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diff --git a/libjpegtwrp/jmemdosa.asm b/libjpegtwrp/jmemdosa.asm
new file mode 100644
index 000000000..ecd43729f
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+++ b/libjpegtwrp/jmemdosa.asm
@@ -0,0 +1,379 @@
+;
+; jmemdosa.asm
+;
+; Copyright (C) 1992, Thomas G. Lane.
+; This file is part of the Independent JPEG Group's software.
+; For conditions of distribution and use, see the accompanying README file.
+;
+; This file contains low-level interface routines to support the MS-DOS
+; backing store manager (jmemdos.c).  Routines are provided to access disk
+; files through direct DOS calls, and to access XMS and EMS drivers.
+;
+; This file should assemble with Microsoft's MASM or any compatible
+; assembler (including Borland's Turbo Assembler).  If you haven't got
+; a compatible assembler, better fall back to jmemansi.c or jmemname.c.
+;
+; To minimize dependence on the C compiler's register usage conventions,
+; we save and restore all 8086 registers, even though most compilers only
+; require SI,DI,DS to be preserved.  Also, we use only 16-bit-wide return
+; values, which everybody returns in AX.
+;
+; Based on code contributed by Ge' Weijers.
+;
+
+JMEMDOSA_TXT	segment byte public 'CODE'
+
+		assume	cs:JMEMDOSA_TXT
+
+		public	_jdos_open
+		public	_jdos_close
+		public	_jdos_seek
+		public	_jdos_read
+		public	_jdos_write
+		public	_jxms_getdriver
+		public	_jxms_calldriver
+		public	_jems_available
+		public	_jems_calldriver
+
+;
+; short far jdos_open (short far * handle, char far * filename)
+;
+; Create and open a temporary file
+;
+_jdos_open	proc	far
+		push	bp			; linkage
+		mov 	bp,sp
+		push	si			; save all registers for safety
+		push	di
+		push	bx
+		push	cx
+		push	dx
+		push	es
+		push	ds
+		mov	cx,0			; normal file attributes
+		lds	dx,dword ptr [bp+10]	; get filename pointer
+		mov	ah,3ch			; create file
+		int	21h
+		jc	open_err		; if failed, return error code
+		lds	bx,dword ptr [bp+6]	; get handle pointer
+		mov	word ptr [bx],ax	; save the handle
+		xor	ax,ax			; return zero for OK
+open_err:	pop	ds			; restore registers and exit
+		pop	es
+		pop	dx
+		pop	cx
+		pop	bx
+		pop	di
+		pop	si
+		pop 	bp
+		ret
+_jdos_open	endp
+
+
+;
+; short far jdos_close (short handle)
+;
+; Close the file handle
+;
+_jdos_close	proc	far
+		push	bp			; linkage
+		mov 	bp,sp
+		push	si			; save all registers for safety
+		push	di
+		push	bx
+		push	cx
+		push	dx
+		push	es
+		push	ds
+		mov	bx,word ptr [bp+6]	; file handle
+		mov	ah,3eh			; close file
+		int	21h
+		jc	close_err		; if failed, return error code
+		xor	ax,ax			; return zero for OK
+close_err:	pop	ds			; restore registers and exit
+		pop	es
+		pop	dx
+		pop	cx
+		pop	bx
+		pop	di
+		pop	si
+		pop 	bp
+		ret
+_jdos_close	endp
+
+
+;
+; short far jdos_seek (short handle, long offset)
+;
+; Set file position
+;
+_jdos_seek	proc	far
+		push	bp			; linkage
+		mov 	bp,sp
+		push	si			; save all registers for safety
+		push	di
+		push	bx
+		push	cx
+		push	dx
+		push	es
+		push	ds
+		mov	bx,word ptr [bp+6]	; file handle
+		mov	dx,word ptr [bp+8]	; LS offset
+		mov	cx,word ptr [bp+10]	; MS offset
+		mov	ax,4200h		; absolute seek
+		int	21h
+		jc	seek_err		; if failed, return error code
+		xor	ax,ax			; return zero for OK
+seek_err:	pop	ds			; restore registers and exit
+		pop	es
+		pop	dx
+		pop	cx
+		pop	bx
+		pop	di
+		pop	si
+		pop 	bp
+		ret
+_jdos_seek	endp
+
+
+;
+; short far jdos_read (short handle, void far * buffer, unsigned short count)
+;
+; Read from file
+;
+_jdos_read	proc	far
+		push	bp			; linkage
+		mov 	bp,sp
+		push	si			; save all registers for safety
+		push	di
+		push	bx
+		push	cx
+		push	dx
+		push	es
+		push	ds
+		mov	bx,word ptr [bp+6]	; file handle
+		lds	dx,dword ptr [bp+8]	; buffer address
+		mov	cx,word ptr [bp+12]	; number of bytes
+		mov	ah,3fh			; read file
+		int	21h
+		jc	read_err		; if failed, return error code
+		cmp	ax,word ptr [bp+12]	; make sure all bytes were read
+		je	read_ok
+		mov	ax,1			; else return 1 for not OK
+		jmp	short read_err
+read_ok:	xor	ax,ax			; return zero for OK
+read_err:	pop	ds			; restore registers and exit
+		pop	es
+		pop	dx
+		pop	cx
+		pop	bx
+		pop	di
+		pop	si
+		pop 	bp
+		ret
+_jdos_read	endp
+
+
+;
+; short far jdos_write (short handle, void far * buffer, unsigned short count)
+;
+; Write to file
+;
+_jdos_write	proc	far
+		push	bp			; linkage
+		mov 	bp,sp
+		push	si			; save all registers for safety
+		push	di
+		push	bx
+		push	cx
+		push	dx
+		push	es
+		push	ds
+		mov	bx,word ptr [bp+6]	; file handle
+		lds	dx,dword ptr [bp+8]	; buffer address
+		mov	cx,word ptr [bp+12]	; number of bytes
+		mov	ah,40h			; write file
+		int	21h
+		jc	write_err		; if failed, return error code
+		cmp	ax,word ptr [bp+12]	; make sure all bytes written
+		je	write_ok
+		mov	ax,1			; else return 1 for not OK
+		jmp	short write_err
+write_ok:	xor	ax,ax			; return zero for OK
+write_err:	pop	ds			; restore registers and exit
+		pop	es
+		pop	dx
+		pop	cx
+		pop	bx
+		pop	di
+		pop	si
+		pop 	bp
+		ret
+_jdos_write	endp
+
+
+;
+; void far jxms_getdriver (XMSDRIVER far *)
+;
+; Get the address of the XMS driver, or NULL if not available
+;
+_jxms_getdriver	proc	far
+		push	bp			; linkage
+		mov 	bp,sp
+		push	si			; save all registers for safety
+		push	di
+		push	bx
+		push	cx
+		push	dx
+		push	es
+		push	ds
+		mov 	ax,4300h		; call multiplex interrupt with
+		int	2fh			; a magic cookie, hex 4300
+		cmp 	al,80h			; AL should contain hex 80
+		je	xmsavail
+		xor 	dx,dx			; no XMS driver available
+		xor 	ax,ax			; return a nil pointer
+		jmp	short xmsavail_done
+xmsavail:	mov 	ax,4310h		; fetch driver address with
+		int	2fh			; another magic cookie
+		mov 	dx,es			; copy address to dx:ax
+		mov 	ax,bx
+xmsavail_done:	les 	bx,dword ptr [bp+6]	; get pointer to return value
+		mov	word ptr es:[bx],ax
+		mov	word ptr es:[bx+2],dx
+		pop	ds			; restore registers and exit
+		pop	es
+		pop	dx
+		pop	cx
+		pop	bx
+		pop	di
+		pop	si
+		pop	bp
+		ret
+_jxms_getdriver	endp
+
+
+;
+; void far jxms_calldriver (XMSDRIVER, XMScontext far *)
+;
+; The XMScontext structure contains values for the AX,DX,BX,SI,DS registers.
+; These are loaded, the XMS call is performed, and the new values of the
+; AX,DX,BX registers are written back to the context structure.
+;
+_jxms_calldriver 	proc	far
+		push	bp			; linkage
+		mov 	bp,sp
+		push	si			; save all registers for safety
+		push	di
+		push	bx
+		push	cx
+		push	dx
+		push	es
+		push	ds
+		les 	bx,dword ptr [bp+10]	; get XMScontext pointer
+		mov 	ax,word ptr es:[bx]	; load registers
+		mov 	dx,word ptr es:[bx+2]
+		mov 	si,word ptr es:[bx+6]
+		mov 	ds,word ptr es:[bx+8]
+		mov 	bx,word ptr es:[bx+4]
+		call	dword ptr [bp+6]	; call the driver
+		mov	cx,bx			; save returned BX for a sec
+		les 	bx,dword ptr [bp+10]	; get XMScontext pointer
+		mov 	word ptr es:[bx],ax	; put back ax,dx,bx
+		mov 	word ptr es:[bx+2],dx
+		mov 	word ptr es:[bx+4],cx
+		pop	ds			; restore registers and exit
+		pop	es
+		pop	dx
+		pop	cx
+		pop	bx
+		pop	di
+		pop	si
+		pop 	bp
+		ret
+_jxms_calldriver 	endp
+
+
+;
+; short far jems_available (void)
+;
+; Have we got an EMS driver? (this comes straight from the EMS 4.0 specs)
+;
+_jems_available	proc	far
+		push	si			; save all registers for safety
+		push	di
+		push	bx
+		push	cx
+		push	dx
+		push	es
+		push	ds
+		mov	ax,3567h		; get interrupt vector 67h
+		int	21h
+		push	cs
+		pop	ds
+		mov	di,000ah		; check offs 10 in returned seg
+		lea	si,ASCII_device_name	; against literal string
+		mov	cx,8
+		cld
+		repe cmpsb
+		jne	no_ems
+		mov	ax,1			; match, it's there
+		jmp	short avail_done
+no_ems:		xor	ax,ax			; it's not there
+avail_done:	pop	ds			; restore registers and exit
+		pop	es
+		pop	dx
+		pop	cx
+		pop	bx
+		pop	di
+		pop	si
+		ret
+
+ASCII_device_name	db	"EMMXXXX0"
+
+_jems_available	endp
+
+
+;
+; void far jems_calldriver (EMScontext far *)
+;
+; The EMScontext structure contains values for the AX,DX,BX,SI,DS registers.
+; These are loaded, the EMS trap is performed, and the new values of the
+; AX,DX,BX registers are written back to the context structure.
+;
+_jems_calldriver	proc far
+		push	bp			; linkage
+		mov 	bp,sp
+		push	si			; save all registers for safety
+		push	di
+		push	bx
+		push	cx
+		push	dx
+		push	es
+		push	ds
+		les 	bx,dword ptr [bp+6]	; get EMScontext pointer
+		mov 	ax,word ptr es:[bx]	; load registers
+		mov 	dx,word ptr es:[bx+2]
+		mov 	si,word ptr es:[bx+6]
+		mov 	ds,word ptr es:[bx+8]
+		mov 	bx,word ptr es:[bx+4]
+		int	67h			; call the EMS driver
+		mov	cx,bx			; save returned BX for a sec
+		les 	bx,dword ptr [bp+6]	; get EMScontext pointer
+		mov 	word ptr es:[bx],ax	; put back ax,dx,bx
+		mov 	word ptr es:[bx+2],dx
+		mov 	word ptr es:[bx+4],cx
+		pop	ds			; restore registers and exit
+		pop	es
+		pop	dx
+		pop	cx
+		pop	bx
+		pop	di
+		pop	si
+		pop 	bp
+		ret
+_jems_calldriver	endp
+
+JMEMDOSA_TXT	ends
+
+		end