ex-1.1/crt0.s

/ C runtime startoff

/
/ Specially modified for ex to
/ allocate a "glob" buffer at the top of the stack.
/ This buffer is 922 bytes in size (at least) and will
/ thus hold up to 522 chars of arguments and 200 pointers
/ thereto.  It is described by the glob structure (in ex_glob.h).
/
/ Our job here is to set the stack point low enough to leave this
/ space and to initialize the pointer G to point at it.
/ We also put the argc of the main program in the variable
/ xargc0 and the argv thereof in xargv0. This is easier than
/ moving them down the stack.
/

.globl  savr5
.globl  _exit

.globl  _main

.globl  _G, _xargc0, _xargv0

start:
        setd
        mov     sp,r0
        mov     (r0),_xargc0
        tst     (r0)+
        mov     r0,_xargv0
        cmp     $-1024.,sp
        bhi     1f
        mov     $-1024.,sp
1:
        mov     sp,_G
        jmp     _main           / No return
/       jsr     pc,_main
/       cmp     (sp)+,(sp)+
/       mov     r0,(sp)
/       jsr     pc,*$_exit
/       sys     exit

.bss
savr5:  .=.+2