label
;
; DESCRIPTION: call the debugger to display a label less than or equal
; to the given address
;
; ENTRY: AX is selector, CX is offset of address to try to find
; a symbol for
; ES selector to DOSX data segment
; EXIT:
;
; USES:
;
;==============================================================================
Show_Near_Label proc near
if 0
push ax
mov ax,cs
cmp ax,SEL_DXCODE0 ; Are we in real mode?
pop ax
jne Show_Near_Label_ret
cmp es:idCpuType,3 ;use 32 bit regs?
jae debug_386
push ax ;on a 286, use 16 bit regs
push bx
push cx
mov bx,cx
mov cx,ax
mov ax,DS_Out_Symbol
int Debug_Serv_Int
pop cx
pop bx
pop ax
endif
ret
if 0
debug_386:
.386p
push eax
push ebx
push ecx
mov bx, cx
movzx ecx, ax ;WDEB386 wants a 32 bit offset
mov ax, DS_Out_Symbol
int Debug_Serv_Int
pop ecx
pop ebx
pop eax
ret
.286p
Show_Near_Label_ret:
endif
Show_Near_Label endp
;******************************************************************************
;
; Show_String
;
; DESCRIPTION: Display an asciiz string
;
; ENTRY: AX is selector, CX is offset of address to find string
;
; EXIT:
;
; USES:
;
;==============================================================================
Show_String proc near
if 0
push ax
push ds
push si
mov ds,ax
mov si,cx
xor ax,ax
@@:
lodsb
or al,al
jz @f
call Out_Debug_Chr
jmp short @b
@@:
pop si
pop ds
pop ax
endif
ret
Show_String endp
DXCODE ends
endif ; DEBUG
end