newlib: strtold: Import strtorQ for 128-bit long double supportHEADmastermain

The implementation of strtorQ is imported from FreeBSD's gdtoa library (By David
M. Gay) with some adaptations to fit with newlib.

`strtorQ.c` enables `strtold` to perform correct parsing on targets where long
double uses the IEEE754 binary128 format (113-bit mantissa), such as AArch64.
Without this patch, strtold would wrongly fallback to `strtorx` which will
parse into a 80-bit long double and give invalid result.

* libc/stdlib/strtorQ.c: New file, adapted from FreeBSD gdtoa.
* libc/stdlib/strtold.c (_strtold_impl): New helper selecting strtorx
  for 80-bit and strtorQ for 128-bit long double.
  (_strtold_r, strtold_l, strtold): Use _strtold_impl.
* libc/stdlib/mprec.h (_strtorQ_l): Declare.
* libc/stdlib/Makefile.inc (libc_a_SOURCES): Add strtorQ.c.
* newlib/Makefile.in: Regenerate with automake

Signed-off-by: Zakaria Fadli <fadli@adacore.com>

1 files changed, 129 insertions, 0 deletions

diff --git a/newlib/libc/stdlib/strtorQ.c b/newlib/libc/stdlib/strtorQ.c
new file mode 100644
index 0000000..e9e0b9f
--- /dev/null
+++ b/newlib/libc/stdlib/strtorQ.c
@@ -0,0 +1,129 @@
+/****************************************************************
+
+The author of this software is David M. Gay.
+
+Copyright (C) 1998, 2000 by Lucent Technologies
+All Rights Reserved
+
+Permission to use, copy, modify, and distribute this software and
+its documentation for any purpose and without fee is hereby
+granted, provided that the above copyright notice appear in all
+copies and that both that the copyright notice and this
+permission notice and warranty disclaimer appear in supporting
+documentation, and that the name of Lucent or any of its entities
+not be used in advertising or publicity pertaining to
+distribution of the software without specific, written prior
+permission.
+
+LUCENT DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
+INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS.
+IN NO EVENT SHALL LUCENT OR ANY OF ITS ENTITIES BE LIABLE FOR ANY
+SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER
+IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
+ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
+THIS SOFTWARE.
+
+****************************************************************/
+
+/* Please send bug reports to David M. Gay (dmg at acm dot org,
+ * with " at " changed at "@" and " dot " changed to ".").	*/
+
+#include <_ansi.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+#include "mprec.h"
+#include "gdtoa.h"
+
+#if defined (_HAVE_LONG_DOUBLE) && !defined (_LDBL_EQ_DBL)
+
+/* one or the other of IEEE_MC68k or IEEE_8087 should be #defined */
+
+#ifdef IEEE_MC68k
+#define _0 0
+#define _1 1
+#define _2 2
+#define _3 3
+#endif
+#ifdef IEEE_8087
+#define _0 3
+#define _1 2
+#define _2 1
+#define _3 0
+#endif
+
+ void
+#ifdef KR_headers
+ULtoQ(L, bits, exp, k) ULong *L; ULong *bits; Long exp; int k;
+#else
+ULtoQ(ULong *L, ULong *bits, Long exp, int k)
+#endif
+{
+	switch(k & STRTOG_Retmask) {
+	  case STRTOG_NoNumber:
+	  case STRTOG_Zero:
+		L[0] = L[1] = L[2] = L[3] = 0;
+		break;
+
+	  case STRTOG_Normal:
+		L[_3] = bits[0];
+		L[_2] = bits[1];
+		L[_1] = bits[2];
+		L[_0] = (bits[3] & ~0x10000) | ((exp + 0x3fff + 112) << 16);
+		break;
+
+	  case STRTOG_NaNbits:
+		L[_3] = bits[0];
+		L[_2] = bits[1];
+		L[_1] = bits[2];
+		L[_0] = (bits[3] & ~0x10000)
+		    | (((exp + 0x3fff + 112) << 16) | (1 << 15));
+		break;
+
+	  case STRTOG_Denormal:
+		L[_3] = bits[0];
+		L[_2] = bits[1];
+		L[_1] = bits[2];
+		L[_0] = bits[3];
+		break;
+
+	  case STRTOG_Infinite:
+		L[_0] = 0x7fff0000;
+		L[_1] = L[_2] = L[_3] = 0;
+		break;
+
+	  case STRTOG_NaN:
+		*((long double*)L) = __builtin_nanl ("");
+	  }
+	if (k & STRTOG_Neg)
+		L[_0] |= 0x80000000L;
+	}
+
+ int
+#ifdef KR_headers
+_strtorQ_l(p, s, sp, rounding, L, locale) struct _reent *p; CONST char *s;
+char **sp; int rounding; void *L; locale_t locale;
+#else
+_strtorQ_l(struct _reent *p, CONST char *s, char **sp,
+           int rounding, void *L, locale_t locale)
+#endif
+{
+	static FPI fpi0 = { 113, 1-16383-113+1, 32766-16383-113+1, 1, SI };
+	FPI *fpi, fpi1;
+	ULong bits[4];
+	Long exp;
+	int k;
+
+	fpi = &fpi0;
+	if (rounding != FPI_Round_near) {
+		fpi1 = fpi0;
+		fpi1.rounding = rounding;
+		fpi = &fpi1;
+		}
+	k = _strtodg_l(p, s, sp, fpi, &exp, bits, locale);
+	ULtoQ((ULong*)L, bits, exp, k);
+	return k;
+	}
+
+#endif /* _HAVE_LONG_DOUBLE && !_LDBL_EQ_DBL */