crt0.asm

Jazmyn is a 32-bit, protected mode, multitasking OS which runs on i386 & above CPU`s. Its complete

;Actually, the program execution doesn`t start with main. This is the small assembly routine
;which pushes the argc, argv & env on the stack & creates the initial stack suitable for the 
;typical 'C' program - main(argc,argv,env).the argv & env will be kept in the start of the
;program heap by the exec() system call & their pointers are kept in ecx & edx respectively.
;ebx is initialized with argc.This startup routine also supports c++.__main is a function which
;calls global object constructors.__atexit which calls global object destructors is called in
;_exit().


[bits 32]			
[global start]
[extern _main]
;[extern __main]
[extern __exit]

start:

	push	edx		;env pointer
	push	ecx		;argv pointer
	push	ebx		;argc

      ;call    __main   ;call global object ctors
	call	_main		;call main(argc,argv,env)
	push	eax		;push the return value of main, if exit() is called in the 
				;program,the control is not reached here
      call    __exit    ;call _exit(), global object dtors are called in _exit

	hlt			;_exit should not return as the process becomes either ZOMBIE
				;or CLEAR & in both cases the process is dead.if some thing
				;goes wrong & _exit returns, halt the cpu.