Piotr Caban : msvcrt: Import log2f implementation from musl.
Alexandre Julliard
julliard at winehq.org
Fri Jun 4 14:32:29 CDT 2021
Module: wine
Branch: master
Commit: 301bde60d3335ec78aa4bb4622dc14c5ea1eec92
URL: https://source.winehq.org/git/wine.git/?a=commit;h=301bde60d3335ec78aa4bb4622dc14c5ea1eec92
Author: Piotr Caban <piotr at codeweavers.com>
Date: Fri Jun 4 18:25:41 2021 +0200
msvcrt: Import log2f implementation from musl.
Signed-off-by: Piotr Caban <piotr at codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard at winehq.org>
---
configure | 1 -
configure.ac | 1 -
dlls/msvcrt/math.c | 83 +++++++++++++++++++++++++++++++++++++++++++++++++--
dlls/msvcrt/unixlib.c | 13 --------
dlls/msvcrt/unixlib.h | 1 -
include/config.h.in | 3 --
6 files changed, 80 insertions(+), 22 deletions(-)
diff --git a/configure b/configure
index e73670fc110..08a28968945 100755
--- a/configure
+++ b/configure
@@ -19623,7 +19623,6 @@ for ac_func in \
lgamma \
lgammaf \
log2 \
- log2f \
tgamma \
tgammaf
diff --git a/configure.ac b/configure.ac
index b13c2ad3182..71c95cbdd90 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2662,7 +2662,6 @@ AC_CHECK_FUNCS(\
lgamma \
lgammaf \
log2 \
- log2f \
tgamma \
tgammaf
)
diff --git a/dlls/msvcrt/math.c b/dlls/msvcrt/math.c
index 0176b6544c0..88a5ecd240f 100644
--- a/dlls/msvcrt/math.c
+++ b/dlls/msvcrt/math.c
@@ -7176,12 +7176,89 @@ double CDECL log2(double x)
/*********************************************************************
* log2f (MSVCR120.@)
+ *
+ * Copied from musl: src/math/log2f.c
*/
float CDECL log2f(float x)
{
- if (x < 0) *_errno() = EDOM;
- else if (x == 0) *_errno() = ERANGE;
- return unix_funcs->log2f( x );
+ static const double A[] = {
+ -0x1.712b6f70a7e4dp-2,
+ 0x1.ecabf496832ep-2,
+ -0x1.715479ffae3dep-1,
+ 0x1.715475f35c8b8p0
+ };
+ static const struct {
+ double invc, logc;
+ } T[] = {
+ { 0x1.661ec79f8f3bep+0, -0x1.efec65b963019p-2 },
+ { 0x1.571ed4aaf883dp+0, -0x1.b0b6832d4fca4p-2 },
+ { 0x1.49539f0f010bp+0, -0x1.7418b0a1fb77bp-2 },
+ { 0x1.3c995b0b80385p+0, -0x1.39de91a6dcf7bp-2 },
+ { 0x1.30d190c8864a5p+0, -0x1.01d9bf3f2b631p-2 },
+ { 0x1.25e227b0b8eap+0, -0x1.97c1d1b3b7afp-3 },
+ { 0x1.1bb4a4a1a343fp+0, -0x1.2f9e393af3c9fp-3 },
+ { 0x1.12358f08ae5bap+0, -0x1.960cbbf788d5cp-4 },
+ { 0x1.0953f419900a7p+0, -0x1.a6f9db6475fcep-5 },
+ { 0x1p+0, 0x0p+0 },
+ { 0x1.e608cfd9a47acp-1, 0x1.338ca9f24f53dp-4 },
+ { 0x1.ca4b31f026aap-1, 0x1.476a9543891bap-3 },
+ { 0x1.b2036576afce6p-1, 0x1.e840b4ac4e4d2p-3 },
+ { 0x1.9c2d163a1aa2dp-1, 0x1.40645f0c6651cp-2 },
+ { 0x1.886e6037841edp-1, 0x1.88e9c2c1b9ff8p-2 },
+ { 0x1.767dcf5534862p-1, 0x1.ce0a44eb17bccp-2 }
+ };
+
+ double z, r, r2, p, y, y0, invc, logc;
+ UINT32 ix, iz, top, tmp;
+ int k, i;
+
+ ix = *(UINT32*)&x;
+ /* Fix sign of zero with downward rounding when x==1. */
+ if (ix == 0x3f800000)
+ return 0;
+ if (ix - 0x00800000 >= 0x7f800000 - 0x00800000) {
+ /* x < 0x1p-126 or inf or nan. */
+ if (ix * 2 == 0) {
+ *_errno() = ERANGE;
+ return -1.0f / x;
+ }
+ if (ix == 0x7f800000) /* log2(inf) == inf. */
+ return x;
+ if (ix * 2 > 0xff000000)
+ return x;
+ if (ix & 0x80000000) {
+ *_errno() = EDOM;
+ return (x - x) / (x - x);
+ }
+ /* x is subnormal, normalize it. */
+ x *= 0x1p23f;
+ ix = *(UINT32*)&x;
+ ix -= 23 << 23;
+ }
+
+ /* x = 2^k z; where z is in range [OFF,2*OFF] and exact.
+ The range is split into N subintervals.
+ The ith subinterval contains z and c is near its center. */
+ tmp = ix - 0x3f330000;
+ i = (tmp >> (23 - 4)) % (1 << 4);
+ top = tmp & 0xff800000;
+ iz = ix - top;
+ k = (INT32)tmp >> 23; /* arithmetic shift */
+ invc = T[i].invc;
+ logc = T[i].logc;
+ z = *(float*)&iz;
+
+ /* log2(x) = log1p(z/c-1)/ln2 + log2(c) + k */
+ r = z * invc - 1;
+ y0 = logc + (double)k;
+
+ /* Pipelined polynomial evaluation to approximate log1p(r)/ln2. */
+ r2 = r * r;
+ y = A[1] * r + A[2];
+ y = A[0] * r2 + y;
+ p = A[3] * r + y0;
+ y = y * r2 + p;
+ return y;
}
/*********************************************************************
diff --git a/dlls/msvcrt/unixlib.c b/dlls/msvcrt/unixlib.c
index 4311de356df..b23afaf7123 100644
--- a/dlls/msvcrt/unixlib.c
+++ b/dlls/msvcrt/unixlib.c
@@ -132,18 +132,6 @@ static double CDECL unix_log2(double x)
#endif
}
-/*********************************************************************
- * log2f
- */
-static float CDECL unix_log2f(float x)
-{
-#ifdef HAVE_LOG2F
- return log2f(x);
-#else
- return unix_log2(x);
-#endif
-}
-
/*********************************************************************
* pow
*/
@@ -196,7 +184,6 @@ static const struct unix_funcs funcs =
unix_lgamma,
unix_lgammaf,
unix_log2,
- unix_log2f,
unix_pow,
unix_powf,
unix_tgamma,
diff --git a/dlls/msvcrt/unixlib.h b/dlls/msvcrt/unixlib.h
index d907d68dd7d..85f74e5fb12 100644
--- a/dlls/msvcrt/unixlib.h
+++ b/dlls/msvcrt/unixlib.h
@@ -31,7 +31,6 @@ struct unix_funcs
double (CDECL *lgamma)(double x);
float (CDECL *lgammaf)(float x);
double (CDECL *log2)(double x);
- float (CDECL *log2f)(float x);
double (CDECL *pow)(double x, double y);
float (CDECL *powf)(float x, float y);
double (CDECL *tgamma)(double x);
diff --git a/include/config.h.in b/include/config.h.in
index 1b308f3d34c..d0e3ccb60fe 100644
--- a/include/config.h.in
+++ b/include/config.h.in
@@ -411,9 +411,6 @@
/* Define to 1 if you have the `log2' function. */
#undef HAVE_LOG2
-/* Define to 1 if you have the `log2f' function. */
-#undef HAVE_LOG2F
-
/* Define to 1 if you have the `lstat' function. */
#undef HAVE_LSTAT
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