about summary refs log tree commit diff
path: root/sysdeps/libm-i387/e_acos.S
diff options
context:
space:
mode:
Diffstat (limited to 'sysdeps/libm-i387/e_acos.S')
-rw-r--r--sysdeps/libm-i387/e_acos.S20
1 files changed, 20 insertions, 0 deletions
diff --git a/sysdeps/libm-i387/e_acos.S b/sysdeps/libm-i387/e_acos.S
new file mode 100644
index 0000000000..6ec7785363
--- /dev/null
+++ b/sysdeps/libm-i387/e_acos.S
@@ -0,0 +1,20 @@
+/*
+ * Written by J.T. Conklin <jtc@netbsd.org>.
+ * Public domain.
+ */
+
+#include <machine/asm.h>
+
+RCSID("$NetBSD: e_acos.S,v 1.4 1995/05/08 23:44:37 jtc Exp $")
+
+/* acos = atan (sqrt(1 - x^2) / x) */
+ENTRY(__ieee754_acos)
+	fldl	4(%esp)			/* x */
+	fst	%st(1)
+	fmul	%st(0)			/* x^2 */
+	fld1				
+	fsubp				/* 1 - x^2 */
+	fsqrt				/* sqrt (1 - x^2) */
+	fxch	%st(1)
+	fpatan
+	ret