From 29adaeb2c0e795e75044a9b678b8cc66570f7e95 Mon Sep 17 00:00:00 2001
From: Alexander Monakov <amonakov@ispras.ru>
Date: Mon, 6 Jan 2020 20:31:47 +0300
Subject: math: move i386 sqrtf to C with inline asm
---
src/math/i386/sqrtf.c | 12 ++++++++++++
src/math/i386/sqrtf.s | 7 -------
2 files changed, 12 insertions(+), 7 deletions(-)
create mode 100644 src/math/i386/sqrtf.c
delete mode 100644 src/math/i386/sqrtf.s
(limited to 'src/math')
diff --git a/src/math/i386/sqrtf.c b/src/math/i386/sqrtf.c
new file mode 100644
index 00000000..41c65c2b
--- /dev/null
+++ b/src/math/i386/sqrtf.c
@@ -0,0 +1,12 @@
+#include <math.h>
+
+float sqrtf(float x)
+{
+ long double t;
+ /* The long double result has sufficient precision so that
+ * second rounding to float still keeps the returned value
+ * correctly rounded, see Pierre Roux, "Innocuous Double
+ * Rounding of Basic Arithmetic Operations". */
+ __asm__ ("fsqrt" : "=t"(t) : "0"(x));
+ return (float)t;
+}
diff --git a/src/math/i386/sqrtf.s b/src/math/i386/sqrtf.s
deleted file mode 100644
index 9e944f45..00000000
--- a/src/math/i386/sqrtf.s
+++ /dev/null
@@ -1,7 +0,0 @@
-.global sqrtf
-.type sqrtf,@function
-sqrtf: flds 4(%esp)
- fsqrt
- fstps 4(%esp)
- flds 4(%esp)
- ret
--
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