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[tyndur-devel] [PATCH] libm: Rundungsfunktionen
+ libm: floor, ceil, round, trunc, nearbyint, fesetround, fegetround
Signed-off-by: Kevin Wolf <kevin@xxxxxxxxxx>
---
src/modules/include/math.h | 25 ++++
src/modules/lib/stdlibc/math/round.c | 212 ++++++++++++++++++++++++++++++++++
2 files changed, 237 insertions(+), 0 deletions(-)
create mode 100644 src/modules/lib/stdlibc/math/round.c
diff --git a/src/modules/include/math.h b/src/modules/include/math.h
index 49083ab..138fff3 100644
--- a/src/modules/include/math.h
+++ b/src/modules/include/math.h
@@ -49,6 +49,12 @@
#define M_SQRT2 1.41421356237309504880
#define M_SQRT1_2 0.70710678118654752440
+enum {
+ FE_TONEAREST,
+ FE_UPWARD,
+ FE_DOWNWARD,
+ FE_TOWARDZERO,
+};
double tan(double);
@@ -94,5 +100,24 @@ double acos(double);
float acosf(float);
long double acosl(long double);
+
+double floor(double x);
+float floorf(float x);
+long double floorl(long double x);
+double ceil(double x);
+float ceilf(float x);
+long double ceill(long double x);
+double trunc(double x);
+float truncf(float x);
+long double truncl(long double x);
+double round(double x);
+float roundf(float x);
+long double roundl(long double x);
+int fegetround(void);
+int fesetround(int rounding_mode);
+double nearbyint(double x);
+float nearbyintf(float x);
+long double nearbyintl(long double x);
+
#endif
diff --git a/src/modules/lib/stdlibc/math/round.c b/src/modules/lib/stdlibc/math/round.c
new file mode 100644
index 0000000..b4fd618
--- /dev/null
+++ b/src/modules/lib/stdlibc/math/round.c
@@ -0,0 +1,212 @@
+/*
+ * Copyright (c) 2009 The tyndur Project. All rights reserved.
+ *
+ * This code is derived from software contributed to the tyndur Project
+ * by Kevin Wolf.
+ *
+ * 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 COPYRIGHT HOLDERS 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 COPYRIGHT HOLDERS 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.
+ */
+
+#include <math.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+#define ROUND_NEAR "$0x000"
+#define ROUND_DOWN "$0x400"
+#define ROUND_UP "$0x800"
+#define ROUND_TRUNC "$0xc00"
+
+static int rounding_mode = FE_TONEAREST;
+
+/*
+ * Achtung:
+ *
+ * Die folgenden Funktionen basieren auf der Annahme, dass das RC-Feld im FPU
+ * Control Word normalerweise immer auf 0 gesetzt ist, also der neue Wert durch
+ * ein einfaches or eingetragen werden kann.
+ */
+
+long double floorl(long double x)
+{
+ long double res;
+ uint16_t control_word;
+
+ asm(
+ // Rundungsmodus setzen
+ "fnstcw %2;"
+ "mov %2, %%eax;"
+ "orl " ROUND_DOWN ", %2;"
+ "fldcw %2;"
+
+ // Zahl auf dem Stack runden
+ "frndint;"
+
+ // Wieder den Standardrundungsmodus setzen
+ "mov %%eax, %2;"
+ "fldcw %2;"
+ : "=t" (res) : "0" (x), "m" (control_word) : "eax");
+
+ return res;
+}
+
+double floor(double x)
+{
+ return floorl(x);
+}
+
+float floorf(float x)
+{
+ return floorl(x);
+}
+
+
+long double ceill(long double x)
+{
+ long double res;
+ uint16_t control_word;
+
+ asm(
+ // Rundungsmodus setzen
+ "fnstcw %2;"
+ "mov %2, %%eax;"
+ "orl " ROUND_UP ", %2;"
+ "fldcw %2;"
+
+ // Zahl auf dem Stack runden
+ "frndint;"
+
+ // Wieder den Standardrundungsmodus setzen
+ "mov %%eax, %2;"
+ "fldcw %2;"
+ : "=t" (res) : "0" (x), "m" (control_word) : "eax");
+
+ return res;
+}
+
+double ceil(double x)
+{
+ return ceill(x);
+}
+
+float ceilf(float x)
+{
+ return ceill(x);
+}
+
+long double truncl(long double x)
+{
+ long double res;
+ uint16_t control_word;
+
+ asm(
+ // Rundungsmodus setzen
+ "fnstcw %2;"
+ "mov %2, %%eax;"
+ "orl " ROUND_TRUNC ", %2;"
+ "fldcw %2;"
+
+ // Zahl auf dem Stack runden
+ "frndint;"
+
+ // Wieder den Standardrundungsmodus setzen
+ "mov %%eax, %2;"
+ "fldcw %2;"
+ : "=t" (res) : "0" (x), "m" (control_word) : "eax");
+
+ return res;
+}
+
+double trunc(double x)
+{
+ return truncl(x);
+}
+
+float truncf(float x)
+{
+ return truncl(x);
+}
+
+long double roundl(long double x)
+{
+ long double res;
+
+ asm("frndint" : "=t" (res) : "0" (x));
+
+ return res;
+}
+
+double round(double x)
+{
+ return roundl(x);
+}
+
+float roundf(float x)
+{
+ return roundl(x);
+}
+
+long double nearbyintl(long double x)
+{
+ switch (rounding_mode) {
+ case FE_TONEAREST:
+ return roundl(x);
+ case FE_TOWARDZERO:
+ return truncl(x);
+ case FE_DOWNWARD:
+ return floorl(x);
+ case FE_UPWARD:
+ return ceill(x);
+ }
+
+ abort();
+ return x;
+}
+
+double nearbyint(double x)
+{
+ return nearbyintl(x);
+}
+
+float nearbyintf(float x)
+{
+ return nearbyintl(x);
+}
+
+int fegetround(void)
+{
+ return rounding_mode;
+}
+
+int fesetround(int mode)
+{
+ switch(mode) {
+ case FE_TONEAREST:
+ case FE_TOWARDZERO:
+ case FE_DOWNWARD:
+ case FE_UPWARD:
+ rounding_mode = mode;
+ return 0;
+
+ default:
+ return -1;
+ }
+}
--
1.6.0.2