Date: 10 Dec 88 05:30:51 GMT
Comment:  Extracted from Info-Atari16 (INFO-A16) digest number 88-???
From: portal!cup.portal.com!Thomas_E_Zerucha@uunet.uu.net
Subject: Re: Setting default environment from auto folder
To: info-atari16@score.stanford.edu

I managed to do it - it was fairly simple, but what you have to do is find
the pointer in the environment of the parent of the process from the auto
folder (or the parent of the parent - the one that the desktop gets).

A short assembly program follows (the one I use)

---cut here---
    .text
*housekeeping
    move.l    a7,a5
    move.l    4(a5),a5    ;compute size for TSR call
    move.l    $c(a5),d6    ;text
    add.l    $14(a5),d6    ;data
    add.l    $1c(a5),d6    ;bss
    add.l    #$100,d6    ;basepage
    add.l    #$40,d6        ;saftey
* alter vector
    move.l    #doit,-(sp)    ;point to the vector changer code
    move.w    #38,-(sp)    ;we want to do it in supervisor mode!
    trap    #14        ;execute it!
    addq.l    #6,sp
* tell everyone we are here
    pea    msg1
    move.w    #9,-(sp)
    trap    #1
    addq.l    #6,sp
* TSR
    clr    -(sp)        ;exit but stay
    move.l    d6,-(sp)
    move    #$31,-(sp)
    trap    #1

bexit:    move    #0,-(sp)
    trap    #1
* set env upon startup
movenv:
    move.l    a7,a5
    move.l    4(a5),a5
    move.l    a5,a4
linkup:
    move.l    $24(a4),a4
    movea.l    $2c(a4),a3
    cmp.w    #0,(a3)
    beq.s    setwork
    move.l    a4,a5
    bra.s    linkup
setwork:

    move.l    #workar,$2c(a5)
    move.l    shlsav,a5
    jmp    (a5)
***
* install (in super) vector
doit:    move.l    $4fe,shlsav    ;move
    move.l    #movenv,$4fe    ;move
    rts                     ;and return
***
*************************
    .data
msg1:        dc.b    'GEM Resource Path Set\r\n',0
shlsav:        dc.l    0
workar:    dc.b    'PATH=;D:\\RESOURCE;D:\\;D:\\BIN'
    dc.b    ';d:\\LANG;D:\\SCRIPTS;D:\\USRBIN;.',0
    dc.b    'TEMP=c:\\tmp\\',0
    dc.b    'INCLUDE=d:\\include\\',0
    dc.b    'SYMB=d:\\lang\\',0
    dc.b    'LIB=d:\\lib\\',0
    dc.b    'STARTUP=d:\\lib\\gemstart',0
    dc.b    'RUNTIME=d:\\lib\\gemlib',0
    dc.b    'SUFF=,.prg,.ttp,.tos',0
    dc.b    'LIBPATH=d:\\mwlib,d:\\lang,.',0
    dc.b    'INCDIR=d:\\mwinc\\',0
    dc.b    'TMPDIR=c:\\tmp\\',0
    dc.b    'TIMEZONE=EST:0:EDT',0
    dc.b    'M2SBM=d:\\modlibs',0
    dc.b    'M2OBM=d:\\modlibs',0
    dc.b    'EDITOR=stedt.ttp',0
        dc.b    'SEDT=d:\\include\\',0
    dc.b    'SHELL=csh.tos',0
    dc.b    0,0

    .end

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