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SETIPL.S@ 6099cac

Last change on this file since 6099cac was 3ae31e9, checked in by Thomas Lopatic <thomas@…>, 8 years ago
Imported original source code.
Property mode set to `100755`
File size: 1.2 KB

Line
1	*
2	* setipl.s -- Set internal processor interrupt level
3	* -------- --------------------------------------
4	* Version 2 -- 1988-06-29 -- D.N. Lynx Crowe
5	*
6	* short
7	* setipl(arg);
8	* short arg;
9	*
10	* Sets processor interrupt level to arg.
11	* Returns old interrupt level, or -1 if arg < 0 or > 7
12	*
13	* Assumes you are in supervisor mode.
14	* You get a Privelege Violation TRAP if you aren't.
15	*
16	.text
17	*
18	.xdef _setipl
19	*
20	_setipl: link a6,#0 * Link up stack frames
21	move.w 8(a6),d0 * Get argument
22	tst.w d0 * Check lower limit
23	bmi setipler * Jump if < 0 (error)
24	*
25	cmpi.w #7,d0 * Check upper limit
26	bgt setipler * Jump if > 7 (error)
27	*
28	move.w sr,d1 * Get current level
29	move.w d1,d2 * ... save for later
30	lsl.w #8,d0 * Shift argument into position
31	andi.w #$F8FF,d1 * Mask out old level
32	or.w d0,d1 * OR in new level
33	move.w d2,d0 * Setup return of old level
34	lsr.w #8,d0 * ...
35	andi.l #$7,d0 * ...
36	move.w d1,sr * Set the new interrupt level
37	unlk a6 * Unlink stack frames
38	rts * Return to caller
39	*
40	setipler: moveq.l #-1,d0 * Setup to return error code
41	unlk a6 * Unlink stack frames
42	rts * Return to caller
43	*
44	.end

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