From aa2d23e57c9c95f0ffeb80cb035e5a5be52d8ef0 Mon Sep 17 00:00:00 2001
From: Michael Morrell <mmorrell@tachyum.com>
Date: Mon, 14 Oct 2019 09:07:31 -0400
Subject: fix cacosh results for arguments with negative imaginary part

---
 src/complex/cacosh.c  | 5 ++++-
 src/complex/cacoshf.c | 5 ++++-
 src/complex/cacoshl.c | 5 ++++-
 3 files changed, 12 insertions(+), 3 deletions(-)

(limited to 'src')

diff --git a/src/complex/cacosh.c b/src/complex/cacosh.c
index 8e42f1ae..76127f75 100644
--- a/src/complex/cacosh.c
+++ b/src/complex/cacosh.c
@@ -4,6 +4,9 @@
 
 double complex cacosh(double complex z)
 {
+	int zineg = signbit(cimag(z));
+
 	z = cacos(z);
-	return CMPLX(-cimag(z), creal(z));
+	if (zineg) return CMPLX(cimag(z), -creal(z));
+	else       return CMPLX(-cimag(z), creal(z));
 }
diff --git a/src/complex/cacoshf.c b/src/complex/cacoshf.c
index d7e6b545..8bd80581 100644
--- a/src/complex/cacoshf.c
+++ b/src/complex/cacoshf.c
@@ -2,6 +2,9 @@
 
 float complex cacoshf(float complex z)
 {
+	int zineg = signbit(cimagf(z));
+
 	z = cacosf(z);
-	return CMPLXF(-cimagf(z), crealf(z));
+	if (zineg) return CMPLXF(cimagf(z), -crealf(z));
+	else       return CMPLXF(-cimagf(z), crealf(z));
 }
diff --git a/src/complex/cacoshl.c b/src/complex/cacoshl.c
index d3eaee20..3a284be9 100644
--- a/src/complex/cacoshl.c
+++ b/src/complex/cacoshl.c
@@ -8,7 +8,10 @@ long double complex cacoshl(long double complex z)
 #else
 long double complex cacoshl(long double complex z)
 {
+	int zineg = signbit(cimagl(z));
+
 	z = cacosl(z);
-	return CMPLXL(-cimagl(z), creall(z));
+	if (zineg) return CMPLXL(cimagl(z), -creall(z));
+	else       return CMPLXL(-cimagl(z), creall(z));
 }
 #endif
-- 
cgit v1.2.3-70-g09d2