146 lines
2.5 KiB
ArmAsm
146 lines
2.5 KiB
ArmAsm
|
#
|
||
|
|
! $Source$
|
||
|
|
! $State$
|
||
|
|
! $Revision$
|
||
|
|
|
||
|
|
! Declare segments (the order is important).
|
||
|
|
|
||
|
|
.sect .text
|
||
|
|
.sect .rom
|
||
|
|
.sect .data
|
||
|
|
.sect .bss
|
||
|
|
|
||
|
|
.sect .text
|
||
|
|
|
||
|
|
begtext:
|
||
|
|
! Make sure we are running under MS-DOS 2 or above.
|
||
|
|
!
|
||
|
|
! While at it, also remember the actual DOS version, so that we know
|
||
|
|
! whether DOS gives us the program's name in the environment
|
||
|
|
! segment. (DOS 3+ does; DOS 2.x does not.)
|
||
|
|
movb ah, 0x30
|
||
|
|
int 0x21
|
||
|
|
cmpb al, 2
|
||
|
|
xchg bx, ax
|
||
|
|
jc bad_sys
|
||
|
|
|
||
|
|
! Clear BSS.
|
||
|
|
mov di, begbss
|
||
|
|
mov cx, endbss+1
|
||
|
|
sub cx, di
|
||
|
|
shr cx, 1
|
||
|
|
xor ax, ax
|
||
|
|
cld
|
||
|
|
rep stosw
|
||
|
|
|
||
|
|
! Get the size of the environment variables plus (if present) the
|
||
|
|
! program name. Also count the number of environment variables.
|
||
|
|
mov es, (0x002C)
|
||
|
|
xor di, di
|
||
|
|
! ax = 0 from above
|
||
|
|
cwd ! dx = count of env. vars.
|
||
|
|
mov cx, -1
|
||
|
|
scasb ! handle special case of empty env.
|
||
|
|
jz is_empty_env
|
||
|
|
size_env:
|
||
|
|
inc dx
|
||
|
|
repnz scasb
|
||
|
|
scasb
|
||
|
|
jnz size_env
|
||
|
|
is_empty_env:
|
||
|
|
cmpb bl, 2
|
||
|
|
jz no_argv0
|
||
|
|
scasw
|
||
|
|
repnz scasb
|
||
|
|
no_argv0:
|
||
|
|
|
||
|
|
! Copy out the environment variables and (possibly) program name
|
||
|
|
! onto the stack.
|
||
|
|
mov si, di
|
||
|
|
dec si
|
||
|
|
and si, -2
|
||
|
|
std
|
||
|
|
copy_env:
|
||
|
|
test si, si
|
||
|
|
eseg lodsw
|
||
|
|
push ax
|
||
|
|
jnz copy_env
|
||
|
|
mov cx, sp
|
||
|
|
|
||
|
|
! Reset DF and es properly.
|
||
|
|
cld
|
||
|
|
push ss
|
||
|
|
pop es
|
||
|
|
|
||
|
|
! Reserve space for argc and the argv and envp pointers on the
|
||
|
|
! stack. These will be passed to __m_a_i_n later.
|
||
|
|
sub sp, 6
|
||
|
|
mov ax, sp
|
||
|
|
|
||
|
|
! Build up argc, argv[], and envp[].
|
||
|
|
push ax ! output buffer for argc, argv, envp
|
||
|
|
push bx ! MS-DOS version
|
||
|
|
push cx ! env. string data
|
||
|
|
push dx ! count of env. vars.
|
||
|
|
mov ax, 0x0080
|
||
|
|
push ax ! raw command line
|
||
|
|
call __sys_initmain
|
||
|
|
add sp, 10
|
||
|
|
|
||
|
|
! Bail out if something went wrong.
|
||
|
|
test ax, ax
|
||
|
|
jnz no_room
|
||
|
|
|
||
|
|
! argc, argv, and envp are now at the stack top. Now go.
|
||
|
|
call __m_a_i_n
|
||
|
|
add sp, 6
|
||
|
|
push ax
|
||
|
|
call _exit
|
||
|
|
|
||
|
|
bad_sys:
|
||
|
|
mov dx, bad_sys_msg
|
||
|
|
dos_msg:
|
||
|
|
movb ah, 9
|
||
|
|
int 0x21
|
||
|
|
ret
|
||
|
|
|
||
|
|
no_room:
|
||
|
|
mov dx, no_room_msg
|
||
|
|
call dos_msg
|
||
|
|
movb al, -1
|
||
|
|
jmp al_exit
|
||
|
|
|
||
|
|
! Exit.
|
||
|
|
.define __exit
|
||
|
|
.extern __exit
|
||
|
|
.define EXIT
|
||
|
|
.extern EXIT
|
||
|
|
__exit:
|
||
|
|
EXIT:
|
||
|
|
pop bx
|
||
|
|
pop ax
|
||
|
|
al_exit:
|
||
|
|
movb ah, 0x4c
|
||
|
|
int 0x21
|
||
|
|
|
||
|
|
! Define symbols at the beginning of our various segments, so that we can find
|
||
|
|
! them. (Except .text, which has already been done.)
|
||
|
|
|
||
|
|
.define begtext, begdata, begbss
|
||
|
|
.sect .data; begdata:
|
||
|
|
.sect .rom; begrom:
|
||
|
|
.sect .bss; begbss:
|
||
|
|
|
||
|
|
.sect .rom
|
||
|
|
|
||
|
|
! Some text messages.
|
||
|
|
bad_sys_msg: .ascii 'Bad DOS$'
|
||
|
|
no_room_msg: .ascii 'No room$'
|
||
|
|
|
||
|
|
! Some magic data. All EM systems need these.
|
||
|
|
|
||
|
|
.define .trppc, .ignmask, _errno
|
||
|
|
.comm .trppc, 4
|
||
|
|
.comm .ignmask, 4
|
||
|
|
.comm _errno, 4
|