From 698f8c2f01ea549d77d7dc3338a12e04c11057b9 Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Wed, 17 Apr 2024 14:02:58 +0200
Subject: Adding upstream version 1.64.0+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 vendor/compiler_builtins/libm/src/math/fmaf.rs | 106 +++++++++++++++++++++++++
 1 file changed, 106 insertions(+)
 create mode 100644 vendor/compiler_builtins/libm/src/math/fmaf.rs

(limited to 'vendor/compiler_builtins/libm/src/math/fmaf.rs')

diff --git a/vendor/compiler_builtins/libm/src/math/fmaf.rs b/vendor/compiler_builtins/libm/src/math/fmaf.rs
new file mode 100644
index 000000000..03d371c55
--- /dev/null
+++ b/vendor/compiler_builtins/libm/src/math/fmaf.rs
@@ -0,0 +1,106 @@
+/* origin: FreeBSD /usr/src/lib/msun/src/s_fmaf.c */
+/*-
+ * Copyright (c) 2005-2011 David Schultz <das@FreeBSD.ORG>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+use core::f32;
+use core::ptr::read_volatile;
+
+use super::fenv::{
+    feclearexcept, fegetround, feraiseexcept, fesetround, fetestexcept, FE_INEXACT, FE_TONEAREST,
+    FE_TOWARDZERO, FE_UNDERFLOW,
+};
+
+/*
+ * Fused multiply-add: Compute x * y + z with a single rounding error.
+ *
+ * A double has more than twice as much precision than a float, so
+ * direct double-precision arithmetic suffices, except where double
+ * rounding occurs.
+ */
+
+/// Floating multiply add (f32)
+///
+/// Computes `(x*y)+z`, rounded as one ternary operation:
+/// Computes the value (as if) to infinite precision and rounds once to the result format,
+/// according to the rounding mode characterized by the value of FLT_ROUNDS.
+#[cfg_attr(all(test, assert_no_panic), no_panic::no_panic)]
+pub fn fmaf(x: f32, y: f32, mut z: f32) -> f32 {
+    let xy: f64;
+    let mut result: f64;
+    let mut ui: u64;
+    let e: i32;
+
+    xy = x as f64 * y as f64;
+    result = xy + z as f64;
+    ui = result.to_bits();
+    e = (ui >> 52) as i32 & 0x7ff;
+    /* Common case: The double precision result is fine. */
+    if (
+        /* not a halfway case */
+        ui & 0x1fffffff) != 0x10000000 ||
+        /* NaN */
+        e == 0x7ff ||
+        /* exact */
+        (result - xy == z as f64 && result - z as f64 == xy) ||
+        /* not round-to-nearest */
+        fegetround() != FE_TONEAREST
+    {
+        /*
+            underflow may not be raised correctly, example:
+            fmaf(0x1p-120f, 0x1p-120f, 0x1p-149f)
+        */
+        if e < 0x3ff - 126 && e >= 0x3ff - 149 && fetestexcept(FE_INEXACT) != 0 {
+            feclearexcept(FE_INEXACT);
+            // prevent `xy + vz` from being CSE'd with `xy + z` above
+            let vz: f32 = unsafe { read_volatile(&z) };
+            result = xy + vz as f64;
+            if fetestexcept(FE_INEXACT) != 0 {
+                feraiseexcept(FE_UNDERFLOW);
+            } else {
+                feraiseexcept(FE_INEXACT);
+            }
+        }
+        z = result as f32;
+        return z;
+    }
+
+    /*
+     * If result is inexact, and exactly halfway between two float values,
+     * we need to adjust the low-order bit in the direction of the error.
+     */
+    fesetround(FE_TOWARDZERO);
+    // prevent `vxy + z` from being CSE'd with `xy + z` above
+    let vxy: f64 = unsafe { read_volatile(&xy) };
+    let mut adjusted_result: f64 = vxy + z as f64;
+    fesetround(FE_TONEAREST);
+    if result == adjusted_result {
+        ui = adjusted_result.to_bits();
+        ui += 1;
+        adjusted_result = f64::from_bits(ui);
+    }
+    z = adjusted_result as f32;
+    z
+}
-- 
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