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-rw-r--r--system/musl/complex-math.patch59
1 files changed, 59 insertions, 0 deletions
diff --git a/system/musl/complex-math.patch b/system/musl/complex-math.patch
new file mode 100644
index 000000000..fff4b59c1
--- /dev/null
+++ b/system/musl/complex-math.patch
@@ -0,0 +1,59 @@
+From ae2a01da2e388535da243b3d974aef74a3c06ae0 Mon Sep 17 00:00:00 2001
+From: Rich Felker <dalias@aerifal.cx>
+Date: Mon, 9 Apr 2018 12:33:17 -0400
+Subject: fix wrong result in casin and many related complex functions
+
+the factor of -i noted in the comment at the top of casin.c was
+omitted from the actual code, yielding a result rotated 90 degrees and
+propagating into errors in other functions defined in terms of casin.
+
+implement multiplication by -i as a rotation of the real and imaginary
+parts of the result, rather than by actual multiplication, since the
+latter cannot be optimized without knowledge that the operand is
+finite. here, the rotation is the actual intent, anyway.
+---
+ src/complex/casin.c | 3 ++-
+ src/complex/casinf.c | 3 ++-
+ src/complex/casinl.c | 3 ++-
+ 3 files changed, 6 insertions(+), 3 deletions(-)
+
+diff --git a/src/complex/casin.c b/src/complex/casin.c
+index dfdda98..01ed618 100644
+--- a/src/complex/casin.c
++++ b/src/complex/casin.c
+@@ -12,5 +12,6 @@ double complex casin(double complex z)
+ x = creal(z);
+ y = cimag(z);
+ w = CMPLX(1.0 - (x - y)*(x + y), -2.0*x*y);
+- return clog(CMPLX(-y, x) + csqrt(w));
++ double complex r = clog(CMPLX(-y, x) + csqrt(w));
++ return CMPLX(cimag(r), -creal(r));
+ }
+diff --git a/src/complex/casinf.c b/src/complex/casinf.c
+index 93f0e33..4fcb76f 100644
+--- a/src/complex/casinf.c
++++ b/src/complex/casinf.c
+@@ -10,5 +10,6 @@ float complex casinf(float complex z)
+ x = crealf(z);
+ y = cimagf(z);
+ w = CMPLXF(1.0 - (x - y)*(x + y), -2.0*x*y);
+- return clogf(CMPLXF(-y, x) + csqrtf(w));
++ float complex r = clogf(CMPLXF(-y, x) + csqrtf(w));
++ return CMPLXF(cimagf(r), -crealf(r));
+ }
+diff --git a/src/complex/casinl.c b/src/complex/casinl.c
+index 0916c60..3b7ceba 100644
+--- a/src/complex/casinl.c
++++ b/src/complex/casinl.c
+@@ -15,6 +15,7 @@ long double complex casinl(long double complex z)
+ x = creall(z);
+ y = cimagl(z);
+ w = CMPLXL(1.0 - (x - y)*(x + y), -2.0*x*y);
+- return clogl(CMPLXL(-y, x) + csqrtl(w));
++ long double complex r = clogl(CMPLXL(-y, x) + csqrtl(w));
++ return CMPLXL(cimagl(r), -creall(r));
+ }
+ #endif
+--
+cgit v0.11.2
+