Port a lot more code to AARCH64

- Introduce epoll_pwait()
- Rewrite -ftrapv and ffs() libraries in C code
- Use more FreeBSD code in math function library
- Get significantly more tests passing on qemu-aarch64
- Fix many Musl long double functions that were broken on AARCH64

third_party/gdtoa/g_Qfmt_p.c

@@ -0,0 +1,106 @@
+/*-*- mode:c;indent-tabs-mode:t;c-basic-offset:8;tab-width:8;coding:utf-8   -*-│
+│vi: set et ft=c ts=8 tw=8 fenc=utf-8                                       :vi│
+╚──────────────────────────────────────────────────────────────────────────────╝
+│                                                                              │
+│  The author of this software is David M. Gay.                                │
+│  Please send bug reports to David M. Gay <dmg@acm.org>                       │
+│                          or Justine Tunney <jtunney@gmail.com>               │
+│                                                                              │
+│  Copyright (C) 1998, 1999 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.                                                              │
+│                                                                              │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/str/str.h"
+#include "third_party/gdtoa/gdtoa.h"
+#include "third_party/gdtoa/gdtoa.internal.h"
+// clang-format off
+
+/**
+ * Converts quadruple-precision floating-point number to string.
+ */
+char*
+g_Qfmt_p(char *buf, void *V, int ndig, size_t bufsize, int nik)
+{
+	static const FPI fpi0 = { 113, 1-16383-113+1, 32766 - 16383 - 113 + 1, 1, 0, Int_max };
+	char *b, *s, *se;
+	ULong bits[4], *L, sign;
+	int decpt, ex, i, mode;
+#include "third_party/gdtoa/gdtoa_fltrnds.inc"
+	if (ndig < 0)
+		ndig = 0;
+	if (bufsize < (size_t)(ndig + 10))
+		return 0;
+	L = (ULong*)V;
+	sign = L[3] & 0x80000000L;
+	bits[3] = L[3] & 0xffff;
+	bits[2] = L[2];
+	bits[1] = L[1];
+	bits[0] = L[0];
+	b = buf;
+	if ( (ex = (L[3] & 0x7fff0000L) >> 16) !=0) {
+		if (ex == 0x7fff) {
+			/* Infinity or NaN */
+			if (nik < 0 || nik > 35)
+				nik = 0;
+			if (bits[0] | bits[1] | bits[2] | bits[3]) {
+				if (sign && nik < 18)
+					*b++ = '-';
+				b = strcpy(b, __gdtoa_NanName[nik%3]);
+				if (nik > 5 && (nik < 12
+						|| bits[0] != __gdtoa_NanDflt_Q[0]
+						|| bits[1] != __gdtoa_NanDflt_Q[1]
+						|| bits[2] != __gdtoa_NanDflt_Q[2]
+						|| (bits[2] ^ __gdtoa_NanDflt_Q[2]) & 0xffff))
+					b = __gdtoa_add_nanbits(b, bufsize - (b-buf), bits, 4);
+				}
+			else {
+				b = buf;
+				if (sign)
+					*b++ = '-';
+				b = strcpy(b, __gdtoa_InfName[nik%6]);
+				}
+			return b;
+			}
+		i = STRTOG_Normal;
+		bits[3] |= 0x10000;
+		}
+	else if (bits[0] | bits[1] | bits[2] | bits[3]) {
+		i = STRTOG_Denormal;
+		ex = 1;
+		}
+	else {
+		if (sign)
+			*b++ = '-';
+		*b++ = '0';
+		*b = 0;
+		return b;
+		}
+	ex -= 0x3fff + 112;
+	mode = 2;
+	if (ndig <= 0) {
+		if (bufsize < 48)
+			return 0;
+		mode = 0;
+		}
+	s = gdtoa(fpi, ex, bits, &i, mode, ndig, &decpt, &se);
+	return __gdtoa_g__fmt(buf, s, se, decpt, sign, bufsize);
+}

third_party/gdtoa/gdtoa.internal.h

@@ -205,7 +205,7 @@ typedef unsigned short UShort;
 
 #ifdef Bad_float_h
 
-#else /* ifndef Bad_float_h */
+#else  /* ifndef Bad_float_h */
 #endif /* Bad_float_h */
 
 #ifdef IEEE_Arith
@@ -354,6 +354,7 @@ _Hide extern const double __gdtoa_tinytens[];
 _Hide extern const unsigned char __gdtoa_hexdig[];
 _Hide extern const char *const __gdtoa_InfName[6];
 _Hide extern const char *const __gdtoa_NanName[3];
+_Hide extern const ULong __gdtoa_NanDflt_Q[4];
 
 Bigint *__gdtoa_Balloc(int, ThInfo **);
 void __gdtoa_Bfree(Bigint *, ThInfo **);