From 915dea01c96004b84588f084b6a4166aae2cd024 Mon Sep 17 00:00:00 2001
From: Bananymous <oskari.alaranta@bananymous.com>
Date: Fri, 16 Feb 2024 15:34:24 +0200
Subject: [PATCH] LibC: fix printf %e for inf/nan values

---
 libc/printf_impl.cpp | 27 ++++++++++++++++-----------
 1 file changed, 16 insertions(+), 11 deletions(-)

diff --git a/libc/printf_impl.cpp b/libc/printf_impl.cpp
index 040b786df1..85524a6f05 100644
--- a/libc/printf_impl.cpp
+++ b/libc/printf_impl.cpp
@@ -122,17 +122,6 @@ static void integer_to_string(char* buffer, T value, int base, bool upper, forma
 template<BAN::floating_point T>
 static void floating_point_to_string(char* buffer, T value, bool upper, const format_options_t options)
 {
-	if (isnan(value))
-	{
-		if (value < (T)0.0)
-		{
-			*buffer = '-';
-			buffer++;
-		}
-		strcpy(buffer, upper ? "NAN" : "nan");
-		return;
-	}
-
 	int percision = 6;
 	if (options.percision != -1)
 		percision = options.percision;
@@ -150,6 +139,11 @@ static void floating_point_to_string(char* buffer, T value, bool upper, const fo
 	else if (options.show_plus_sign_as_space)
 		buffer[offset++] = ' ';
 
+	if (isnan(value))
+	{
+		strcpy(buffer + offset, upper ? "NAN" : "nan");
+		return;
+	}
 	if (isinf(value))
 	{
 		strcpy(buffer + offset, upper ? "INF" : "inf");
@@ -223,6 +217,17 @@ static void floating_point_to_exponent_string(char* buffer, T value, bool upper,
 	else if (options.show_plus_sign_as_space)
 		buffer[offset++] = ' ';
 
+	if (isnan(value))
+	{
+		strcpy(buffer + offset, upper ? "NAN" : "nan");
+		return;
+	}
+	if (isinf(value))
+	{
+		strcpy(buffer + offset, upper ? "INF" : "inf");
+		return;
+	}
+
 	// Calculate which number to put as exponent
 	int exponent = 0;
 	if (value != (T)0.0)