From 30634165980deaeead9f4e71e0ff6a5c9d897776 Mon Sep 17 00:00:00 2001
From: Ian Moffett <ian@osmora.org>
Date: Mon, 14 Jul 2025 22:39:34 -0400
Subject: usr: libc: Add math.h + musl math impl port

Signed-off-by: Ian Moffett <ian@osmora.org>
---
 lib/libc/src/musl-math/logb.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)
 create mode 100644 lib/libc/src/musl-math/logb.c

(limited to 'lib/libc/src/musl-math/logb.c')

diff --git a/lib/libc/src/musl-math/logb.c b/lib/libc/src/musl-math/logb.c
new file mode 100644
index 0000000..7f8bdfa
--- /dev/null
+++ b/lib/libc/src/musl-math/logb.c
@@ -0,0 +1,17 @@
+#include <math.h>
+
+/*
+special cases:
+	logb(+-0) = -inf, and raise divbyzero
+	logb(+-inf) = +inf
+	logb(nan) = nan
+*/
+
+double logb(double x)
+{
+	if (!isfinite(x))
+		return x * x;
+	if (x == 0)
+		return -1/(x*x);
+	return ilogb(x);
+}
-- 
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