From f1810c89ea6391c775d9cdf5c612e53dcb870d57 Mon Sep 17 00:00:00 2001
From: Nixitov <Nixitov@users.noreply.github.com>
Date: Mon, 12 Oct 2026 17:29:41 +0200
Subject: [PATCH] feat(libc): implement nearbyintl

OutRun2006 (PPSA99106) imports nearbyintl and stops at start-up on main. Add the long double round-to-nearest-integer export next to nearbyintf; std::nearbyint rounds under the current direction and raises no inexact exception.
---
 core/libs/prx/libc/src/Math.cpp |  1 +
 core/libs/tests/GuestMath.cpp   | 15 +++++++++++++++
 2 files changed, 16 insertions(+)

diff --git a/core/libs/prx/libc/src/Math.cpp b/core/libs/prx/libc/src/Math.cpp
index 9ecf79e14..619b6429d 100644
--- a/core/libs/prx/libc/src/Math.cpp
+++ b/core/libs/prx/libc/src/Math.cpp
@@ -181,6 +181,7 @@ int APS5_VABI __isnormal_nid_postfix(double x) { return std::isnormal(x) ? 1 : 0
 int APS5_VABI __isnormalf_nid_postfix(float x) { return std::isnormal(x) ? 1 : 0; }
 int APS5_VABI __isinff_nid_postfix(float x) { return std::isinf(x) ? 1 : 0; }
 float APS5_VABI nearbyintf_nid_postfix(float x) { return std::nearbyintf(x); }
+long double APS5_VABI nearbyintl_nid_postfix(long double x) { return std::nearbyint(x); }
 
 double APS5_VABI cbrt_nid_postfix(double x) { return std::cbrt(x); }
 double APS5_VABI asin_nid_postfix(double x) {
diff --git a/core/libs/tests/GuestMath.cpp b/core/libs/tests/GuestMath.cpp
index 5a8e85f5f..883c63507 100644
--- a/core/libs/tests/GuestMath.cpp
+++ b/core/libs/tests/GuestMath.cpp
@@ -106,6 +106,7 @@ long double APS5_VABI log10l_nid_postfix(long double);
 long double APS5_VABI powl_nid_postfix(long double, long double);
 long double APS5_VABI ldexpl_nid_postfix(long double, int);
 long double APS5_VABI truncl_nid_postfix(long double);
+long double APS5_VABI nearbyintl_nid_postfix(long double);
 double APS5_VABI logb_nid_postfix(double);
 double APS5_VABI remainder_nid_postfix(double, double);
 }
@@ -192,6 +193,19 @@ static void CheckLongDouble() {
     Require(std::isnan(frexpl_nid_postfix(NAN, &exponent)) && exponent == 77);
 }
 
+static void CheckNearbyintl() {
+    std::feclearexcept(FE_ALL_EXCEPT);
+    const long double zero = nearbyintl_nid_postfix(0.5L);
+    Require(zero == 0.0L && !std::signbit(zero));
+    Require(nearbyintl_nid_postfix(1.5L) == 2.0L && nearbyintl_nid_postfix(2.5L) == 2.0L);
+    Require(nearbyintl_nid_postfix(2.7L) == 3.0L && nearbyintl_nid_postfix(-2.7L) == -3.0L);
+    Require(ExtendedBits(nearbyintl_nid_postfix(-0.5L), 0, 0x8000));
+    Require(nearbyintl_nid_postfix(0x1p200L) == 0x1p200L);
+    Require(nearbyintl_nid_postfix(INFINITY) == INFINITY && nearbyintl_nid_postfix(-INFINITY) == -INFINITY);
+    Require(std::isnan(nearbyintl_nid_postfix(NAN)));
+    Require(std::fetestexcept(FE_INEXACT) == 0);
+}
+
 static void CheckFmodErrno() {
     errno = 0;
     (void)fmod_nid_postfix(1.0, 0.0);
@@ -674,6 +688,7 @@ int main() {
     CheckExp2Errno();
     CheckExactOperations();
     CheckLongDouble();
+    CheckNearbyintl();
     CheckAsinl();
     Require(scalbn_nid_postfix(0.75, -2) == 0.1875);
     Require(scalbnf_nid_postfix(0.75f, 4) == 12.f);