Initial import

libc/nexgen32e/strcmp-hook.S

@@ -0,0 +1,49 @@
+/*-*- mode:asm; indent-tabs-mode:t; tab-width:8; coding:utf-8               -*-│
+│vi: set et ft=asm ts=8 sw=8 fenc=utf-8                                     :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/nexgen32e/x86feature.h"
+#include "libc/dce.h"
+#include "libc/macros.h"
+
+/	Dispatches to fastest strcmp() implementation.
+/
+/	@param	rdi is first non-null NUL-terminated string pointer
+/	@param	rsi is second non-null NUL-terminated string pointer
+/	@return	rax is <0, 0, or >0 based on uint8_t comparison
+/	@asyncsignalsafe
+	.initbss 300,_init_strcmp
+hook$strcmp:
+	.quad	0
+	.endobj	hook$strcmp,globl,hidden
+	.previous
+
+	.init.start 300,_init_strcmp
+#if !IsTiny()
+	ezlea	strcmp$avx,ax
+#if !X86_NEED(AVX)
+	ezlea	tinystrcmp,dx
+	testb	X86_HAVE(AVX)+kCpuids(%rip)
+	cmovz	%rdx,%rax
+#endif /* AVX */
+#else
+	ezlea	tinystrcmp,ax
+#endif /* TINY */
+	stosq
+	.init.end 300,_init_strcmp
+	.yoink	__FILE__