From 11da511c784eca003deb90c23570f0873954e0de Mon Sep 17 00:00:00 2001
From: Duncan Wilkie <antigravityd@gmail.com>
Date: Sat, 18 Nov 2023 06:11:09 -0600
Subject: Initial commit.

---
 gmp-6.3.0/mpn/x86/k6/mmx/rshift.asm | 130 ++++++++++++++++++++++++++++++++++++
 1 file changed, 130 insertions(+)
 create mode 100644 gmp-6.3.0/mpn/x86/k6/mmx/rshift.asm

(limited to 'gmp-6.3.0/mpn/x86/k6/mmx/rshift.asm')

diff --git a/gmp-6.3.0/mpn/x86/k6/mmx/rshift.asm b/gmp-6.3.0/mpn/x86/k6/mmx/rshift.asm
new file mode 100644
index 0000000..cd0382f
--- /dev/null
+++ b/gmp-6.3.0/mpn/x86/k6/mmx/rshift.asm
@@ -0,0 +1,130 @@
+dnl  AMD K6 mpn_rshift -- mpn right shift.
+
+dnl  Copyright 1999, 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')
+
+
+C K6: 3.0 cycles/limb
+
+
+C mp_limb_t mpn_rshift (mp_ptr dst, mp_srcptr src, mp_size_t size,
+C                       unsigned shift);
+C
+C The loop runs at 3 cycles/limb, limited by decoding and by having 3 mmx
+C instructions.  This is despite every second fetch being unaligned.
+
+
+defframe(PARAM_SHIFT,16)
+defframe(PARAM_SIZE, 12)
+defframe(PARAM_SRC,  8)
+defframe(PARAM_DST,  4)
+deflit(`FRAME',0)
+
+	TEXT
+	ALIGN(32)
+
+PROLOGUE(mpn_rshift)
+deflit(`FRAME',0)
+
+	C The 1 limb case can be done without the push %ebx, but it's then
+	C still the same speed.  The push is left as a free helping hand for
+	C the two_or_more code.
+
+	movl	PARAM_SIZE, %eax
+	pushl	%ebx			FRAME_pushl()
+
+	movl	PARAM_SRC, %ebx
+	decl	%eax
+
+	movl	PARAM_SHIFT, %ecx
+	jnz	L(two_or_more)
+
+	movl	(%ebx), %edx		C src limb
+	movl	PARAM_DST, %ebx
+
+	shrdl(	%cl, %edx, %eax)	C return value
+
+	shrl	%cl, %edx
+
+	movl	%edx, (%ebx)		C dst limb
+	popl	%ebx
+
+	ret
+
+
+	ALIGN(16)	C avoid offset 0x1f
+L(two_or_more):
+	C eax	size-1
+	C ebx	src
+	C ecx	shift
+	C edx
+
+	movl	(%ebx), %edx	C src low limb
+	negl	%ecx
+
+	addl	$32, %ecx	C 32-shift
+	movd	PARAM_SHIFT, %mm6
+
+	shll	%cl, %edx	C retval
+	movl	PARAM_DST, %ecx
+
+	leal	(%ebx,%eax,4), %ebx
+
+	leal	-4(%ecx,%eax,4), %ecx
+	negl	%eax
+
+
+L(simple):
+	C eax	counter (negative)
+	C ebx	&src[size-1]
+	C ecx	&dst[size-1]
+	C edx	retval
+	C
+	C mm0	scratch
+	C mm6	shift
+
+Zdisp(	movq,	0,(%ebx,%eax,4), %mm0)
+	incl	%eax
+
+	psrlq	%mm6, %mm0
+
+Zdisp(	movd,	%mm0, 0,(%ecx,%eax,4))
+	jnz	L(simple)
+
+
+	movq	%mm0, (%ecx)
+	movl	%edx, %eax
+
+	popl	%ebx
+
+	emms
+	ret
+
+EPILOGUE()
-- 
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