diff --git a/build/bootstrap/compile.com b/build/bootstrap/compile.com
index 347df93b0..0073592d8 100755
Binary files a/build/bootstrap/compile.com and b/build/bootstrap/compile.com differ
diff --git a/build/config.mk b/build/config.mk
index e04ca5584..141977aef 100644
--- a/build/config.mk
+++ b/build/config.mk
@@ -69,6 +69,9 @@ CONFIG_CCFLAGS +=		\
 	$(BACKTRACES)		\
 	-O2
 
+TARGET_ARCH ?=			\
+	-msse3
+
 endif
 
 # Debug Mode
@@ -88,7 +91,7 @@ CONFIG_CPPFLAGS +=		\
 CONFIG_CCFLAGS +=		\
 	$(BACKTRACES)		\
 	$(FTRACE)		\
-	-O2
+	-Og
 
 CONFIG_COPTS +=			\
 	$(SECURITY_BLANKETS)	\
diff --git a/examples/walk.c b/examples/walk.c
new file mode 100644
index 000000000..31f5fc405
--- /dev/null
+++ b/examples/walk.c
@@ -0,0 +1,52 @@
+#if 0
+/*─────────────────────────────────────────────────────────────────╗
+│ To the extent possible under law, Justine Tunney has waived      │
+│ all copyright and related or neighboring rights to this file,    │
+│ as it is written in the following disclaimers:                   │
+│   • http://unlicense.org/                                        │
+│   • http://creativecommons.org/publicdomain/zero/1.0/            │
+╚─────────────────────────────────────────────────────────────────*/
+#endif
+#include "libc/calls/calls.h"
+#include "libc/calls/struct/stat.h"
+#include "libc/log/log.h"
+#include "libc/runtime/runtime.h"
+#include "libc/sysv/consts/exit.h"
+#include "third_party/musl/ftw.h"
+
+/**
+ * @fileoverview Directory walker example.
+ * Copied from IEEE Std 1003.1-2017
+ */
+
+static int display_info(const char *fpath, const struct stat *sb, int tflag,
+                        struct FTW *ftwbuf) {
+  printf("%-3s %2d %7jd   %-40s %d %s\n",
+         (tflag == FTW_D)     ? "d"
+         : (tflag == FTW_DNR) ? "dnr"
+         : (tflag == FTW_DP)  ? "dp"
+         : (tflag == FTW_F)   ? (S_ISBLK(sb->st_mode)    ? "f b"
+                                 : S_ISCHR(sb->st_mode)  ? "f c"
+                                 : S_ISFIFO(sb->st_mode) ? "f p"
+                                 : S_ISREG(sb->st_mode)  ? "f r"
+                                 : S_ISSOCK(sb->st_mode) ? "f s"
+                                                         : "f ?")
+         : (tflag == FTW_NS)  ? "ns"
+         : (tflag == FTW_SL)  ? "sl"
+         : (tflag == FTW_SLN) ? "sln"
+                              : "?",
+         ftwbuf->level, (intmax_t)sb->st_size, fpath, ftwbuf->base,
+         fpath + ftwbuf->base);
+  return 0; /* To tell nftw() to continue */
+}
+
+int main(int argc, char *argv[]) {
+  int flags = 0;
+  if (argc > 2 && strchr(argv[2], 'd') != NULL) flags |= FTW_DEPTH;
+  if (argc > 2 && strchr(argv[2], 'p') != NULL) flags |= FTW_PHYS;
+  if (nftw((argc < 2) ? "." : argv[1], display_info, 20, flags) == -1) {
+    perror("nftw");
+    exit(EXIT_FAILURE);
+  }
+  exit(EXIT_SUCCESS);
+}
diff --git a/libc/runtime/fesetround.c b/libc/runtime/fesetround.c
index f55465f35..3b8896c4e 100644
--- a/libc/runtime/fesetround.c
+++ b/libc/runtime/fesetround.c
@@ -18,8 +18,6 @@
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/runtime/fenv.h"
 
-/* TODO(jart): This needs tests. */
-
 /**
  * Sets rounding mode.
  *
diff --git a/libc/runtime/fltrounds.c b/libc/runtime/fltrounds.c
index 3b90c0f41..c3a8920b8 100644
--- a/libc/runtime/fltrounds.c
+++ b/libc/runtime/fltrounds.c
@@ -19,16 +19,18 @@
 #include "libc/runtime/fenv.h"
 
 int __flt_rounds(void) {
-  switch (fegetround()) {
-    case FE_TOWARDZERO:
+  int x87cw;
+  asm("fnstcw\t%0" : "=m"(x87cw));
+  switch ((x87cw & 0x0c00) >> 10) {
+    case FE_TOWARDZERO >> 10:
       return 0;
-    case FE_TONEAREST:
+    case FE_TONEAREST >> 10:
       return 1;
-    case FE_UPWARD:
+    case FE_UPWARD >> 10:
       return 2;
-    case FE_DOWNWARD:
+    case FE_DOWNWARD >> 10:
       return 3;
     default:
-      return -1;
+      unreachable;
   }
 }
diff --git a/libc/testlib/formatfloat.c b/libc/testlib/formatfloat.c
index d515c66ba..0056a8ded 100644
--- a/libc/testlib/formatfloat.c
+++ b/libc/testlib/formatfloat.c
@@ -19,12 +19,9 @@
 #include "libc/fmt/fmt.h"
 #include "libc/mem/mem.h"
 #include "libc/testlib/testlib.h"
+#include "libc/x/x.h"
 #include "third_party/gdtoa/gdtoa.h"
 
 testonly char *testlib_formatfloat(long double x) {
-  char buf[32];
-  char *str = malloc(256);
-  g_xfmt_p(buf, &x, 15, sizeof(buf), 0);
-  sprintf(str, "%Lf (%s)", x, buf);
-  return str;
+  return xasprintf("%.15Lg", x);
 }
diff --git a/libc/tinymath/atanh.c b/libc/tinymath/atanh.c
index 7927aa709..3548943d4 100644
--- a/libc/tinymath/atanh.c
+++ b/libc/tinymath/atanh.c
@@ -22,5 +22,5 @@
  * Returns inverse hyperbolic tangent of 𝑥.
  */
 double atanh(double x) {
-  return log((1 + x) / (1 - x)) / 2;
+  return x ? log((1 + x) / (1 - x)) / 2 : x;
 }
diff --git a/libc/tinymath/atanhf.c b/libc/tinymath/atanhf.c
index 702a4ae34..ef27074bf 100644
--- a/libc/tinymath/atanhf.c
+++ b/libc/tinymath/atanhf.c
@@ -22,5 +22,5 @@
  * Returns inverse hyperbolic tangent of 𝑥.
  */
 float atanhf(float x) {
-  return logf((1 + x) / (1 - x)) / 2;
+  return x ? logf((1 + x) / (1 - x)) / 2 : x;
 }
diff --git a/libc/tinymath/atanhl.c b/libc/tinymath/atanhl.c
index 54baf9bc4..a88347d18 100644
--- a/libc/tinymath/atanhl.c
+++ b/libc/tinymath/atanhl.c
@@ -22,5 +22,5 @@
  * Returns inverse hyperbolic tangent of 𝑥.
  */
 long double atanhl(long double x) {
-  return logl((1 + x) / (1 - x)) / 2;
+  return x ? logl((1 + x) / (1 - x)) / 2 : x;
 }
diff --git a/libc/tinymath/expm1l.S b/libc/tinymath/expm1l.S
index d12f779d6..f5852d861 100644
--- a/libc/tinymath/expm1l.S
+++ b/libc/tinymath/expm1l.S
@@ -19,7 +19,7 @@
 #include "libc/runtime/pc.internal.h"
 #include "libc/macros.internal.h"
 
-//	Returns 𝑒^x-1.
+//	Returns 𝑒^𝑥-𝟷.
 //
 //	@param	𝑥 is an 80-bit long double passed on stack in 16-bytes
 //	@return	result of exponentiation on FPU stack in %st
@@ -27,11 +27,13 @@ expm1l:	push	%rbp
 	mov	%rsp,%rbp
 	.profilable
 	fldt	16(%rbp)
-	fxam					# isinf(x)
+	fxam
 	fstsw	%ax
 	mov	%ah,%al
-	and	$0x45,%ah
-	cmp	$5,%ah
+	and	$(FPU_C3|FPU_C2|FPU_C0)>>8,%ah
+	cmp	$(FPU_C3)>>8,%ah		# !x
+	je	0f
+	cmp	$(FPU_C2|FPU_C0)>>8,%ah		# isinf(x)
 	je	1f
 	fldl2e
 	fmulp	%st,%st(1)
@@ -50,7 +52,7 @@ expm1l:	push	%rbp
 	faddp	%st,%st(1)
 0:	pop	%rbp
 	ret
-1:	test	$2,%al				# signbit(x)
+1:	test	$FPU_C1>>8,%al			# signbit(x)
 	jz	0b
 	fstp	%st
 	fld1
diff --git a/libc/tinymath/powl.c b/libc/tinymath/powl.c
index 9ecdc23dd..e2a58a23b 100644
--- a/libc/tinymath/powl.c
+++ b/libc/tinymath/powl.c
@@ -46,7 +46,11 @@ long double powl(long double x, long double y) {
             return 1;
           }
         } else if (y > 0) {
-          return y == 1 ? x : 0;
+          if (signbit(x) && y == truncl(y) && ((int64_t)y & 1)) {
+            return -0.;
+          } else {
+            return 0;
+          }
         } else if (!y) {
           return 1;
         } else {
diff --git a/libc/tinymath/sinh.c b/libc/tinymath/sinh.c
index 6cab29aa8..f0e998b7e 100644
--- a/libc/tinymath/sinh.c
+++ b/libc/tinymath/sinh.c
@@ -22,5 +22,6 @@
  * Returns hyperbolic sine of 𝑥.
  */
 double sinh(double x) {
+  if (!x) return x;
   return (exp(x) - exp(-x)) / 2;
 }
diff --git a/libc/tinymath/sinhf.c b/libc/tinymath/sinhf.c
index db7088279..73a013c22 100644
--- a/libc/tinymath/sinhf.c
+++ b/libc/tinymath/sinhf.c
@@ -22,5 +22,6 @@
  * Returns hyperbolic sine of 𝑥.
  */
 float sinhf(float x) {
+  if (!x) return x;
   return (expf(x) - expf(-x)) / 2;
 }
diff --git a/libc/tinymath/sinhl.c b/libc/tinymath/sinhl.c
index 16c79e330..c2a09d892 100644
--- a/libc/tinymath/sinhl.c
+++ b/libc/tinymath/sinhl.c
@@ -22,5 +22,6 @@
  * Returns hyperbolic sine of 𝑥.
  */
 long double sinhl(long double x) {
+  if (!x) return x;
   return (expl(x) - expl(-x)) / 2;
 }
diff --git a/libc/tinymath/tanh.c b/libc/tinymath/tanh.c
index 8139d00f0..5ae19c19f 100644
--- a/libc/tinymath/tanh.c
+++ b/libc/tinymath/tanh.c
@@ -22,6 +22,7 @@
  * Returns hyperbolic tangent of 𝑥.
  */
 double tanh(double x) {
+  if (!x) return x;
   if (isinf(x)) return copysign(1, x);
   return sinh(x) / cosh(x);
 }
diff --git a/libc/tinymath/tanhf.c b/libc/tinymath/tanhf.c
index aef44313f..d9f491de7 100644
--- a/libc/tinymath/tanhf.c
+++ b/libc/tinymath/tanhf.c
@@ -22,6 +22,7 @@
  * Returns hyperbolic tangent of 𝑥.
  */
 float tanhf(float x) {
+  if (!x) return x;
   if (isinf(x)) return copysignf(1, x);
   return sinhf(x) / coshf(x);
 }
diff --git a/libc/tinymath/tanhl.c b/libc/tinymath/tanhl.c
index 3c76761bf..7d0a41e01 100644
--- a/libc/tinymath/tanhl.c
+++ b/libc/tinymath/tanhl.c
@@ -22,6 +22,7 @@
  * Returns hyperbolic tangent of 𝑥.
  */
 long double tanhl(long double x) {
+  if (!x) return x;
   if (isinf(x)) return copysignl(1, x);
   return sinhl(x) / coshl(x);
 }
diff --git a/test/libc/tinymath/atan2_test.c b/test/libc/tinymath/atan2_test.c
index 82350d494..976ff5f2f 100644
--- a/test/libc/tinymath/atan2_test.c
+++ b/test/libc/tinymath/atan2_test.c
@@ -282,6 +282,11 @@ TEST(atan2, test) {
                gc(xasprintf("%.15g", atan2(__DBL_MAX__, __DBL_MIN__))));
   EXPECT_STREQ("0.785398163397448",
                gc(xasprintf("%.15g", atan2(__DBL_MAX__, __DBL_MAX__))));
+  EXPECT_STREQ("-0",
+               gc(xasprintf("%.15g", atan2(-0.000000000000001, INFINITY))));
+  EXPECT_STREQ("-0", gc(xasprintf("%.15g", atan2(-1, INFINITY))));
+  EXPECT_STREQ(
+      "-0", gc(xasprintf("%.15g", atan2(-1.7976931348623157e308, INFINITY))));
 }
 
 BENCH(atan2, bench) {
diff --git a/test/libc/tinymath/atanh_test.c b/test/libc/tinymath/atanh_test.c
index 2f7de8c53..f096cc212 100644
--- a/test/libc/tinymath/atanh_test.c
+++ b/test/libc/tinymath/atanh_test.c
@@ -27,6 +27,7 @@
 
 TEST(atanh, test) {
   EXPECT_STREQ("0", gc(xdtoa(atanh(0))));
+  EXPECT_STREQ("-0", gc(xdtoa(atanh(-0.))));
   EXPECT_STREQ(".549306144334055", gc(xdtoa(atanh(.5))));
   EXPECT_STREQ("-.549306144334055", gc(xdtoa(atanh(-.5))));
   EXPECT_STREQ("INFINITY", gc(xdtoa(atanh(+1))));
@@ -37,6 +38,7 @@ TEST(atanh, test) {
 
 TEST(atanhl, test) {
   EXPECT_STREQ("0", gc(xdtoal(atanhl(0))));
+  EXPECT_STREQ("-0", gc(xdtoal(atanhl(-0.))));
   EXPECT_STREQ(".5493061443340548", gc(xdtoal(atanhl(.5))));
   EXPECT_STREQ("-.5493061443340548", gc(xdtoal(atanhl(-.5))));
   EXPECT_STREQ("INFINITY", gc(xdtoal(atanhl(+1))));
@@ -47,6 +49,7 @@ TEST(atanhl, test) {
 
 TEST(atanhf, test) {
   EXPECT_STREQ("0", gc(xdtoaf(atanhf(0))));
+  EXPECT_STREQ("-0", gc(xdtoaf(atanhf(-0.))));
   EXPECT_STREQ(".549306", gc(xdtoaf(atanhf(.5))));
   EXPECT_STREQ("-.549306", gc(xdtoaf(atanhf(-.5))));
   EXPECT_STREQ("INFINITY", gc(xdtoaf(atanhf(+1))));
diff --git a/test/libc/tinymath/expm1_test.c b/test/libc/tinymath/expm1_test.c
index 2da3221c6..2d218a26f 100644
--- a/test/libc/tinymath/expm1_test.c
+++ b/test/libc/tinymath/expm1_test.c
@@ -25,11 +25,37 @@
 #define expm1(x)  expm1(VEIL("x", (double)(x)))
 #define expm1f(x) expm1f(VEIL("x", (float)(x)))
 
+TEST(expm1, test) {
+  EXPECT_STREQ("0", gc(xdtoa(expm1(0))));
+  EXPECT_STREQ("-0", gc(xdtoa(expm1(-0.))));
+  EXPECT_STREQ("NAN", gc(xdtoa(expm1(NAN))));
+  EXPECT_STREQ("-1", gc(xdtoa(expm1(-INFINITY))));
+  EXPECT_STREQ("INFINITY", gc(xdtoa(expm1(INFINITY))));
+  /* EXPECT_STREQ("-INFINITY", gc(xdtoa(expm1(-132098844872390)))); */
+  /* EXPECT_STREQ("INFINITY", gc(xdtoa(expm1(132098844872390)))); */
+  EXPECT_STREQ("0", gc(xasprintf("%.15g", expm1(0.))));
+  EXPECT_STREQ("-0", gc(xasprintf("%.15g", expm1(-0.))));
+  EXPECT_STREQ("0.648721270700128", gc(xasprintf("%.15g", expm1(.5))));
+  EXPECT_STREQ("-0.393469340287367", gc(xasprintf("%.15g", expm1(-.5))));
+  EXPECT_STREQ("1.71828182845905", gc(xasprintf("%.15g", expm1(1.))));
+  EXPECT_STREQ("-0.632120558828558", gc(xasprintf("%.15g", expm1(-1.))));
+  EXPECT_STREQ("3.48168907033806", gc(xasprintf("%.15g", expm1(1.5))));
+  EXPECT_STREQ("-0.77686983985157", gc(xasprintf("%.15g", expm1(-1.5))));
+  EXPECT_STREQ("6.38905609893065", gc(xasprintf("%.15g", expm1(2.))));
+  EXPECT_TRUE(isnan(expm1(NAN)));
+  EXPECT_TRUE(isnan(expm1(-NAN)));
+  EXPECT_STREQ("inf", gc(xasprintf("%.15g", expm1(INFINITY))));
+  EXPECT_STREQ("-1", gc(xasprintf("%.15g", expm1(-INFINITY))));
+  EXPECT_STREQ("2.2250738585072e-308",
+               gc(xasprintf("%.15g", expm1(__DBL_MIN__))));
+  EXPECT_STREQ("inf", gc(xasprintf("%.15g", expm1(__DBL_MAX__))));
+}
+
 TEST(expm1l, test) {
   EXPECT_STREQ("1.718281828459045", gc(xdtoal(expm1l(1))));
   EXPECT_STREQ("1.718281828459045", gc(xdtoal(expl(1) - 1)));
   EXPECT_STREQ("0", gc(xdtoal(expm1l(0))));
-  EXPECT_STREQ("0", gc(xdtoal(expm1l(-0.))));
+  EXPECT_STREQ("-0", gc(xdtoal(expm1l(-0.))));
   EXPECT_STREQ("NAN", gc(xdtoal(expm1l(NAN))));
   EXPECT_STREQ("-1", gc(xdtoal(expm1l(-INFINITY))));
   EXPECT_STREQ("INFINITY", gc(xdtoal(expm1l(INFINITY))));
@@ -37,19 +63,9 @@ TEST(expm1l, test) {
   /* EXPECT_STREQ("INFINITY", gc(xdtoal(expm1l(132098844872390)))); */
 }
 
-TEST(expm1, test) {
-  EXPECT_STREQ("0", gc(xdtoa(expm1(0))));
-  EXPECT_STREQ("0", gc(xdtoa(expm1(-0.))));
-  EXPECT_STREQ("NAN", gc(xdtoa(expm1(NAN))));
-  EXPECT_STREQ("-1", gc(xdtoa(expm1(-INFINITY))));
-  EXPECT_STREQ("INFINITY", gc(xdtoa(expm1(INFINITY))));
-  /* EXPECT_STREQ("-INFINITY", gc(xdtoa(expm1(-132098844872390)))); */
-  /* EXPECT_STREQ("INFINITY", gc(xdtoa(expm1(132098844872390)))); */
-}
-
 TEST(expm1f, test) {
   EXPECT_STREQ("0", gc(xdtoaf(expm1f(0))));
-  EXPECT_STREQ("0", gc(xdtoaf(expm1f(-0.))));
+  EXPECT_STREQ("-0", gc(xdtoaf(expm1f(-0.))));
   EXPECT_STREQ("NAN", gc(xdtoaf(expm1f(NAN))));
   EXPECT_STREQ("-1", gc(xdtoaf(expm1f(-INFINITY))));
   EXPECT_STREQ("INFINITY", gc(xdtoaf(expm1f(INFINITY))));
diff --git a/test/libc/tinymath/powl_test.c b/test/libc/tinymath/powl_test.c
index 971ecf22b..2922692f0 100644
--- a/test/libc/tinymath/powl_test.c
+++ b/test/libc/tinymath/powl_test.c
@@ -100,6 +100,8 @@ TEST(powl, test) {
   EXPECT_TRUE(isnan(powl(-3, -(1. / MAX(rando, 2)))));
   EXPECT_STREQ("-.3333333333333333", gc(xdtoal(powl(-3, -1))));
   EXPECT_STREQ(".1111111111111111", gc(xdtoal(powl(-3, -2))));
+  EXPECT_STREQ("-0", gc(xdtoal(powl(-0., MAX(1, rando) | 1))));
+  EXPECT_STREQ("0", gc(xdtoal(powl(-0., MAX(1, rando) & ~1))));
 }
 
 TEST(pow, test) {
@@ -150,6 +152,8 @@ TEST(pow, test) {
   EXPECT_STREQ("inf", fmtd(pow(-0., -(rando & -2))));
   EXPECT_STREQ("-0.333333333333333", fmtd(pow(-3, -1)));
   EXPECT_STREQ("0.111111111111111", fmtd(pow(-3, -2)));
+  EXPECT_STREQ("-0", gc(xdtoa(pow(-0., MAX(1, rando) | 1))));
+  EXPECT_STREQ("0", gc(xdtoa(pow(-0., MAX(1, rando) & ~1))));
 }
 
 TEST(powf, test) {
@@ -200,6 +204,8 @@ TEST(powf, test) {
   EXPECT_STREQ("inf", fmtf(powf(-0., -(rando & -2))));
   EXPECT_STREQ("-0.333333", fmtf(powf(-3, -1)));
   EXPECT_STREQ("0.111111", fmtf(powf(-3, -2)));
+  EXPECT_STREQ("-0", gc(xdtoaf(powf(-0., MAX(1, rando) | 1))));
+  EXPECT_STREQ("0", gc(xdtoaf(powf(-0., MAX(1, rando) & ~1))));
 }
 
 TEST(powl, errors) {
@@ -537,6 +543,15 @@ TEST(powl, errors) {
   errno = 0;
   EXPECT_STREQ("inf", fmtd(pow(__DBL_MAX__, __DBL_MAX__)));
   /* EXPECT_EQ(ERANGE, errno); */
+  EXPECT_STREQ("1", gc(xasprintf("%.15g", pow(0., 0))));
+  EXPECT_STREQ("1", gc(xasprintf("%.15g", pow(-0., 0))));
+  EXPECT_STREQ("-0", gc(xasprintf("%.15g", pow(-0., 1))));
+  EXPECT_STREQ("-0", gc(xasprintf("%.15g", pow(-0., 11))));
+  EXPECT_STREQ("-0", gc(xasprintf("%.15g", pow(-0., 111))));
+  EXPECT_STREQ("0", gc(xasprintf("%.15g", pow(-0., 2))));
+  EXPECT_STREQ("0", gc(xasprintf("%.15g", pow(-0., 22))));
+  EXPECT_STREQ("0", gc(xasprintf("%.15g", pow(-0., 222))));
+  EXPECT_STREQ("0", gc(xasprintf("%.15g", pow(-0., 2.5))));
 }
 
 BENCH(powl, bench) {
diff --git a/test/libc/tinymath/sinh_test.c b/test/libc/tinymath/sinh_test.c
index 6cdbe9845..653bb560b 100644
--- a/test/libc/tinymath/sinh_test.c
+++ b/test/libc/tinymath/sinh_test.c
@@ -31,6 +31,7 @@ TEST(sinh, test) {
   EXPECT_STREQ("INFINITY", gc(xdtoa(sinh(30000))));
   EXPECT_STREQ("-INFINITY", gc(xdtoa(sinh(-30000))));
   EXPECT_STREQ("0", gc(xdtoa(sinh(0))));
+  EXPECT_STREQ("-0", gc(xdtoa(sinh(-0.))));
   EXPECT_STREQ("NAN", gc(xdtoa(sinh(NAN))));
   EXPECT_STREQ("INFINITY", gc(xdtoa(sinh(INFINITY))));
   EXPECT_STREQ("-INFINITY", gc(xdtoa(sinh(-INFINITY))));
@@ -42,6 +43,7 @@ TEST(sinhl, test) {
   EXPECT_STREQ("INFINITY", gc(xdtoal(sinhl(30000))));
   EXPECT_STREQ("-INFINITY", gc(xdtoal(sinhl(-30000))));
   EXPECT_STREQ("0", gc(xdtoal(sinhl(0))));
+  EXPECT_STREQ("-0", gc(xdtoal(sinhl(-0.))));
   EXPECT_STREQ("NAN", gc(xdtoal(sinhl(NAN))));
   EXPECT_STREQ("INFINITY", gc(xdtoal(sinhl(INFINITY))));
   EXPECT_STREQ("-INFINITY", gc(xdtoal(sinhl(-INFINITY))));
@@ -53,6 +55,7 @@ TEST(sinhf, test) {
   EXPECT_STREQ("INFINITY", gc(xdtoaf(sinhf(30000))));
   EXPECT_STREQ("-INFINITY", gc(xdtoaf(sinhf(-30000))));
   EXPECT_STREQ("0", gc(xdtoaf(sinhf(0))));
+  EXPECT_STREQ("-0", gc(xdtoaf(sinhf(-0.))));
   EXPECT_STREQ("NAN", gc(xdtoaf(sinhf(NAN))));
   EXPECT_STREQ("INFINITY", gc(xdtoaf(sinhf(INFINITY))));
   EXPECT_STREQ("-INFINITY", gc(xdtoaf(sinhf(-INFINITY))));
diff --git a/test/libc/tinymath/strtod_test.c b/test/libc/tinymath/strtod_test.c
new file mode 100644
index 000000000..f6ee4fdc8
--- /dev/null
+++ b/test/libc/tinymath/strtod_test.c
@@ -0,0 +1,57 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2021 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ Permission to use, copy, modify, and/or distribute this software for         │
+│ any purpose with or without fee is hereby granted, provided that the         │
+│ above copyright notice and this permission notice appear in all copies.      │
+│                                                                              │
+│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
+│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
+│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
+│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, 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/runtime/fenv.h"
+#include "libc/runtime/gc.internal.h"
+#include "libc/testlib/testlib.h"
+#include "libc/x/x.h"
+#include "third_party/gdtoa/gdtoa.h"
+
+int oldround;
+
+void SetUp(void) {
+  oldround = fegetround();
+}
+
+void TearDown(void) {
+  fesetround(oldround);
+}
+
+TEST(strtod, testNearest) {
+  fesetround(FE_TONEAREST);
+  EXPECT_STREQ("-1.79769313486231e+308",
+               gc(xasprintf("%.15g", strtod("-1.79769313486231e+308", NULL))));
+}
+
+TEST(strtod, testDownward) {
+  fesetround(FE_DOWNWARD);
+  EXPECT_STREQ("-1.79769313486232e+308",
+               gc(xasprintf("%.15g", strtod("-1.79769313486231e+308", NULL))));
+}
+
+TEST(strtod, testUpward) {
+  fesetround(FE_UPWARD);
+  EXPECT_STREQ("-1.7976931348623e+308",
+               gc(xasprintf("%.15g", strtod("-1.79769313486231e+308", NULL))));
+}
+
+TEST(strtod, testTowardzero) {
+  fesetround(FE_TOWARDZERO);
+  EXPECT_STREQ("-1.7976931348623e+308",
+               gc(xasprintf("%.15g", strtod("-1.79769313486231e+308", NULL))));
+}
diff --git a/test/libc/tinymath/tanh_test.c b/test/libc/tinymath/tanh_test.c
index b1a59544d..65f922d0f 100644
--- a/test/libc/tinymath/tanh_test.c
+++ b/test/libc/tinymath/tanh_test.c
@@ -29,6 +29,7 @@ TEST(tanhl, test) {
   EXPECT_STREQ(".09966799462495582", gc(xdtoal(tanhl(+.1))));
   EXPECT_STREQ("-.09966799462495582", gc(xdtoal(tanhl(-.1))));
   EXPECT_STREQ("0", gc(xdtoal(tanhl(0))));
+  EXPECT_STREQ("-0", gc(xdtoal(tanhl(-0.))));
   EXPECT_TRUE(isnan(tanhl(NAN)));
   EXPECT_STREQ("1", gc(xdtoal(tanhl(INFINITY))));
   EXPECT_STREQ("-1", gc(xdtoal(tanhl(-INFINITY))));
@@ -38,6 +39,7 @@ TEST(tanh, test) {
   EXPECT_STREQ(".0996679946249559", gc(xdtoa(tanh(+.1))));
   EXPECT_STREQ("-.0996679946249559", gc(xdtoa(tanh(-.1))));
   EXPECT_STREQ("0", gc(xdtoa(tanh(0))));
+  EXPECT_STREQ("-0", gc(xdtoa(tanh(-0.))));
   EXPECT_TRUE(isnan(tanh(NAN)));
   EXPECT_STREQ("1", gc(xdtoa(tanh(INFINITY))));
   EXPECT_STREQ("-1", gc(xdtoa(tanh(-INFINITY))));
@@ -47,6 +49,7 @@ TEST(tanhf, test) {
   EXPECT_STREQ(".099668", gc(xdtoaf(tanhf(+.1))));
   EXPECT_STREQ("-.099668", gc(xdtoaf(tanhf(-.1))));
   EXPECT_STREQ("0", gc(xdtoaf(tanhf(0))));
+  EXPECT_STREQ("-0", gc(xdtoaf(tanhf(-0.))));
   EXPECT_TRUE(isnan(tanhf(NAN)));
   EXPECT_STREQ("1", gc(xdtoaf(tanhf(INFINITY))));
   EXPECT_STREQ("-1", gc(xdtoaf(tanhf(-INFINITY))));
diff --git a/test/libc/tinymath/test.mk b/test/libc/tinymath/test.mk
index 641693130..4feea7a30 100644
--- a/test/libc/tinymath/test.mk
+++ b/test/libc/tinymath/test.mk
@@ -37,7 +37,8 @@ TEST_LIBC_TINYMATH_DIRECTDEPS =					\
 	LIBC_TESTLIB						\
 	LIBC_TINYMATH						\
 	LIBC_UNICODE						\
-	LIBC_X
+	LIBC_X							\
+	THIRD_PARTY_GDTOA
 
 TEST_LIBC_TINYMATH_DEPS :=					\
 	$(call uniq,$(foreach x,$(TEST_LIBC_TINYMATH_DIRECTDEPS),$($(x))))
diff --git a/third_party/gdtoa/gdtoa.internal.h b/third_party/gdtoa/gdtoa.internal.h
index 0a74b0556..970015a47 100644
--- a/third_party/gdtoa/gdtoa.internal.h
+++ b/third_party/gdtoa/gdtoa.internal.h
@@ -18,6 +18,9 @@ asm(".include \"libc/disclaimer.inc\"");
 #define d_QNAN0          0x7ff80000
 #define d_QNAN1          0x0
 
+#define Check_FLT_ROUNDS 1
+#define Trust_FLT_ROUNDS 1
+
 /****************************************************************
 
 The author of this software is David M. Gay.
diff --git a/third_party/gdtoa/gdtoa.mk b/third_party/gdtoa/gdtoa.mk
index d9e15e57b..c253ef9a6 100644
--- a/third_party/gdtoa/gdtoa.mk
+++ b/third_party/gdtoa/gdtoa.mk
@@ -46,13 +46,6 @@ $(THIRD_PARTY_GDTOA_A).pkg:				\
 		$(THIRD_PARTY_GDTOA_A_OBJS)		\
 		$(foreach x,$(THIRD_PARTY_GDTOA_A_DIRECTDEPS),$($(x)_A).pkg)
 
-$(THIRD_PARTY_GDTOA_A_OBJS):				\
-	OVERRIDE_CFLAGS +=				\
-		$(OLD_CODE)				\
-		$(IEEE_MATH)				\
-		-ffunction-sections			\
-		-fdata-sections
-
 THIRD_PARTY_GDTOA_LIBS = $(foreach x,$(THIRD_PARTY_GDTOA_ARTIFACTS),$($(x)))
 THIRD_PARTY_GDTOA_SRCS = $(foreach x,$(THIRD_PARTY_GDTOA_ARTIFACTS),$($(x)_SRCS))
 THIRD_PARTY_GDTOA_HDRS = $(foreach x,$(THIRD_PARTY_GDTOA_ARTIFACTS),$($(x)_HDRS))
diff --git a/third_party/gdtoa/strtod.c b/third_party/gdtoa/strtod.c
index 1080b6b34..19f2de989 100644
--- a/third_party/gdtoa/strtod.c
+++ b/third_party/gdtoa/strtod.c
@@ -729,7 +729,7 @@ strtod(CONST char *s00, char **se)
 				}
 #endif /*Sudden_Underflow*/
 #endif /*Avoid_Underflow*/
-			dval(&adj) *= ulp(&rv);
+			dval(&adj) *= ulp(&rv); /* XXX */
 			if (dsign) {
 				if (word0(&rv) == Big0 && word1(&rv) == Big1)
 					goto ovfl;
diff --git a/third_party/lua/lua.mk b/third_party/lua/lua.mk
index b2628de9b..50a78b0ec 100644
--- a/third_party/lua/lua.mk
+++ b/third_party/lua/lua.mk
@@ -41,7 +41,7 @@ THIRD_PARTY_LUA_DEPS :=					\
 $(THIRD_PARTY_LUA_A):					\
 		third_party/lua/			\
 		$(THIRD_PARTY_LUA_A).pkg		\
-		$(filter-out %/lua.c,$(THIRD_PARTY_LUA_OBJS))
+		$(filter-out %/lua.o,$(THIRD_PARTY_LUA_OBJS))
 
 $(THIRD_PARTY_LUA_A).pkg:				\
 		$(THIRD_PARTY_LUA_OBJS)			\
diff --git a/third_party/musl/ftw.c b/third_party/musl/ftw.c
index ee4c54b22..51622cb51 100644
--- a/third_party/musl/ftw.c
+++ b/third_party/musl/ftw.c
@@ -34,6 +34,12 @@ asm(".include \"libc/disclaimer.inc\"");
 
 /* clang-format off */
 
+/**
+ * Walks file tree.
+ *
+ * @see examples/walk.c for example
+ * @see nftw()
+ */
 int ftw(const char *path, int (*fn)(const char *, const struct stat *, int), int fd_limit)
 {
 	/* The following cast assumes that calling a function with one
diff --git a/third_party/musl/nftw.c b/third_party/musl/nftw.c
index 15a491df8..21d31ff51 100644
--- a/third_party/musl/nftw.c
+++ b/third_party/musl/nftw.c
@@ -38,7 +38,13 @@ Musl libc (MIT License)\\n\
 Copyright 2005-2014 Rich Felker, et. al.\"");
 asm(".include \"libc/disclaimer.inc\"");
 
-#define pthread_setcancelstate(...) /* no cosmo pthreads support atm */
+/* no reason to impose windows limit
+   small enough to fit in stack frame
+   should be changed to use realloc */
+#define PATH_MAX2 2048
+
+/* no cosmo pthreads support atm */
+#define pthread_setcancelstate(...)
 
 /* clang-format off */
 
@@ -123,7 +129,7 @@ static int do_nftw(char *path, int (*fn)(const char *, const struct stat *, int,
 				 && (!de->d_name[1]
 				  || (de->d_name[1]=='.'
 				   && !de->d_name[2]))) continue;
-				if (strlen(de->d_name) >= PATH_MAX-l) {
+				if (strlen(de->d_name) >= PATH_MAX2-l) {
 					errno = ENAMETOOLONG;
 					closedir(d);
 					return -1;
@@ -149,16 +155,21 @@ static int do_nftw(char *path, int (*fn)(const char *, const struct stat *, int,
 	return 0;
 }
 
+/**
+ * Walks file tree.
+ *
+ * @see examples/walk.c for example
+ */
 int nftw(const char *path, int (*fn)(const char *, const struct stat *, int, struct FTW *), int fd_limit, int flags)
 {
 	int r, cs;
 	size_t l;
-	char pathbuf[PATH_MAX+1];
+	char pathbuf[PATH_MAX2+1];
 
 	if (fd_limit <= 0) return 0;
 
 	l = strlen(path);
-	if (l > PATH_MAX) {
+	if (l > PATH_MAX2) {
 		errno = ENAMETOOLONG;
 		return -1;
 	}
diff --git a/third_party/quickjs/README.cosmo b/third_party/quickjs/README.cosmo
index 072d819e9..c8f7ab916 100644
--- a/third_party/quickjs/README.cosmo
+++ b/third_party/quickjs/README.cosmo
@@ -1,2 +1,7 @@
 Source:
-https://bellard.org/quickjs/quickjs-2021-03-27.tar.xz
+- https://bellard.org/quickjs/quickjs-2021-03-27.tar.xz
+
+Local Changes:
+- Replace snprintf with xasprintf in find_unique_cname
+- Squash uninitialized read of harnessbuf in run-test262.c
+- Change run-test262.c to not rebase configured paths
diff --git a/third_party/quickjs/quickjs-libc.c b/third_party/quickjs/quickjs-libc.c
index 32dcc53f8..cea3b1bad 100644
--- a/third_party/quickjs/quickjs-libc.c
+++ b/third_party/quickjs/quickjs-libc.c
@@ -2764,61 +2764,6 @@ static char **build_envp(JSContext *ctx, JSValueConst obj)
     goto done;
 }
 
-/* execvpe is not available on non GNU systems */
-static int my_execvpe(const char *filename, char **argv, char **envp)
-{
-    char *path, *p, *p_next, *p1;
-    char buf[PATH_MAX];
-    size_t filename_len, path_len;
-    BOOL eacces_error;
-    
-    filename_len = strlen(filename);
-    if (filename_len == 0) {
-        errno = ENOENT;
-        return -1;
-    }
-    if (strchr(filename, '/'))
-        return execve(filename, argv, envp);
-    
-    path = getenv("PATH");
-    if (!path)
-        path = (char *)"/bin:/usr/bin";
-    eacces_error = FALSE;
-    p = path;
-    for(p = path; p != NULL; p = p_next) {
-        p1 = strchr(p, ':');
-        if (!p1) {
-            p_next = NULL;
-            path_len = strlen(p);
-        } else {
-            p_next = p1 + 1;
-            path_len = p1 - p;
-        }
-        /* path too long */
-        if ((path_len + 1 + filename_len + 1) > PATH_MAX)
-            continue;
-        memcpy(buf, p, path_len);
-        buf[path_len] = '/';
-        memcpy(buf + path_len + 1, filename, filename_len);
-        buf[path_len + 1 + filename_len] = '\0';
-        
-        execve(buf, argv, envp);
-
-        if (errno == EACCES) {
-          eacces_error = TRUE;
-        } else if (errno == ENOENT) {
-          /* do nothing */
-        } else if (errno == ENOTDIR) {
-          /* do nothing */
-        } else {
-          return -1;
-        }
-    }
-    if (eacces_error)
-        errno = EACCES;
-    return -1;
-}
-
 /* exec(args[, options]) -> exitcode */
 static JSValue js_os_exec(JSContext *ctx, JSValueConst this_val,
                           int argc, JSValueConst *argv)
@@ -2973,7 +2918,7 @@ static JSValue js_os_exec(JSContext *ctx, JSValueConst this_val,
         if (!file)
             file = exec_argv[0];
         if (use_path)
-            ret = my_execvpe(file, (char **)exec_argv, envp);
+            ret = execvpe(file, (char **)exec_argv, envp);
         else
             ret = execve(file, (char **)exec_argv, envp);
         _exit(127);
diff --git a/third_party/quickjs/quickjs.c b/third_party/quickjs/quickjs.c
index bcec9cc48..1935e0cec 100644
--- a/third_party/quickjs/quickjs.c
+++ b/third_party/quickjs/quickjs.c
@@ -11296,11 +11296,11 @@ static char *i64toa(char *buf_end, int64_t n, unsigned int base)
 static void js_ecvt1(double d, int n_digits, int *decpt, int *sign, char *buf,
                      int rounding_mode, char *buf1, int buf1_size)
 {
-    /* if (rounding_mode != FE_TONEAREST) */
-    /*     fesetround(rounding_mode); */
+    if (rounding_mode != FE_TONEAREST)
+        fesetround(rounding_mode);
     snprintf(buf1, buf1_size, "%+.*e", n_digits - 1, d);
-    /* if (rounding_mode != FE_TONEAREST) */
-    /*     fesetround(FE_TONEAREST); */
+    if (rounding_mode != FE_TONEAREST)
+        fesetround(FE_TONEAREST);
     *sign = (buf1[0] == '-');
     /* mantissa */
     buf[0] = buf1[1];
@@ -53608,12 +53608,12 @@ static JSValue js_atomics_op(JSContext *ctx,
         a = func_name((_Atomic(uint32_t) *)ptr, v);     \
         break;
 #endif
-        /* OP(ADD, atomic_fetch_add) */
-        /* OP(AND, atomic_fetch_and) */
-        /* OP(OR, atomic_fetch_or) */
-        /* OP(SUB, atomic_fetch_sub) */
-        /* OP(XOR, atomic_fetch_xor) */
-        /* OP(EXCHANGE, atomic_exchange) */
+        OP(ADD, atomic_fetch_add)
+        OP(AND, atomic_fetch_and)
+        OP(OR, atomic_fetch_or)
+        OP(SUB, atomic_fetch_sub)
+        OP(XOR, atomic_fetch_xor)
+        OP(EXCHANGE, atomic_exchange)
 #undef OP
 
     case ATOMICS_OP_LOAD | (0 << 3):
diff --git a/third_party/quickjs/quickjs.mk b/third_party/quickjs/quickjs.mk
index 494e1d93f..f278b6eb5 100644
--- a/third_party/quickjs/quickjs.mk
+++ b/third_party/quickjs/quickjs.mk
@@ -3,83 +3,151 @@
 
 PKGS += THIRD_PARTY_QUICKJS
 
-THIRD_PARTY_QUICKJS_FILES := $(wildcard third_party/quickjs/*)
-THIRD_PARTY_QUICKJS_SRCS = $(filter %.c,$(THIRD_PARTY_QUICKJS_FILES))
-THIRD_PARTY_QUICKJS_HDRS = $(filter %.h,$(THIRD_PARTY_QUICKJS_FILES))
+THIRD_PARTY_QUICKJS_ARTIFACTS += THIRD_PARTY_QUICKJS_A
 THIRD_PARTY_QUICKJS_BINS = $(THIRD_PARTY_QUICKJS_COMS) $(THIRD_PARTY_QUICKJS_COMS:%=%.dbg)
-THIRD_PARTY_QUICKJS = $(THIRD_PARTY_QUICKJS_DEPS) $(THIRD_PARTY_QUICKJS_A)
+THIRD_PARTY_QUICKJS = $(THIRD_PARTY_QUICKJS_A_DEPS) $(THIRD_PARTY_QUICKJS_A)
 THIRD_PARTY_QUICKJS_A = o/$(MODE)/third_party/quickjs/quickjs.a
+THIRD_PARTY_QUICKJS_HDRS = $(foreach x,$(THIRD_PARTY_QUICKJS_ARTIFACTS),$($(x)_HDRS))
 
-THIRD_PARTY_QUICKJS_OBJS =				\
-	$(THIRD_PARTY_QUICKJS_SRCS:%.c=o/$(MODE)/%.o)
+THIRD_PARTY_QUICKJS_A_SRCS =					\
+	third_party/quickjs/cutils.c				\
+	third_party/quickjs/libbf.c				\
+	third_party/quickjs/libregexp.c				\
+	third_party/quickjs/libunicode.c			\
+	third_party/quickjs/quickjs-libc.c			\
+	third_party/quickjs/quickjs.c				\
+	third_party/quickjs/wut.c
 
-THIRD_PARTY_QUICKJS_COMS =				\
-	o/$(MODE)/third_party/quickjs/qjs.com
+THIRD_PARTY_QUICKJS_A_HDRS =					\
+	third_party/quickjs/cutils.h				\
+	third_party/quickjs/libbf.h				\
+	third_party/quickjs/libregexp.h				\
+	third_party/quickjs/libunicode.h			\
+	third_party/quickjs/list.h				\
+	third_party/quickjs/quickjs-libc.h			\
+	third_party/quickjs/quickjs.h
 
-THIRD_PARTY_QUICKJS_CHECKS =				\
-	$(THIRD_PARTY_QUICKJS_A).pkg			\
-	$(THIRD_PARTY_QUICKJS_HDRS:%=o/$(MODE)/%.ok)
+THIRD_PARTY_QUICKJS_A_OBJS =					\
+	o/$(MODE)/third_party/quickjs/cutils.o			\
+	o/$(MODE)/third_party/quickjs/libbf.o			\
+	o/$(MODE)/third_party/quickjs/libregexp.o		\
+	o/$(MODE)/third_party/quickjs/libunicode.o		\
+	o/$(MODE)/third_party/quickjs/quickjs-libc.o		\
+	o/$(MODE)/third_party/quickjs/quickjs.o			\
+	o/$(MODE)/third_party/quickjs/wut.o
 
-THIRD_PARTY_QUICKJS_DIRECTDEPS =			\
-	LIBC_ALG					\
-	LIBC_CALLS					\
-	LIBC_FMT					\
-	LIBC_INTRIN					\
-	LIBC_LOG					\
-	LIBC_MEM					\
-	LIBC_NEXGEN32E					\
-	LIBC_RUNTIME					\
-	LIBC_SOCK					\
-	LIBC_STDIO					\
-	LIBC_STR					\
-	LIBC_SYSV					\
-	LIBC_SYSV_CALLS					\
-	LIBC_TIME					\
-	LIBC_TINYMATH					\
-	LIBC_UNICODE					\
-	LIBC_X						\
-	THIRD_PARTY_COMPILER_RT				\
-	THIRD_PARTY_GDTOA				\
-	THIRD_PARTY_GETOPT				\
+THIRD_PARTY_QUICKJS_A_DIRECTDEPS =				\
+	LIBC_ALG						\
+	LIBC_CALLS						\
+	LIBC_FMT						\
+	LIBC_INTRIN						\
+	LIBC_LOG						\
+	LIBC_MEM						\
+	LIBC_NEXGEN32E						\
+	LIBC_RUNTIME						\
+	LIBC_SOCK						\
+	LIBC_STDIO						\
+	LIBC_STR						\
+	LIBC_SYSV						\
+	LIBC_SYSV_CALLS						\
+	LIBC_TIME						\
+	LIBC_TINYMATH						\
+	LIBC_UNICODE						\
+	LIBC_X							\
+	THIRD_PARTY_COMPILER_RT					\
+	THIRD_PARTY_GDTOA					\
+	THIRD_PARTY_GETOPT					\
 	THIRD_PARTY_MUSL
 
-THIRD_PARTY_QUICKJS_DEPS :=				\
-	$(call uniq,$(foreach x,$(THIRD_PARTY_QUICKJS_DIRECTDEPS),$($(x))))
+THIRD_PARTY_QUICKJS_A_DEPS :=					\
+	$(call uniq,$(foreach x,$(THIRD_PARTY_QUICKJS_A_DIRECTDEPS),$($(x))))
 
-$(THIRD_PARTY_QUICKJS_A):				\
-		third_party/quickjs/			\
-		$(THIRD_PARTY_QUICKJS_A).pkg		\
-		$(filter-out %/quickjs.c,$(THIRD_PARTY_QUICKJS_OBJS))
+$(THIRD_PARTY_QUICKJS_A):					\
+		third_party/quickjs/				\
+		$(THIRD_PARTY_QUICKJS_A).pkg			\
+		$(THIRD_PARTY_QUICKJS_A_OBJS)
 
-$(THIRD_PARTY_QUICKJS_A).pkg:				\
-		$(THIRD_PARTY_QUICKJS_OBJS)		\
-		$(foreach x,$(THIRD_PARTY_QUICKJS_DIRECTDEPS),$($(x)_A).pkg)
+$(THIRD_PARTY_QUICKJS_A).pkg:					\
+		$(THIRD_PARTY_QUICKJS_A_OBJS)			\
+		$(foreach x,$(THIRD_PARTY_QUICKJS_A_DIRECTDEPS),$($(x)_A).pkg)
 
-o/$(MODE)/third_party/quickjs/qjs.com.dbg:		\
-		$(THIRD_PARTY_QUICKJS_DEPS)		\
-		$(THIRD_PARTY_QUICKJS_A)		\
-		$(THIRD_PARTY_QUICKJS_A).pkg		\
-		o/$(MODE)/third_party/quickjs/qjs.o	\
-		$(CRT)					\
+THIRD_PARTY_QUICKJS_SRCS =					\
+	third_party/quickjs/qjs.c				\
+	third_party/quickjs/qjsc.c				\
+	third_party/quickjs/run-test262.c			\
+	$(foreach x,$(THIRD_PARTY_QUICKJS_ARTIFACTS),$($(x)_SRCS))
+
+THIRD_PARTY_QUICKJS_OBJS =					\
+	o/$(MODE)/third_party/quickjs/qjs.o			\
+	o/$(MODE)/third_party/quickjs/qjsc.o			\
+	o/$(MODE)/third_party/quickjs/run-test262.o		\
+	$(THIRD_PARTY_QUICKJS_A_OBJS)
+
+THIRD_PARTY_QUICKJS_COMS =					\
+	o/$(MODE)/third_party/quickjs/qjs.com			\
+	o/$(MODE)/third_party/quickjs/qjsc.com			\
+	o/$(MODE)/third_party/quickjs/run-test262.com		\
+	o/$(MODE)/third_party/quickjs/unicode_gen.com
+
+THIRD_PARTY_QUICKJS_CHECKS =					\
+	$(THIRD_PARTY_QUICKJS_A).pkg				\
+	$(THIRD_PARTY_QUICKJS_A_HDRS:%=o/$(MODE)/%.ok)
+
+o/$(MODE)/third_party/quickjs/qjs.com.dbg:			\
+		$(THIRD_PARTY_QUICKJS_A_DEPS)			\
+		$(THIRD_PARTY_QUICKJS_A)			\
+		$(THIRD_PARTY_QUICKJS_A).pkg			\
+		o/$(MODE)/third_party/quickjs/qjs.o		\
+		$(CRT)						\
 		$(APE)
 	-@$(APELINK)
 
-$(THIRD_PARTY_QUICKJS_OBJS):				\
-		OVERRIDE_CPPFLAGS +=			\
-			-DCONFIG_BIGNUM			\
+o/$(MODE)/third_party/quickjs/qjsc.com.dbg:			\
+		$(THIRD_PARTY_QUICKJS_A_DEPS)			\
+		$(THIRD_PARTY_QUICKJS_A)			\
+		$(THIRD_PARTY_QUICKJS_A).pkg			\
+		o/$(MODE)/third_party/quickjs/qjsc.o		\
+		$(CRT)						\
+		$(APE)
+	-@$(APELINK)
+
+# git clone git@github.com:tc39/test262 /opt/test262
+# make -j8 MODE=dbg o/dbg/third_party/quickjs/run-test262.com
+# o/dbg/third_party/quickjs/run-test262.com -m -c third_party/quickjs/test262.conf -a
+o/$(MODE)/third_party/quickjs/run-test262.com.dbg:		\
+		$(THIRD_PARTY_QUICKJS_A_DEPS)			\
+		$(THIRD_PARTY_QUICKJS_A)			\
+		$(THIRD_PARTY_QUICKJS_A).pkg			\
+		o/$(MODE)/third_party/quickjs/run-test262.o	\
+		$(CRT)						\
+		$(APE)
+	-@$(APELINK)
+
+o/$(MODE)/third_party/quickjs/unicode_gen.com.dbg:		\
+		$(THIRD_PARTY_QUICKJS_A_DEPS)			\
+		$(THIRD_PARTY_QUICKJS_A)			\
+		$(THIRD_PARTY_QUICKJS_A).pkg			\
+		o/$(MODE)/third_party/quickjs/unicode_gen.o	\
+		$(CRT)						\
+		$(APE)
+	-@$(APELINK)
+
+$(THIRD_PARTY_QUICKJS_OBJS):					\
+		OVERRIDE_CPPFLAGS +=				\
+			-DCONFIG_BIGNUM				\
 			-DCONFIG_VERSION=\"$(shell cat third_party/quickjs/VERSION)\"
 
-o/$(MODE)/third_party/quickjs/unicode_gen.o:		\
-		OVERRIDE_CPPFLAGS +=			\
+o/$(MODE)/third_party/quickjs/unicode_gen.o:			\
+		OVERRIDE_CPPFLAGS +=				\
 			-DSTACK_FRAME_UNLIMITED
 
 # TODO(jart): Replace alloca() calls with malloc().
-o/$(MODE)/third_party/quickjs/libregexp.o		\
-o/$(MODE)/third_party/quickjs/quickjs.o:		\
-		OVERRIDE_CPPFLAGS +=			\
+o/$(MODE)/third_party/quickjs/libregexp.o			\
+o/$(MODE)/third_party/quickjs/quickjs.o:			\
+		OVERRIDE_CPPFLAGS +=				\
 			-DSTACK_FRAME_UNLIMITED
 
 .PHONY: o/$(MODE)/third_party/quickjs
-o/$(MODE)/third_party/quickjs:				\
-		$(THIRD_PARTY_QUICKJS_BINS)		\
+o/$(MODE)/third_party/quickjs:					\
+		$(THIRD_PARTY_QUICKJS_BINS)			\
 		$(THIRD_PARTY_QUICKJS_CHECKS)
diff --git a/third_party/quickjs/run-test262.c b/third_party/quickjs/run-test262.c
index f69a28f48..756d43aa8 100644
--- a/third_party/quickjs/run-test262.c
+++ b/third_party/quickjs/run-test262.c
@@ -931,7 +931,8 @@ void load_config(const char *filename)
     if (!f) {
         perror_exit(1, filename);
     }
-    base_name = get_basename(filename);
+    /* base_name = get_basename(filename); */
+    base_name = strdup("");
     
     while (fgets(buf, sizeof(buf), f) != NULL) {
         char *p, *q;
@@ -1672,6 +1673,8 @@ int run_test(const char *filename, int index)
             if (p) {
                 snprintf(harnessbuf, sizeof(harnessbuf), "%.*s%s",
                          (int)(p - filename), filename, "test/harness");
+            } else {
+                strcpy(harnessbuf, ""); /* XXX */
             }
             harness = harnessbuf;
         }
@@ -1947,6 +1950,8 @@ int main(int argc, char **argv)
     BOOL is_test262_harness = FALSE;
     BOOL is_module = FALSE;
 
+    showcrashreports();
+
 #if !defined(_WIN32)
     /* Date tests assume California local time */
     setenv("TZ", "America/Los_Angeles", 1);
diff --git a/third_party/quickjs/test262.conf b/third_party/quickjs/test262.conf
index 6fbb5793a..0a181ef30 100644
--- a/third_party/quickjs/test262.conf
+++ b/third_party/quickjs/test262.conf
@@ -26,22 +26,22 @@ module=yes
 verbose=yes
 
 # load harness files from this directory
-harnessdir=test262/harness
+harnessdir=/opt/test262/harness
 
 # names of harness include files to skip
 #harnessexclude=
 
 # name of the error file for known errors
-errorfile=test262_errors.txt
+errorfile=third_party/quickjs/test262_errors.txt
 
 # exclude tests enumerated in this file (see also [exclude] section)
 #excludefile=test262_exclude.txt
 
 # report test results to this file
-reportfile=test262_report.txt
+reportfile=o/test262_report.txt
 
 # enumerate tests from this directory
-testdir=test262/test
+testdir=/opt/test262/test
 
 [features]
 # Standard language features and proposed extensions
@@ -184,16 +184,19 @@ __setter__
 # list excluded tests and directories here
 
 # intl not supported
-test262/test/intl402/
+/opt/test262/test/intl402/
 
 # incompatible with the "caller" feature
-test262/test/built-ins/Function/prototype/restricted-property-caller.js
-test262/test/built-ins/Function/prototype/restricted-property-arguments.js
-test262/test/built-ins/ThrowTypeError/unique-per-realm-function-proto.js
+/opt/test262/test/built-ins/Function/prototype/restricted-property-caller.js
+/opt/test262/test/built-ins/Function/prototype/restricted-property-arguments.js
+/opt/test262/test/built-ins/ThrowTypeError/unique-per-realm-function-proto.js
 
 # slow tests
-#test262/test/built-ins/RegExp/CharacterClassEscapes/
-#test262/test/built-ins/RegExp/property-escapes/
+#/opt/test262/test/built-ins/RegExp/CharacterClassEscapes/
+#/opt/test262/test/built-ins/RegExp/property-escapes/
+
+# No threads in Cosmopolitan ATM
+/opt/test262/test/built-ins/Atomics/
 
 [tests]
 # list test files or use config.testdir
diff --git a/tool/build/compile.c b/tool/build/compile.c
index 647396df4..b52435c5f 100644
--- a/tool/build/compile.c
+++ b/tool/build/compile.c
@@ -421,6 +421,11 @@ int main(int argc, char *argv[]) {
     } else if (isclang && startswith(argv[i], "--debug-prefix-map")) {
       /* llvm doesn't provide a gas interface so simulate w/ clang */
       AddArg(xasprintf("-f%s", argv[i] + 2));
+    } else if (isgcc && (!strcmp(argv[i], "-Os") || !strcmp(argv[i], "-O2") ||
+                         !strcmp(argv[i], "-O3"))) {
+      /* https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97623 */
+      AddArg(argv[i]);
+      AddArg("-fno-code-hoisting");
     } else {
       AddArg(argv[i]);
     }