From cd527bb324ade952d11a134859d38bf5272c165e Mon Sep 17 00:00:00 2001
From: Damien George <damien.p.george@gmail.com>
Date: Thu, 3 Nov 2016 12:26:32 +1100
Subject: [PATCH] lib/libm: Move Thumb-specific sqrtf function to separate
 file.

This allows it to be used only when the hardware supports VFP
instructions, preventing compile errors.
---
 lib/libm/math.c            | 13 -------------
 lib/libm/thumb_vfp_sqrtf.c | 11 +++++++++++
 stmhal/Makefile            |  1 +
 3 files changed, 12 insertions(+), 13 deletions(-)
 create mode 100644 lib/libm/thumb_vfp_sqrtf.c

diff --git a/lib/libm/math.c b/lib/libm/math.c
index 7cbec5fb3..732049236 100644
--- a/lib/libm/math.c
+++ b/lib/libm/math.c
@@ -86,19 +86,6 @@ double __aeabi_dmul(double x , double y) {
 
 #endif // defined(__thumb__)
 
-// TODO this needs a better way of testing for Thumb2 FP hardware
-#if defined(__thumb2__)
-
-float sqrtf(float x) {
-    asm volatile (
-            "vsqrt.f32  %[r], %[x]\n"
-            : [r] "=t" (x)
-            : [x] "t"  (x));
-    return x;
-}
-
-#endif
-
 #ifndef NDEBUG
 float copysignf(float x, float y) {
     float_s_t fx={.f = x};
diff --git a/lib/libm/thumb_vfp_sqrtf.c b/lib/libm/thumb_vfp_sqrtf.c
new file mode 100644
index 000000000..12ffebf82
--- /dev/null
+++ b/lib/libm/thumb_vfp_sqrtf.c
@@ -0,0 +1,11 @@
+// an implementation of sqrtf for Thumb using hardware VFP instructions
+
+#include <math.h>
+
+float sqrtf(float x) {
+    asm volatile (
+            "vsqrt.f32  %[r], %[x]\n"
+            : [r] "=t" (x)
+            : [x] "t"  (x));
+    return x;
+}
diff --git a/stmhal/Makefile b/stmhal/Makefile
index e2e1dc6a1..a7a3018cc 100644
--- a/stmhal/Makefile
+++ b/stmhal/Makefile
@@ -81,6 +81,7 @@ endif
 SRC_LIB = $(addprefix lib/,\
 	libc/string0.c \
 	libm/math.c \
+	libm/thumb_vfp_sqrtf.c \
 	libm/asinfacosf.c \
 	libm/atanf.c \
 	libm/atan2f.c \