From bc33e617040166e971ec1e6822ac1cc417eb6c9c Mon Sep 17 00:00:00 2001
From: Rich Felker <dalias@aerifal.cx>
Date: Mon, 19 Mar 2012 04:56:07 -0400
Subject: [PATCH] asm for inverse trig functions

unlike trig functions, these are easy to do in asm because they do not
involve (arbitrary-precision) argument reduction. fpatan automatically
takes care of domain issues, and in asin and acos, fsqrt takes care of
them for us.
---
 src/math/i386/acos.s   | 24 ++++++++++++++++++++++++
 src/math/i386/acosf.s  |  1 +
 src/math/i386/acosl.s  |  1 +
 src/math/i386/asin.s   | 23 +++++++++++++++++++++++
 src/math/i386/asinf.s  |  1 +
 src/math/i386/asinl.s  |  1 +
 src/math/i386/atan.s   |  7 +++++++
 src/math/i386/atan2.s  |  7 +++++++
 src/math/i386/atan2f.s |  7 +++++++
 src/math/i386/atan2l.s |  7 +++++++
 src/math/i386/atanf.s  |  7 +++++++
 src/math/i386/atanl.s  |  7 +++++++
 12 files changed, 93 insertions(+)
 create mode 100644 src/math/i386/acos.s
 create mode 100644 src/math/i386/acosf.s
 create mode 100644 src/math/i386/acosl.s
 create mode 100644 src/math/i386/asin.s
 create mode 100644 src/math/i386/asinf.s
 create mode 100644 src/math/i386/asinl.s
 create mode 100644 src/math/i386/atan.s
 create mode 100644 src/math/i386/atan2.s
 create mode 100644 src/math/i386/atan2f.s
 create mode 100644 src/math/i386/atan2l.s
 create mode 100644 src/math/i386/atanf.s
 create mode 100644 src/math/i386/atanl.s

diff --git a/src/math/i386/acos.s b/src/math/i386/acos.s
new file mode 100644
index 00000000..6f9ef7f0
--- /dev/null
+++ b/src/math/i386/acos.s
@@ -0,0 +1,24 @@
+.global acosf
+.type acosf,@function
+acosf:
+	flds 4(%esp)
+	jmp 1f
+
+.global acosl
+.type acosl,@function
+acosl:
+	fldt 4(%esp)
+	jmp 1f
+
+.global acos
+.type acos,@function
+acos:
+	fldl 4(%esp)
+1:	fld %st(0)
+	fmul %st(0)
+	fld1
+	fsubp %st(1)
+	fsqrt
+	fxch %st(1)
+	fpatan
+	ret
diff --git a/src/math/i386/acosf.s b/src/math/i386/acosf.s
new file mode 100644
index 00000000..6c95509f
--- /dev/null
+++ b/src/math/i386/acosf.s
@@ -0,0 +1 @@
+# see acos.s
diff --git a/src/math/i386/acosl.s b/src/math/i386/acosl.s
new file mode 100644
index 00000000..6c95509f
--- /dev/null
+++ b/src/math/i386/acosl.s
@@ -0,0 +1 @@
+# see acos.s
diff --git a/src/math/i386/asin.s b/src/math/i386/asin.s
new file mode 100644
index 00000000..cab7bfc8
--- /dev/null
+++ b/src/math/i386/asin.s
@@ -0,0 +1,23 @@
+.global asinf
+.type asinf,@function
+asinf:
+	flds 4(%esp)
+	jmp 1f
+
+.global asinl
+.type asinl,@function
+asinl:
+	fldt 4(%esp)
+	jmp 1f
+
+.global asin
+.type asin,@function
+asin:
+	fldl 4(%esp)
+1:	fld %st(0)
+	fmul %st(0)
+	fld1
+	fsubp %st(1)
+	fsqrt
+	fpatan
+	ret
diff --git a/src/math/i386/asinf.s b/src/math/i386/asinf.s
new file mode 100644
index 00000000..e07bf599
--- /dev/null
+++ b/src/math/i386/asinf.s
@@ -0,0 +1 @@
+# see asin.s
diff --git a/src/math/i386/asinl.s b/src/math/i386/asinl.s
new file mode 100644
index 00000000..e07bf599
--- /dev/null
+++ b/src/math/i386/asinl.s
@@ -0,0 +1 @@
+# see asin.s
diff --git a/src/math/i386/atan.s b/src/math/i386/atan.s
new file mode 100644
index 00000000..7e28b395
--- /dev/null
+++ b/src/math/i386/atan.s
@@ -0,0 +1,7 @@
+.global atan
+.type atan,@function
+atan:
+	fldl 4(%esp)
+	fld1
+	fpatan
+	ret
diff --git a/src/math/i386/atan2.s b/src/math/i386/atan2.s
new file mode 100644
index 00000000..5c795aff
--- /dev/null
+++ b/src/math/i386/atan2.s
@@ -0,0 +1,7 @@
+.global atan2
+.type atan2,@function
+atan2:
+	fldl 4(%esp)
+	fldl 12(%esp)
+	fpatan
+	ret
diff --git a/src/math/i386/atan2f.s b/src/math/i386/atan2f.s
new file mode 100644
index 00000000..08627e63
--- /dev/null
+++ b/src/math/i386/atan2f.s
@@ -0,0 +1,7 @@
+.global atan2f
+.type atan2f,@function
+atan2f:
+	flds 4(%esp)
+	flds 8(%esp)
+	fpatan
+	ret
diff --git a/src/math/i386/atan2l.s b/src/math/i386/atan2l.s
new file mode 100644
index 00000000..adf6e10a
--- /dev/null
+++ b/src/math/i386/atan2l.s
@@ -0,0 +1,7 @@
+.global atan2l
+.type atan2l,@function
+atan2l:
+	fldt 4(%esp)
+	fldt 16(%esp)
+	fpatan
+	ret
diff --git a/src/math/i386/atanf.s b/src/math/i386/atanf.s
new file mode 100644
index 00000000..3cd40233
--- /dev/null
+++ b/src/math/i386/atanf.s
@@ -0,0 +1,7 @@
+.global atanf
+.type atanf,@function
+atanf:
+	flds 4(%esp)
+	fld1
+	fpatan
+	ret
diff --git a/src/math/i386/atanl.s b/src/math/i386/atanl.s
new file mode 100644
index 00000000..c508bc46
--- /dev/null
+++ b/src/math/i386/atanl.s
@@ -0,0 +1,7 @@
+.global atanl
+.type atanl,@function
+atanl:
+	fldt 4(%esp)
+	fld1
+	fpatan
+	ret
-- 
2.25.1