Add Chromium-only Blender WebEngine parity work

blender-5.2.0/extern/gmp-source/mpn/alpha/cntlz.asm

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+dnl  Alpha auxiliary for longlong.h's count_leading_zeros
+
+dnl  Copyright 1997, 2000, 2002 Free Software Foundation, Inc.
+
+dnl  This file is part of the GNU MP Library.
+dnl
+dnl  The GNU MP Library is free software; you can redistribute it and/or modify
+dnl  it under the terms of either:
+dnl
+dnl    * the GNU Lesser General Public License as published by the Free
+dnl      Software Foundation; either version 3 of the License, or (at your
+dnl      option) any later version.
+dnl
+dnl  or
+dnl
+dnl    * the GNU General Public License as published by the Free Software
+dnl      Foundation; either version 2 of the License, or (at your option) any
+dnl      later version.
+dnl
+dnl  or both in parallel, as here.
+dnl
+dnl  The GNU MP Library is distributed in the hope that it will be useful, but
+dnl  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+dnl  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+dnl  for more details.
+dnl
+dnl  You should have received copies of the GNU General Public License and the
+dnl  GNU Lesser General Public License along with the GNU MP Library.  If not,
+dnl  see https://www.gnu.org/licenses/.
+
+include(`../config.m4')
+
+
+ASM_START()
+EXTERN(__clz_tab)
+PROLOGUE(mpn_count_leading_zeros,gp)
+	cmpbge	r31,  r16, r1
+	LEA(r3,__clz_tab)
+	sra	r1,   1,   r1
+	xor	r1,   127, r1
+	srl	r16,  1,   r16
+	addq	r1,   r3,  r1
+	ldq_u	r0,   0(r1)
+	lda	r2,   64
+	extbl	r0,   r1,   r0
+	s8subl	r0,   8,    r0
+	srl	r16,  r0,   r16
+	addq	r16,  r3,   r16
+	ldq_u	r1,   0(r16)
+	extbl	r1,   r16,  r1
+	subq	r2,   r1,   r2
+	subq	r2,   r0,   r0
+	ret	r31,  (r26),1
+EPILOGUE(mpn_count_leading_zeros)
+ASM_END()