From a58b2827feceaa27193318a12e3a06893eabdcb6 Mon Sep 17 00:00:00 2001
From: Siva Chandra Reddy <sivachandra@google.com>
Date: Mon, 14 Jun 2021 21:24:57 +0000
Subject: [PATCH] [libc] Add hardware implementations of x86_64 sqrt functions.

---
 libc/src/math/x86_64/CMakeLists.txt | 30 ++++++++++++++++++++++++++++++
 libc/src/math/x86_64/sqrt.cpp       | 20 ++++++++++++++++++++
 libc/src/math/x86_64/sqrtf.cpp      | 20 ++++++++++++++++++++
 libc/src/math/x86_64/sqrtl.cpp      | 20 ++++++++++++++++++++
 4 files changed, 90 insertions(+)
 create mode 100644 libc/src/math/x86_64/sqrt.cpp
 create mode 100644 libc/src/math/x86_64/sqrtf.cpp
 create mode 100644 libc/src/math/x86_64/sqrtl.cpp

diff --git a/libc/src/math/x86_64/CMakeLists.txt b/libc/src/math/x86_64/CMakeLists.txt
index cd129e3..d2a4823 100644
--- a/libc/src/math/x86_64/CMakeLists.txt
+++ b/libc/src/math/x86_64/CMakeLists.txt
@@ -27,3 +27,33 @@ add_entrypoint_object(
   COMPILE_OPTIONS
     -O2
 )
+
+add_entrypoint_object(
+  sqrt
+  SRCS
+    sqrt.cpp
+  HDRS
+    ../sqrt.h
+  COMPILE_OPTIONS
+    -O2
+)
+
+add_entrypoint_object(
+  sqrtf
+  SRCS
+    sqrtf.cpp
+  HDRS
+    ../sqrtf.h
+  COMPILE_OPTIONS
+    -O2
+)
+
+add_entrypoint_object(
+  sqrtl
+  SRCS
+    sqrtl.cpp
+  HDRS
+    ../sqrtl.h
+  COMPILE_OPTIONS
+    -O2
+)
diff --git a/libc/src/math/x86_64/sqrt.cpp b/libc/src/math/x86_64/sqrt.cpp
new file mode 100644
index 0000000..5d4e942
--- /dev/null
+++ b/libc/src/math/x86_64/sqrt.cpp
@@ -0,0 +1,20 @@
+//===-- Implementation of the sqrt function for x86_64 --------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/math/sqrt.h"
+#include "src/__support/common.h"
+
+namespace __llvm_libc {
+
+LLVM_LIBC_FUNCTION(double, sqrt, (double x)) {
+  double result;
+  __asm__ __volatile__("sqrtsd %x1, %x0" : "=x"(result) : "x"(x));
+  return result;
+}
+
+} // namespace __llvm_libc
diff --git a/libc/src/math/x86_64/sqrtf.cpp b/libc/src/math/x86_64/sqrtf.cpp
new file mode 100644
index 0000000..51d22df
--- /dev/null
+++ b/libc/src/math/x86_64/sqrtf.cpp
@@ -0,0 +1,20 @@
+//===-- Implementation of the sqrtf function for x86_64 -------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/math/sqrtf.h"
+#include "src/__support/common.h"
+
+namespace __llvm_libc {
+
+LLVM_LIBC_FUNCTION(float, sqrtf, (float x)) {
+  float result;
+  __asm__ __volatile__("sqrtss %x1, %x0" : "=x"(result) : "x"(x));
+  return result;
+}
+
+} // namespace __llvm_libc
diff --git a/libc/src/math/x86_64/sqrtl.cpp b/libc/src/math/x86_64/sqrtl.cpp
new file mode 100644
index 0000000..8b0c39e
--- /dev/null
+++ b/libc/src/math/x86_64/sqrtl.cpp
@@ -0,0 +1,20 @@
+//===-- Implementation of the sqrtl function for x86_64 -------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/math/sqrtl.h"
+#include "src/__support/common.h"
+
+namespace __llvm_libc {
+
+LLVM_LIBC_FUNCTION(long double, sqrtl, (long double x)) {
+  long double result;
+  __asm__ __volatile__("fsqrt" : "=t"(result) : "t"(x));
+  return result;
+}
+
+} // namespace __llvm_libc
-- 
2.7.4