Module Name: src
Committed By: isaki
Date: Fri Apr 19 13:57:53 UTC 2013
Modified Files:
src/sys/arch/m68k/fpe: fpu_trig.c
Log Message:
Implement inverse trigonometric functions (i.e., FACOS, FASIN, FATAN
instructions).
o arccos is calculated using arcsin.
o arcsin is calculated using arctan.
o arctan is calculated by the CORDIC.
To generate a diff of this commit:
cvs rdiff -u -r1.11 -r1.12 src/sys/arch/m68k/fpe/fpu_trig.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/arch/m68k/fpe/fpu_trig.c
diff -u src/sys/arch/m68k/fpe/fpu_trig.c:1.11 src/sys/arch/m68k/fpe/fpu_trig.c:1.12
--- src/sys/arch/m68k/fpe/fpu_trig.c:1.11 Fri Apr 19 13:31:11 2013
+++ src/sys/arch/m68k/fpe/fpu_trig.c Fri Apr 19 13:57:52 2013
@@ -1,4 +1,4 @@
-/* $NetBSD: fpu_trig.c,v 1.11 2013/04/19 13:31:11 isaki Exp $ */
+/* $NetBSD: fpu_trig.c,v 1.12 2013/04/19 13:57:52 isaki Exp $ */
/*
* Copyright (c) 1995 Ken Nakata
@@ -57,28 +57,120 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: fpu_trig.c,v 1.11 2013/04/19 13:31:11 isaki Exp $");
+__KERNEL_RCSID(0, "$NetBSD: fpu_trig.c,v 1.12 2013/04/19 13:57:52 isaki Exp $");
#include "fpu_emulate.h"
+/*
+ * arccos(x) = pi/2 - arcsin(x)
+ */
struct fpn *
fpu_acos(struct fpemu *fe)
{
- /* stub */
- return &fe->fe_f2;
+ struct fpn *r;
+
+ if (ISNAN(&fe->fe_f2))
+ return &fe->fe_f2;
+ if (ISINF(&fe->fe_f2))
+ return fpu_newnan(fe);
+
+ r = fpu_asin(fe);
+ CPYFPN(&fe->fe_f2, r);
+
+ /* pi/2 - asin(x) */
+ fpu_const(&fe->fe_f1, FPU_CONST_PI);
+ fe->fe_f1.fp_exp--;
+ fe->fe_f2.fp_sign = !fe->fe_f2.fp_sign;
+ r = fpu_add(fe);
+
+ return r;
}
+/*
+ * x
+ * arcsin(x) = arctan(---------------)
+ * sqrt(1 - x^2)
+ */
struct fpn *
fpu_asin(struct fpemu *fe)
{
- /* stub */
- return &fe->fe_f2;
+ struct fpn x;
+ struct fpn *r;
+
+ if (ISNAN(&fe->fe_f2))
+ return &fe->fe_f2;
+ if (ISZERO(&fe->fe_f2))
+ return &fe->fe_f2;
+
+ if (ISINF(&fe->fe_f2))
+ return fpu_newnan(fe);
+
+ CPYFPN(&x, &fe->fe_f2);
+
+ /* x^2 */
+ CPYFPN(&fe->fe_f1, &fe->fe_f2);
+ r = fpu_mul(fe);
+
+ /* 1 - x^2 */
+ CPYFPN(&fe->fe_f2, r);
+ fe->fe_f2.fp_sign = 1;
+ fpu_const(&fe->fe_f1, FPU_CONST_1);
+ r = fpu_add(fe);
+
+ /* sqrt(1-x^2) */
+ CPYFPN(&fe->fe_f2, r);
+ r = fpu_sqrt(fe);
+
+ /* x/sqrt */
+ CPYFPN(&fe->fe_f2, r);
+ CPYFPN(&fe->fe_f1, &x);
+ r = fpu_div(fe);
+
+ /* arctan */
+ CPYFPN(&fe->fe_f2, r);
+ return fpu_atan(fe);
}
+/*
+ * arctan(x):
+ *
+ * if (x < 0) {
+ * x = abs(x);
+ * sign = 1;
+ * }
+ * y = arctan(x);
+ * if (sign) {
+ * y = -y;
+ * }
+ */
struct fpn *
fpu_atan(struct fpemu *fe)
{
- /* stub */
+ struct fpn a;
+ struct fpn x;
+ struct fpn v;
+
+ if (ISNAN(&fe->fe_f2))
+ return &fe->fe_f2;
+ if (ISZERO(&fe->fe_f2))
+ return &fe->fe_f2;
+
+ CPYFPN(&a, &fe->fe_f2);
+
+ if (ISINF(&fe->fe_f2)) {
+ /* f2 <- pi/2 */
+ fpu_const(&fe->fe_f2, FPU_CONST_PI);
+ fe->fe_f2.fp_exp--;
+
+ fe->fe_f2.fp_sign = a.fp_sign;
+ return &fe->fe_f2;
+ }
+
+ fpu_const(&x, FPU_CONST_1);
+ fpu_const(&fe->fe_f2, FPU_CONST_0);
+ CPYFPN(&v, &fe->fe_f2);
+ fpu_cordit1(fe, &x, &a, &fe->fe_f2, &v);
+
return &fe->fe_f2;
}
