.define _begsig
.sect .text; .sect .rom; .sect .data
.extern _begsig
.extern _vectab, _M
mtype = 2			! M+mtype = &M.m_type
.sect .text
_begsig:
	push ax			! after interrupt, save all regs
	push bx
	push cx
	push dx
	push si
	push di
	push bp
	push ds
	push es
	mov bx,sp
	mov bx,18(bx)		! bx = signal number
	mov ax,bx		! ax = signal number
	dec bx			! vectab[0] is for sig 1
	add bx,bx		! pointers are two bytes on 8088
	mov bx,_vectab(bx)	! bx = address of routine to call
	push (_M+mtype)		! push status of last system call
	push ax			! func called with signal number as arg
	call (bx)
back:
	pop ax			! get signal number off stack
	pop (_M+mtype)		! restore status of previous system call
	pop es			! signal handling finished
	pop ds
	pop bp
	pop di
	pop si
	pop dx
	pop cx
	pop bx
	pop ax
	pop (dummy)		! remove signal number from stack
	iret

.sect .data 
dummy: .data2 0