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linux-next/arch/sparc/lib/fls.S
Vijay Kumar 41413a6035 sparc64: Define SPARC default fls function
fls will now require a boot time patching on T4 and above.
Redefining it under arch/sparc/lib.

Signed-off-by: Vijay Kumar <vijay.ac.kumar@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-11-15 14:26:45 +09:00

68 lines
1.2 KiB
ArmAsm

/* fls.S: SPARC default fls definition.
*
* SPARC default fls definition, which follows the same algorithm as
* in generic fls(). This function will be boot time patched on T4
* and onward.
*/
#include <linux/linkage.h>
#include <asm/export.h>
.text
.register %g2, #scratch
.register %g3, #scratch
ENTRY(fls)
brz,pn %o0, 6f
mov 0, %o1
sethi %hi(0xffff0000), %g3
mov %o0, %g2
andcc %o0, %g3, %g0
be,pt %icc, 8f
mov 32, %o1
sethi %hi(0xff000000), %g3
andcc %g2, %g3, %g0
bne,pt %icc, 3f
sethi %hi(0xf0000000), %g3
sll %o0, 8, %o0
1:
add %o1, -8, %o1
sra %o0, 0, %o0
mov %o0, %g2
2:
sethi %hi(0xf0000000), %g3
3:
andcc %g2, %g3, %g0
bne,pt %icc, 4f
sethi %hi(0xc0000000), %g3
sll %o0, 4, %o0
add %o1, -4, %o1
sra %o0, 0, %o0
mov %o0, %g2
4:
andcc %g2, %g3, %g0
be,a,pt %icc, 7f
sll %o0, 2, %o0
5:
xnor %g0, %o0, %o0
srl %o0, 31, %o0
sub %o1, %o0, %o1
6:
jmp %o7 + 8
sra %o1, 0, %o0
7:
add %o1, -2, %o1
ba,pt %xcc, 5b
sra %o0, 0, %o0
8:
sll %o0, 16, %o0
sethi %hi(0xff000000), %g3
sra %o0, 0, %o0
mov %o0, %g2
andcc %g2, %g3, %g0
bne,pt %icc, 2b
mov 16, %o1
ba,pt %xcc, 1b
sll %o0, 8, %o0
ENDPROC(fls)
EXPORT_SYMBOL(fls)