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| author | cognet <cognet@FreeBSD.org> | 2004-11-07 16:53:29 +0000 |
|---|---|---|
| committer | cognet <cognet@FreeBSD.org> | 2004-11-07 16:53:29 +0000 |
| commit | 964bf9d8f7224bc91023df9f0e4ed3694db44c62 (patch) | |
| tree | c2bf97e8288c64fd6d5ab204bf6991c1c9a49545 /sys/libkern | |
| parent | ce94b57ab1d34bc9fbee57209be44b713c7f9104 (diff) | |
| download | FreeBSD-src-964bf9d8f7224bc91023df9f0e4ed3694db44c62.zip FreeBSD-src-964bf9d8f7224bc91023df9f0e4ed3694db44c62.tar.gz | |
Implement ffs with clz for Xscale.
Idea taken from: NetBSD
Diffstat (limited to 'sys/libkern')
| -rw-r--r-- | sys/libkern/arm/ffs.S | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/sys/libkern/arm/ffs.S b/sys/libkern/arm/ffs.S index 4e6fe3d..6fe31b9 100644 --- a/sys/libkern/arm/ffs.S +++ b/sys/libkern/arm/ffs.S @@ -46,9 +46,12 @@ __FBSDID("$FreeBSD$"); */ ENTRY(ffs) + /* Standard trick to isolate bottom bit in r0 or 0 if r0 = 0 on entry */ rsb r1, r0, #0 ands r0, r0, r1 +#ifndef __XSCALE__ + /* * now r0 has at most one set bit, call this X * if X = 0, all further instructions are skipped @@ -74,4 +77,8 @@ ENTRY(ffs) .byte 10, 0, 0, 25, 0, 0, 21, 27 /* 40-47 */ .byte 31, 0, 0, 0, 0, 24, 0, 20 /* 48-55 */ .byte 30, 0, 23, 19, 29, 18, 17, 0 /* 56-63 */ - +#else + clzne r0, r0 + rsbne r0, r0, #32 + mov pc, lr +#endif |
