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authorMichael Sevakis <jethead71@rockbox.org>2012-02-04 18:08:17 -0500
committerMichael Sevakis <jethead71@rockbox.org>2012-02-04 18:08:17 -0500
commit67dd4d6995c2bef9910e031f23aae88e07354587 (patch)
tree28ea88021d436a9f7447143757c438af52d1f41d /firmware
parent1a083cdaccb3598de834c3643c5bc02716af804d (diff)
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Generic find_first_set_bit can use __builtin_ctz instead of __builtin_ffsbootloader_clipv2_v5
The former gives 0-based indexes, which is what our implementation returns, making the "- 1" unnecessary. Change-Id: I172ab5e06695be62e4a18d4fd0415b8314f5dc26
Diffstat (limited to 'firmware')
-rw-r--r--firmware/asm/ffs.c7
1 files changed, 4 insertions, 3 deletions
diff --git a/firmware/asm/ffs.c b/firmware/asm/ffs.c
index 6826f42e94..a4512e0c55 100644
--- a/firmware/asm/ffs.c
+++ b/firmware/asm/ffs.c
@@ -35,7 +35,8 @@ int find_first_set_bit(uint32_t val)
if (val == 0)
return 32;
- /* __builtin_ffs(l(l)): Returns one plus the index of the least significant
- 1-bit of x, or if x is zero, returns zero. */
- return __builtin_ffs(val) - 1;
+ /* __builtin_ctz[l[l]]: Returns the number of trailing 0-bits in x,
+ * starting at the least significant bit position. If x is 0, the result
+ * is undefined. */
+ return __builtin_ctz(val);
}