lib/libc/minimal: Move sqrt/sqrtf from samples
The lmp90100_evb sample included an implementation of double sqrt, and the
on_off_level_lighting_vnd_app sample included an implementation of float
sqrtf. Move that code into minimal libc instead of requiring applications
to hand-roll their own version.
Signed-off-by: Keith Packard <keithp@keithp.com>
diff --git a/lib/libc/minimal/CMakeLists.txt b/lib/libc/minimal/CMakeLists.txt
index f8f5968..827c1c8 100644
--- a/lib/libc/minimal/CMakeLists.txt
+++ b/lib/libc/minimal/CMakeLists.txt
@@ -22,6 +22,8 @@
source/stdout/sprintf.c
source/stdout/fprintf.c
source/time/gmtime.c
+ source/math/sqrtf.c
+ source/math/sqrt.c
)
zephyr_library_sources_ifdef(CONFIG_POSIX_CLOCK source/time/time.c)
diff --git a/lib/libc/minimal/include/math.h b/lib/libc/minimal/include/math.h
index 321d866..92bf9f4 100644
--- a/lib/libc/minimal/include/math.h
+++ b/lib/libc/minimal/include/math.h
@@ -51,6 +51,9 @@
#define M_SQRT2 1.41421356237309504880
#define M_SQRT1_2 0.70710678118654752440
+float sqrtf(float square);
+double sqrt(double square);
+
#ifdef __cplusplus
}
#endif
diff --git a/lib/libc/minimal/source/math/sqrt.c b/lib/libc/minimal/source/math/sqrt.c
new file mode 100644
index 0000000..4ed372a
--- /dev/null
+++ b/lib/libc/minimal/source/math/sqrt.c
@@ -0,0 +1,23 @@
+/*
+ * Copyright (c) 2019 Vestas Wind Systems A/S
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <math.h>
+
+double sqrt(double value)
+{
+ double sqrt = value / 3;
+ int i;
+
+ if (value <= 0) {
+ return 0;
+ }
+
+ for (i = 0; i < 6; i++) {
+ sqrt = (sqrt + value / sqrt) / 2;
+ }
+
+ return sqrt;
+}
diff --git a/lib/libc/minimal/source/math/sqrtf.c b/lib/libc/minimal/source/math/sqrtf.c
new file mode 100644
index 0000000..9e39a8d
--- /dev/null
+++ b/lib/libc/minimal/source/math/sqrtf.c
@@ -0,0 +1,29 @@
+/*
+ * Copyright (c) 2018 Vikrant More
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <math.h>
+
+#define MINDIFF 2.25e-308
+
+float sqrtf(float square)
+{
+ float root, last, diff;
+
+ root = square / 3.0;
+ diff = 1;
+
+ if (square <= 0) {
+ return 0;
+ }
+
+ do {
+ last = root;
+ root = (root + square / root) / 2.0;
+ diff = root - last;
+ } while (diff > MINDIFF || diff < -MINDIFF);
+
+ return root;
+}
diff --git a/samples/boards/nrf/mesh/onoff_level_lighting_vnd_app/src/mesh/state_binding.c b/samples/boards/nrf/mesh/onoff_level_lighting_vnd_app/src/mesh/state_binding.c
index 83a913e..c923304 100644
--- a/samples/boards/nrf/mesh/onoff_level_lighting_vnd_app/src/mesh/state_binding.c
+++ b/samples/boards/nrf/mesh/onoff_level_lighting_vnd_app/src/mesh/state_binding.c
@@ -5,6 +5,7 @@
* SPDX-License-Identifier: Apache-2.0
*/
+#include <math.h>
#include <zephyr/drivers/gpio.h>
#include "ble_mesh.h"
@@ -13,28 +14,6 @@
#include "storage.h"
#include "transition.h"
-#define MINDIFF 2.25e-308
-
-static float sqrt(float square)
-{
- float root, last, diff;
-
- root = square / 3.0;
- diff = 1;
-
- if (square <= 0) {
- return 0;
- }
-
- do {
- last = root;
- root = (root + square / root) / 2.0;
- diff = root - last;
- } while (diff > MINDIFF || diff < -MINDIFF);
-
- return root;
-}
-
static int32_t ceiling(float num)
{
int32_t inum;
@@ -58,7 +37,7 @@
static uint16_t linear_to_actual(uint16_t val)
{
- return (uint16_t) (UINT16_MAX * sqrt(((float) val / UINT16_MAX)));
+ return (uint16_t) (UINT16_MAX * sqrtf(((float) val / UINT16_MAX)));
}
uint16_t constrain_lightness(uint16_t light)
diff --git a/samples/shields/lmp90100_evb/rtd/src/main.c b/samples/shields/lmp90100_evb/rtd/src/main.c
index 8d0ce42..6094305 100644
--- a/samples/shields/lmp90100_evb/rtd/src/main.c
+++ b/samples/shields/lmp90100_evb/rtd/src/main.c
@@ -26,24 +26,6 @@
/* Bottom resistor value in ohms */
#define BOTTOM_RESISTANCE 2000
-#ifndef CONFIG_NEWLIB_LIBC
-static double sqrt(double value)
-{
- double sqrt = value / 3;
- int i;
-
- if (value <= 0) {
- return 0;
- }
-
- for (i = 0; i < 6; i++) {
- sqrt = (sqrt + value / sqrt) / 2;
- }
-
- return sqrt;
-}
-#endif /* CONFIG_NEWLIB_LIBC */
-
static double rtd_temperature(int nom, double resistance)
{
const double a0 = 3.90802E-3;
