Make AARCH64 harder, better, faster, stronger

- Perform some housekeeping on scalar math function code
- Import ARM's Optimized Routines for SIMD string processing
- Upgrade to latest Chromium zlib and enable more SIMD optimizations

third_party/zlib/crc32_simd.internal.h

@@ -0,0 +1,57 @@
+#ifndef COSMOPOLITAN_THIRD_PARTY_ZLIB_CRC32_SIMD_INTERNAL_H_
+#define COSMOPOLITAN_THIRD_PARTY_ZLIB_CRC32_SIMD_INTERNAL_H_
+#include "third_party/zlib/deflate.internal.h"
+#include "third_party/zlib/zconf.h"
+#include "third_party/zlib/zutil.internal.h"
+#if !(__ASSEMBLER__ + __LINKER__ + 0)
+COSMOPOLITAN_C_START_
+// clang-format off
+
+/*
+ * crc32_sse42_simd_(): compute the crc32 of the buffer, where the buffer
+ * length must be at least 64, and a multiple of 16.
+ */
+uint32_t ZLIB_INTERNAL crc32_sse42_simd_(const unsigned char* buf,
+                                         z_size_t len,
+                                         uint32_t crc);
+
+uint32_t ZLIB_INTERNAL crc32_avx512_simd_(const unsigned char* buf,
+                                          z_size_t len,
+                                          uint32_t crc);
+
+/*
+ * crc32_sse42_simd_ buffer size constraints: see the use in zlib/crc32.c
+ * for computing the crc32 of an arbitrary length buffer.
+ */
+#define Z_CRC32_SSE42_MINIMUM_LENGTH 64
+#define Z_CRC32_SSE42_CHUNKSIZE_MASK 15
+#define Z_CRC32_AVX512_MINIMUM_LENGTH 256
+#define Z_CRC32_AVX512_CHUNKSIZE_MASK 63
+
+/*
+ * CRC32 checksums using ARMv8-a crypto instructions.
+ */
+uint32_t ZLIB_INTERNAL armv8_crc32_little(const unsigned char* buf,
+                                          z_size_t len,
+                                          uint32_t crc);
+
+/* aarch64 specific code. */
+#if defined(__aarch64__)
+
+/* 128 is the sweet spot at the time of coding (late 2020). */
+#define Z_CRC32_PMULL_MINIMUM_LENGTH 128
+#define Z_CRC32_PMULL_CHUNKSIZE_MASK 15
+
+/*
+ * CRC32 checksums using ARMv8-a PMULL instructions, where the buffer
+ * length must be at least 64, and a multiple of 16.
+ */
+uint32_t ZLIB_INTERNAL armv8_crc32_pmull_little(const unsigned char* buf,
+                                                z_size_t len,
+                                                uint32_t crc);
+
+#endif
+
+COSMOPOLITAN_C_END_
+#endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
+#endif /* COSMOPOLITAN_THIRD_PARTY_ZLIB_CRC32_SIMD_INTERNAL_H_ */