DOS-debug

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;--- debug printf - all registers preserved, including flags
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;--- DEBUGR variant, compatible with 32-bit stack
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handle_char proc
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	cmp al,10
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	jnz @F
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	mov al,13
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	call @F
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	mov al,10
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@@:
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	push bx
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	xor bx,bx
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	mov ah,0Eh
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	call cs:[int10vec]
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	pop bx
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	ret
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handle_char endp
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;--- ltob(long n, char * s, int base);
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;--- convert long to string
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;--- eax=number
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;--- ss:ebx=buffer
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;--- cx=base
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ltob PROC 
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	push edi
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	movzx edi, cx
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	mov ch,0
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	cmp di,-10
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	jne @F
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	mov di,10
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	and eax,eax
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	jns @F
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	neg eax
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	mov ch,'-'
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@@:
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	add ebx,10
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	mov BYTE PTR ss:[ebx],0
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	dec ebx
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@@nextdigit:
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	xor edx, edx
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	div edi
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	add dl,'0'
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	cmp dl,'9'
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	jbe @F
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	add dl,7+20h
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@@:
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	mov ss:[ebx],dl
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	dec ebx
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	and eax, eax
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	jne @@nextdigit
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	cmp ch,0
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	je @F
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	mov ss:[ebx],ch
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	dec ebx
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@@:
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	inc ebx
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	mov eax,ebx
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	pop edi
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	ret
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ltob ENDP
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;--- ds unused; ss unknown, may be 16- or 32-bit.
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;--- tiny model ( strings may be addressed with CS ) assumed.
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dprintf PROC
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d_esp     equ <dword ptr [ebp+32+2]>
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d_ret     equ <word ptr [ebp+32+2+4]>
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d_fmt     equ <word ptr [ebp+32+2+4+2]>
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d_args    equ <[ebp+32+2+4+2+2]>
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d_size    equ <word ptr [ebp-2]>
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d_flag    equ <byte ptr [ebp-3]>
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d_longarg equ <byte ptr [ebp-4]>
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d_fill    equ <byte ptr [ebp-5]>
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d_szTmp   equ <[ebp-18]>
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	push esp
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	pushf
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	pushad
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	mov ebp, esp
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	sub esp, 18
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	mov ax, ss
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	lar eax, eax
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	bt eax, 22
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	jc @F
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	movzx ebp, bp
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@@:
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	lea edi, d_args
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@@L335:
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	mov si, d_fmt
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nextchar:
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	lodsb cs:[si]
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	or al,al
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	je done
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	cmp al,'%'
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	je formatitem
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	call handle_char
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	jmp nextchar
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done:
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	sub edi, 2
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	mov ax, d_ret
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	mov ss:[edi], ax
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	mov d_esp, edi
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	add esp, 18
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	popad
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	popf
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	pop esp
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	ret
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formatitem:
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	push @@L335
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	xor dx,dx
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	mov d_longarg,dl
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	mov bl,1
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	mov cl,' '
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	cmp BYTE PTR cs:[si],'-'
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	jne @F
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	dec bx
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	inc si
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@@:
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	mov d_flag, bl
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	cmp BYTE PTR cs:[si],'0'
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	jne @F
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	mov cl,'0'
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	inc si
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@@:
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	mov d_fill,cl
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	mov bx,dx
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@@:
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	lodsb cs:[si]
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	cmp al, '0'
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	jb numdone
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	cmp al, '9'
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	ja numdone
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	sub al,'0'
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	cbw
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	imul cx,bx,10		;cx = bx * 10
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	add ax,cx
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	mov bx,ax
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	jmp @B
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numdone:
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	dec si
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	mov d_size, bx
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	cmp BYTE PTR cs:[si],'l'
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	jne @F
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	mov d_longarg,1
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	inc si
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@@:
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	lodsb cs:[si]
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	mov d_fmt,si
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	cmp al,'x'
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	je handle_x
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	cmp al,'X'
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	je handle_x
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	cmp al,'c'
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	je handle_c
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	cmp al,'d'
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	je handle_d
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	cmp al,'i'
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	je handle_i
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	cmp al,'s'
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	je handle_s
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	cmp al,'u'
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	je handle_u
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	cmp al,0
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	jnz @@L359
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	pop ax
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	jmp done
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handle_c:
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	mov ax,ss:[edi]
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	add edi,2
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@@L359:
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	call handle_char
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	retn
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handle_x:
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	mov cx,16
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	jmp @@lprt262
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handle_d:
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handle_i:
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	mov cx,-10
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	jmp @@lprt262
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handle_u:
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	mov cx,10
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@@lprt262:
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	mov ax,ss:[edi]
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	add edi,2
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	sub dx,dx
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	cmp cx,0		;signed or unsigned?
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	jge @F
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	cwd
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@@:
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	cmp d_longarg,0
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	je @F
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	mov dx,ss:[edi]
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	add edi,2
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@@:
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	lea ebx, d_szTmp
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	push dx
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	push ax
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	pop eax
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;	invoke ltob, eax, bx, cx
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	call ltob
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	mov esi,eax
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	.while byte ptr ss:[esi]
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		lodsb ss:[esi]
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		call handle_char
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	.endw
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	retn
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handle_s:
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	mov si,ss:[edi]
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	add edi,2
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output_string:	;display string at ds:si
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	mov ax,si
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	mov bx,d_size
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	.while byte ptr cs:[si]
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		inc si
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	.endw
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	sub si,ax
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	xchg ax,si
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	sub bx,ax
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	.if d_flag == 1
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		.while sword ptr bx > 0
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			mov al, d_fill
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			call handle_char
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			dec bx
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		.endw
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	.endif
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	.while byte ptr cs:[si]
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		lodsb cs:[si]
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		call handle_char
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	.endw
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	.while sword ptr bx > 0
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		mov al, d_fill
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		call handle_char
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		dec bx
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	.endw
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	retn
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dprintf ENDP
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d_esp     equ <>
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d_ret     equ <>
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d_fmt     equ <>
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d_args    equ <>
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d_size    equ <>
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d_flag    equ <>
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d_longarg equ <>
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d_fill    equ <>
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d_szTmp   equ <>
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