diff options
Diffstat (limited to 'Build/source/extra/jpeg/jmemdosa.asm')
-rw-r--r-- | Build/source/extra/jpeg/jmemdosa.asm | 379 |
1 files changed, 379 insertions, 0 deletions
diff --git a/Build/source/extra/jpeg/jmemdosa.asm b/Build/source/extra/jpeg/jmemdosa.asm new file mode 100644 index 00000000000..ecd43729fe5 --- /dev/null +++ b/Build/source/extra/jpeg/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 |