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authorMarcus Huderle <huderlem@gmail.com>2017-12-27 16:22:00 -0600
committerGitHub <noreply@github.com>2017-12-27 16:22:00 -0600
commit6b611a3046a694d3972f2aa4df90d3ef78801217 (patch)
tree05f295c00cbbc1d5987a05da37e746fb841d4d83 /libc/misc/ffs.c
parent58c860d6c48324eba66dd19540db5584d832cf58 (diff)
parentd88495e3f4061a411e654c7307aa94ac8a98c94b (diff)
Merge pull request #13 from ProjectRevoTPP/libc
add libc building to agbcc.
Diffstat (limited to 'libc/misc/ffs.c')
-rw-r--r--libc/misc/ffs.c42
1 files changed, 42 insertions, 0 deletions
diff --git a/libc/misc/ffs.c b/libc/misc/ffs.c
new file mode 100644
index 0000000..e4afe7a
--- /dev/null
+++ b/libc/misc/ffs.c
@@ -0,0 +1,42 @@
+/*
+FUNCTION
+ <<ffs>>---find first bit set in a word
+
+INDEX
+ ffs
+
+ANSI_SYNOPSIS
+ int ffs(int <[word]>);
+
+TRAD_SYNOPSIS
+ int ffs(<[word]>);
+
+DESCRIPTION
+
+<<ffs>> returns the first bit set in a word.
+
+RETURNS
+<<ffs>> returns 0 if <[c]> is 0, 1 if <[c]> is odd, 2 if <[c]> is a multiple of
+2, etc.
+
+PORTABILITY
+<<ffs>> is not ANSI C.
+
+No supporting OS subroutines are required. */
+
+int
+ffs (word)
+ int word;
+{
+ int i;
+
+ if (!word)
+ return 0;
+
+ i = 0;
+ for (;;)
+ {
+ if (((1 << i++) & word) != 0)
+ return i;
+ }
+}