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| author | Jim Huang <jserv@0xlab.org> | 2011-09-18 07:37:25 +0800 |
|---|---|---|
| committer | Jim Huang <jserv@0xlab.org> | 2011-09-18 10:35:22 +0800 |
| commit | 1cd3559178c691e4f6cea4be85de918afabb033c (patch) | |
| tree | c22fb30923779dd3177780f7e30a6e637e03ee67 /libc/stdio/wcio.h | |
| parent | 69d762d81468aec1b97b39498d0a5e83b05ff44b (diff) | |
| download | android_bionic-1cd3559178c691e4f6cea4be85de918afabb033c.tar.gz android_bionic-1cd3559178c691e4f6cea4be85de918afabb033c.tar.bz2 android_bionic-1cd3559178c691e4f6cea4be85de918afabb033c.zip | |
dlmalloc: Use more efficient ARMv7 implementation for macro compute_bit2idx
The macro compute_bit2idx(X, I) was definied as "I = ffs(X)-1". This
equals to the operation __builtin_ctz(X), and using the new bit-reversal
instruction would have been better for ARMv7:
rbit r0, r0
clz r0, r0
This patch re-implements macro compute_bit2idx by using the above ARMv7
specific instructions to be more efficient.
Reference: http://hardwarebug.org/2010/01/14/beware-the-builtins/
Change-Id: I7cd49da327329c5d75e5e75a557fd115a0c7c0e2
Diffstat (limited to 'libc/stdio/wcio.h')
0 files changed, 0 insertions, 0 deletions