[unix-history] / usr / src / old / sh / stak.h

/*	stak.h	4.1	82/05/07	*/

#
/*
 *	UNIX shell
 *
 *	S. R. Bourne
 *	Bell Telephone Laboratories
 *
 */

/* To use stack as temporary workspace across
 * possible storage allocation (eg name lookup)
 * a) get ptr from `relstak'
 * b) can now use `pushstak'
 * c) then reset with `setstak'
 * d) `absstak' gives real address if needed
 */
#define		relstak()	(staktop-stakbot)
#define		absstak(x)	(stakbot+Rcheat(x))
#define		setstak(x)	(staktop=absstak(x))
#define		pushstak(c)	(*staktop++=(c))
#define		zerostak()	(*staktop=0)

/* Used to address an item left on the top of
 * the stack (very temporary)
 */
#define		curstak()	(staktop)

/* `usestak' before `pushstak' then `fixstak'
 * These routines are safe against heap
 * being allocated.
 */
#define		usestak()	{locstak();}

/* for local use only since it hands
 * out a real address for the stack top
 */
STKPTR		locstak();

/* Will allocate the item being used and return its
 * address (safe now).
 */
#define		fixstak()	endstak(staktop)

/* For use after `locstak' to hand back
 * new stack top and then allocate item
 */
STKPTR		endstak();

/* Copy a string onto the stack and
 * allocate the space.
 */
STKPTR		cpystak();

/* Allocate given ammount of stack space */
STKPTR		getstak();

/* A chain of ptrs of stack blocks that
 * have become covered by heap allocation.
 * `tdystak' will return them to the heap.
 */
BLKPTR		stakbsy;

/* Base of the entire stack */
STKPTR		stakbas;

/* Top of entire stack */
STKPTR		brkend;

/* Base of current item */
STKPTR		stakbot;

/* Top of current item */
STKPTR		staktop;

/* Used with tdystak */
STKPTR		savstak();
Commit	Line	Data
5bd35864 KM	1	/* stak.h 4.1 82/05/07 */
	2
	3	#
	4	/*
	5	* UNIX shell
	6	*
	7	* S. R. Bourne
	8	* Bell Telephone Laboratories
	9	*
	10	*/
	11
	12	/* To use stack as temporary workspace across
	13	* possible storage allocation (eg name lookup)
	14	* a) get ptr from `relstak'
	15	* b) can now use `pushstak'
	16	* c) then reset with `setstak'
	17	* d) `absstak' gives real address if needed
	18	*/
	19	#define relstak() (staktop-stakbot)
	20	#define absstak(x) (stakbot+Rcheat(x))
	21	#define setstak(x) (staktop=absstak(x))
	22	#define pushstak(c) (*staktop++=(c))
	23	#define zerostak() (*staktop=0)
	24
	25	/* Used to address an item left on the top of
	26	* the stack (very temporary)
	27	*/
	28	#define curstak() (staktop)
	29
	30	/* `usestak' before `pushstak' then `fixstak'
	31	* These routines are safe against heap
	32	* being allocated.
	33	*/
	34	#define usestak() {locstak();}
	35
	36	/* for local use only since it hands
	37	* out a real address for the stack top
	38	*/
	39	STKPTR locstak();
	40
	41	/* Will allocate the item being used and return its
	42	* address (safe now).
	43	*/
	44	#define fixstak() endstak(staktop)
	45
	46	/* For use after `locstak' to hand back
	47	* new stack top and then allocate item
	48	*/
	49	STKPTR endstak();
	50
	51	/* Copy a string onto the stack and
	52	* allocate the space.
	53	*/
	54	STKPTR cpystak();
	55
	56	/* Allocate given ammount of stack space */
	57	STKPTR getstak();
	58
	59	/* A chain of ptrs of stack blocks that
	60	* have become covered by heap allocation.
	61	* `tdystak' will return them to the heap.
	62	*/
	63	BLKPTR stakbsy;
	64
65	/* Base of the entire stack */
66	STKPTR stakbas;
67
68	/* Top of entire stack */
69	STKPTR brkend;
70
71	/* Base of current item */
72	STKPTR stakbot;
73
74	/* Top of current item */
75	STKPTR staktop;
76
77	/* Used with tdystak */
78	STKPTR savstak();