diff --git a/libc/calls/CPU_COUNT_S.c b/libc/calls/CPU_COUNT_S.c
new file mode 100644
index 000000000..c14a9e947
--- /dev/null
+++ b/libc/calls/CPU_COUNT_S.c
@@ -0,0 +1,28 @@
+/*-*- 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 2023 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/calls/struct/cpuset.h"
+#include "libc/intrin/popcnt.h"
+
+int CPU_COUNT_S(size_t size, const cpu_set_t *set) {
+  int i, c = 0;
+  for (i = 0; i < size / sizeof(*set->__bits); i++) {
+    c += popcnt(set->__bits[i]);
+  }
+  return c;
+}
diff --git a/libc/calls/struct/cpuset.h b/libc/calls/struct/cpuset.h
index c0df8bc1c..dafddbb14 100644
--- a/libc/calls/struct/cpuset.h
+++ b/libc/calls/struct/cpuset.h
@@ -17,15 +17,31 @@ int sched_setaffinity(int, size_t, const cpu_set_t *);
 #define CPU_SET(i, s)   ((s)->__bits[(i) / 64] |= 1ull << ((i) % 64))
 #define CPU_CLR(i, s)   ((s)->__bits[(i) / 64] &= ~(1ull << ((i) % 64)))
 #define CPU_ISSET(i, s) (!!((s)->__bits[(i) / 64] & (1ull << ((i) % 64))))
+
 void CPU_ZERO(cpu_set_t *);
+#define CPU_ZERO(x) CPU_ZERO(x)
+
 int CPU_COUNT(cpu_set_t *);
+#define CPU_COUNT(x) CPU_COUNT(x)
+
 int CPU_EQUAL(cpu_set_t *, cpu_set_t *);
+#define CPU_EQUAL(x, y) CPU_EQUAL(x, y)
+
 void CPU_AND(cpu_set_t *, cpu_set_t *, cpu_set_t *);
+#define CPU_AND(x, y, z) CPU_AND(x, y, z)
+
 void CPU_OR(cpu_set_t *, cpu_set_t *, cpu_set_t *);
+#define CPU_OR(x, y, z) CPU_OR(x, y, z)
+
 void CPU_XOR(cpu_set_t *, cpu_set_t *, cpu_set_t *);
+#define CPU_XOR(x, y, z) CPU_XOR(x, y, z)
+
+int CPU_COUNT_S(size_t, const cpu_set_t *);
+#define CPU_COUNT_S(x, y) CPU_COUNT_S(x, y)
 
 #define CPU_ALLOC_SIZE(n) \
   ((((n) + (8 * sizeof(long) - 1)) & -(8 * sizeof(long))) / sizeof(long))
+
 #define CPU_ALLOC(n)                  ((cpu_set_t *)calloc(1, CPU_ALLOC_SIZE(n)))
 #define CPU_FREE(set)                 free(set)
 #define CPU_ZERO_S(size, set)         memset(set, 0, size)
diff --git a/tool/decode/zip.c b/tool/decode/zip.c
index 4370a44a0..063067047 100644
--- a/tool/decode/zip.c
+++ b/tool/decode/zip.c
@@ -29,6 +29,7 @@
 #include "libc/nexgen32e/crc32.h"
 #include "libc/nt/struct/filetime.h"
 #include "libc/stdio/stdio.h"
+#include "libc/stdio/sysparam.h"
 #include "libc/str/str.h"
 #include "libc/sysv/consts/map.h"
 #include "libc/sysv/consts/o.h"
@@ -401,29 +402,31 @@ void ShowCentralDirHeader64(uint8_t *cd) {
 }
 
 uint8_t *GetZipCdir32(const uint8_t *p, size_t n) {
-  size_t i;
+  int64_t i, e;
   if (n >= kZipCdirHdrMinSize) {
     i = n - kZipCdirHdrMinSize;
-    do {
+    e = MAX(0, n - 65536);
+    for (; i >= e; --i) {
       if (READ32LE(p + i) == kZipCdirHdrMagic &&
           IsZipEocd32(p, n, i) == kZipOk) {
         return (/*unconst*/ uint8_t *)(p + i);
       }
-    } while (i--);
+    }
   }
   return NULL;
 }
 
 uint8_t *GetZipCdir64(const uint8_t *p, size_t n) {
-  uint64_t i, j;
+  int64_t e, i, j;
   if (n >= kZipCdir64LocatorSize) {
     i = n - kZipCdir64LocatorSize;
-    do {
+    e = MAX(0, n - 65536);
+    for (; i >= e; --i) {
       if (READ32LE(p + i) == kZipCdir64LocatorMagic &&
           (j = ZIP_LOCATE64_OFFSET(p + i)) + kZipCdir64HdrMinSize <= n) {
         return (uint8_t *)p + j;
       }
-    } while (i--);
+    }
   }
   return NULL;
 }