xref: /openbmc/linux/arch/sparc/lib/fls64.S (revision be709d48)
1/* fls64.S: SPARC default __fls definition.
2 *
3 * SPARC default __fls definition, which follows the same algorithm as
4 * in generic __fls(). This function will be boot time patched on T4
5 * and onward.
6 */
7
8#include <linux/linkage.h>
9#include <asm/export.h>
10
11	.text
12	.register	%g2, #scratch
13	.register	%g3, #scratch
14ENTRY(__fls)
15	mov	-1, %g2
16	sllx	%g2, 32, %g2
17	and	%o0, %g2, %g2
18	brnz,pt	%g2, 1f
19	 mov	63, %g1
20	sllx	%o0, 32, %o0
21	mov	31, %g1
221:
23	mov	-1, %g2
24	sllx	%g2, 48, %g2
25	and	%o0, %g2, %g2
26	brnz,pt	%g2, 2f
27	 mov	-1, %g2
28	sllx	%o0, 16, %o0
29	add	%g1, -16, %g1
302:
31	mov	-1, %g2
32	sllx	%g2, 56, %g2
33	and	%o0, %g2, %g2
34	brnz,pt	%g2, 3f
35	 mov	-1, %g2
36	sllx	%o0, 8, %o0
37	add	%g1, -8, %g1
383:
39	sllx	%g2, 60, %g2
40	and	%o0, %g2, %g2
41	brnz,pt	%g2, 4f
42	 mov	-1, %g2
43	sllx	%o0, 4, %o0
44	add	%g1, -4, %g1
454:
46	sllx	%g2, 62, %g2
47	and	%o0, %g2, %g2
48	brnz,pt	%g2, 5f
49	 mov	-1, %g3
50	sllx	%o0, 2, %o0
51	add	%g1, -2, %g1
525:
53	mov	0, %g2
54	sllx	%g3, 63, %g3
55	and	%o0, %g3, %o0
56	movre	%o0, 1, %g2
57	sub	%g1, %g2, %g1
58	jmp	%o7+8
59	 sra	%g1, 0, %o0
60ENDPROC(__fls)
61EXPORT_SYMBOL(__fls)
62