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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/stdlib/__exp10.c
parent58c860d6c48324eba66dd19540db5584d832cf58 (diff)
parentd88495e3f4061a411e654c7307aa94ac8a98c94b (diff)
Merge pull request #13 from ProjectRevoTPP/libc
add libc building to agbcc.
Diffstat (limited to 'libc/stdlib/__exp10.c')
-rw-r--r--libc/stdlib/__exp10.c29
1 files changed, 29 insertions, 0 deletions
diff --git a/libc/stdlib/__exp10.c b/libc/stdlib/__exp10.c
new file mode 100644
index 0000000..9673623
--- /dev/null
+++ b/libc/stdlib/__exp10.c
@@ -0,0 +1,29 @@
+/*
+ * compute 10**x by successive squaring.
+ */
+
+#include <_ansi.h>
+
+double
+_DEFUN (__exp10, (x),
+ unsigned x)
+{
+ static _CONST double powtab[] =
+ {1.0,
+ 10.0,
+ 100.0,
+ 1000.0,
+ 10000.0};
+
+ if (x < (sizeof (powtab) / sizeof (double)))
+ return powtab[x];
+ else if (x & 1)
+ {
+ return 10.0 * __exp10 (x - 1);
+ }
+ else
+ {
+ double n = __exp10 (x / 2);
+ return n * n;
+ }
+}