Power-Programmierung/CD2.mdf/c/library/dos/memory/xm/xmfile.asm

Assembly Source File | 1990-10-08 | 4.2 KB | 256 lines

        .386
O_APPEND    equ    8
O_CREAT        equ    100h
O_TRUNC        equ    200h
O_EXCL        equ    400h


        include xmhd.inc
        include xmmac.mac
        include    termio.inc
        include    stat.inc
        include    exp.inc
        include xmmsg.def

_DATA        segment    para public USE16 'DATA'


        extrn    EData:byte, EBSS:byte
        extrn    ECode:byte
        extrn    Param:dword
        extrn    DosWorkI: byte, DosWorkO: byte
        extrn    PSPWork: dword
        public    fhdr

;FileName    db    MAXFILENAME+2 dup (0)

fhdr        filehdr    <>
comment %
ahdr        aouthdr    <>
shdr        scnhdr    <>
%

NotSupported    db    'This format is not supported',13,10,0
Default_ext    db    '.exp',0

        public    Handle
Handle        dw    ?

_DATA        ends
;
_TEXT        segment    para public USE16 'CODE'
        assume    cs:_TEXT, ds:_DATA
;
        public    ReadFOHdr, ReadSHdr
        public    OpenExe, AddExtention
        extrn    OSExit: near
IF FMR70
        extrn    a20_off: near, a20_on:near
ENDIF

ReadFOHdr    proc    near        ; read file header
IF FMR70
        call    a20_off
ENDIF
        mov    bx, Handle
        mov    ah, 3fh
        mov    dx, offset fhdr
        mov    cx, (size fhdr)
        int    21h
        jc    Error
        cmp    ax, cx
        jc    Error

        mov    ax, fhdr.f_magic
        cmp    ax, EXPMAGIC
        je    read_fh_ok
        cmp    ax, AoutMagic
        je    read_fh_ok
        jne    Error
read_fh_ok:
        ret
ReadFOHdr    endp

ReadSHdr    proc    near        ; read section headers
        mov    bx, offset fhdr
        cmp    [bx].f_magic, EXPMAGIC
        jne    read_aout
read_exp:
        mov    dx, [bx].f_nhdr
        shl    dx, 4
        mov    cx, 0
        mov    bx, Handle
        mov    ah, 42h       ; skip header parts
        mov    al, 0        ; seek from top of file
        int    21h        ;
        jc    Error
;read code
        movzx    ebx, Handle
        mov    Param[0], ebx
        mov    eax, ECode.Base
        mov    Param[4],eax        ; code area to load in
        push    eax
        movzx    eax, fhdr.f_npage
        shl    eax, 9
        movzx    ebx, fhdr.f_nbyte
        add    eax, ebx
        movzx    ebx, fhdr.f_nhdr
        shl    ebx, 4
        sub    eax, ebx
        mov    Param[8], eax        ; bytes to readin
        mov    si, psp_mem_min
        mov    dword ptr PSPwork[si], eax
        mov    ECode.Hi, eax
;
        push    eax
        neg    eax
        add    eax, EData.Hi
;        sub    eax, EData.Base
        mov    si, psp_mem_bss
        mov    dword ptr PSPwork[si], eax

        mov    eax, EData.Hi
;        sub    eax, EData.Base
        mov    si, psp_mem_max
;
; allocate communication buffer
;
        sub    eax, 1000h
        mov    dword ptr PSPwork[si], eax
        mov    EBSS.Hi, eax
        pop    eax
;
        pop    ebx
        add    eax, ebx        ; start + size
;        mov    ECode.Hi, eax
        inc    eax
        mov    EBSS.Lo, eax
        xor    eax,eax
;        mov    ECode.Lo, eax
;        mov    EData.Lo, eax

; setup transfer addres in es:edi
;
        push    es
        mov    ax, ds
        mov    es, ax
        movzx    eax, ax
        shl    eax, 4
        mov    edi, ECode.Base     ;48bit pointer
        sub    edi, eax
        cld
;
; read file into inner buffer
.readloop:
IF FMR70
        call    a20_off
ENDIF
        mov    cx, PageSize
        lea    dx, DosWorkI        ;PageBuffer
        mov    ah, 3fh
        mov    bx, Handle
        int    21h
        jc    Error
;
        mov    cx, ax
        jcxz    .done
IF FMR70
        call    a20_on
ENDIF
        lea    esi, DosWorkI        ;PageBuffer
        prefix32
    rep    movsb
        jmp    .readloop
.done:
        pop    es
        ret
ReadSHdr    endp

AddExtention    proc    near
        push    di
        push    si
        push    cx
        push    ax
        mov    di, offset fileName
        mov    al, 0
        mov    cx, MAXFILENAME
        cld
    repne    scasb
        cmp    cx, 0
        je    .add_no
        dec    di
        mov    si, offset default_ext
        mov    cx, 5            ; '.xxx'+EOS
    rep    movsb
.add_no:
        pop    ax
        pop    cx
        pop    si
        pop    di
        ret
AddExtention    endp

OpenExe        proc    near
IF FMR70
        call    a20_off
ENDIF
        mov    al, byte ptr FileName
        cmp    al, 0
        je    .file_not_found
        mov    dx, offset FileName
        mov    ax, 3d00h    ;open for reading
        je    .file_not_found
        int    21h
        mov    Handle, ax
        jnc    OEDone
        call    AddExtention
; file not found error
        mov    dx, offset FileName
        mov    ax, 3d00h
        int    21h
        mov    Handle, ax
        jnc    OEDone

; file does not exist
.file_not_found:
        mov    dx, offset XNameS
        call    Msg
        mov    dx, offset FileName
        call    Msg
        mov    dx, offset NFS
        call    Msg
        jmp    OSExit
OEDone:        ret
OpenExe        endp
        model    small

read_aout    proc    near
        cmp    [bx].a_magic, AoutMagic
        jne    Error
        cmp    [bx].a_CPU, AoutI386
        jne    Error
        mov    dx, offset NotSupported
        call    Msg
        mov    ax, [bx].a_CPU
        shl    eax, 16
        mov    ax, [bx].a_magic
;
        endp
Error        proc    near
        push    ax
        call    hex32
        mov    dx, offset ErrorS
        mov    ax, _DATA
        mov    ds, ax
        pop    ax
        call    Msg
        jmp    OSExit
Error        endp




_TEXT        ends
        end