Make considerably more progress on AARCH64

- Utilities like pledge.com now build
- kprintf() will no longer balk at 48-bit addresses
- There's a new aarch64-dbg build mode that should work
- gc() and defer() are mostly pacified; avoid using them on aarch64
- THIRD_PART_STB now has Arm Neon intrinsics for fast image handling

test/libc/calls/stat_test.c

@@ -16,10 +16,11 @@
 │ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/calls/struct/stat.h"
+#include "libc/assert.h"
 #include "libc/calls/calls.h"
 #include "libc/calls/internal.h"
 #include "libc/calls/struct/metastat.internal.h"
-#include "libc/calls/struct/stat.h"
 #include "libc/dce.h"
 #include "libc/errno.h"
 #include "libc/mem/gc.internal.h"
@@ -71,16 +72,8 @@ TEST(stat, zipos) {
   EXPECT_SYS(0, 0, stat("/zip/.python/", &st));
 }
 
-static long Stat(const char *path, struct stat *st) {
-  long ax, di, si, dx;
-  asm volatile("syscall"
-               : "=a"(ax), "=D"(di), "=S"(si), "=d"(dx)
-               : "0"(__NR_stat), "1"(path), "2"(st)
-               : "rcx", "r8", "r9", "r10", "r11", "memory", "cc");
-  return ax;
-}
-
 static long Fstatat(const char *path, struct stat *st) {
+#ifdef __x86_64__
   long ax, di, si, dx;
   register long r10 asm("r10") = 0;
   asm volatile("syscall"
@@ -88,6 +81,21 @@ static long Fstatat(const char *path, struct stat *st) {
                : "0"(__NR_fstatat), "1"(AT_FDCWD), "2"(path), "3"(st)
                : "rcx", "r8", "r9", "r11", "memory", "cc");
   return ax;
+#elif defined(__aarch64__)
+  register long r0 asm("x0") = (long)AT_FDCWD;
+  register long r1 asm("x1") = (long)path;
+  register long r2 asm("x2") = (long)st;
+  register long r3 asm("x3") = (long)0;
+  register long r8 asm("x8") = (long)__NR_fstatat;
+  register long res_x0 asm("x0");
+  asm volatile("svc\t0"
+               : "=r"(res_x0)
+               : "r"(r0), "r"(r1), "r"(r2), "r"(r3), "r"(r8)
+               : "memory");
+  return res_x0;
+#else
+#error "unsupported architecture"
+#endif
 }
 
 BENCH(stat, bench) {
@@ -100,10 +108,6 @@ BENCH(stat, bench) {
                    "tokenize_tests-latin1-coding-cookie-and-utf8-bom-sig.txt",
                    0644));
   if (!IsWindows() && !IsFreebsd()) {
-    EZBENCH2("stat syscall", donothing,
-             Stat(".python/test/"
-                  "tokenize_tests-latin1-coding-cookie-and-utf8-bom-sig.txt",
-                  &st));
     EZBENCH2("fstatat syscall", donothing,
              Fstatat(".python/test/"
                      "tokenize_tests-latin1-coding-cookie-and-utf8-bom-sig.txt",