dnl  x86 mpn_bdiv_q_1 -- mpn by limb exact division.

dnl  Rearranged from mpn/x86/dive_1.asm by Marco Bodrato.

dnl  Copyright 2001, 2002, 2007, 2011 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     cycles/limb

C P54    30.0

C P55    29.0

C P6     13.0 odd divisor, 12.0 even (strangely)

C K6     14.0

C K7     12.0

C P4     42.0

MULFUNC_PROLOGUE(mpn_bdiv_q_1 mpn_pi1_bdiv_q_1)

defframe(PARAM_SHIFT,  24)

defframe(PARAM_INVERSE,20)

defframe(PARAM_DIVISOR,16)

defframe(PARAM_SIZE,   12)

defframe(PARAM_SRC,    8)

defframe(PARAM_DST,    4)

dnl  re-use parameter space

define(VAR_INVERSE,`PARAM_SRC')

	TEXT

C mp_limb_t

C mpn_pi1_bdiv_q_1 (mp_ptr dst, mp_srcptr src, mp_size_t size, mp_limb_t divisor,

C		    mp_limb_t inverse, int shift)

	ALIGN(16)

PROLOGUE(mpn_pi1_bdiv_q_1)

deflit(`FRAME',0)

	movl	PARAM_SHIFT, %ecx

	pushl	%ebp	FRAME_pushl()

	movl	PARAM_INVERSE, %eax

	movl	PARAM_SIZE, %ebp

	pushl	%ebx	FRAME_pushl()

L(common):

	pushl	%edi	FRAME_pushl()

	pushl	%esi	FRAME_pushl()

	movl	PARAM_SRC, %esi

	movl	PARAM_DST, %edi

	leal	(%esi,%ebp,4), %esi	C src end

	leal	(%edi,%ebp,4), %edi	C dst end

	negl	%ebp			C -size

	movl	%eax, VAR_INVERSE

	movl	(%esi,%ebp,4), %eax	C src[0]

	xorl	%ebx, %ebx

	xorl	%edx, %edx

	incl	%ebp

	jz	L(one)

	movl	(%esi,%ebp,4), %edx	C src[1]

	shrdl(	%cl, %edx, %eax)

	movl	VAR_INVERSE, %edx

	jmp	L(entry)

	ALIGN(8)

	nop	C k6 code alignment

	nop

L(top):

	C eax	q

	C ebx	carry bit, 0 or -1

	C ecx	shift

	C edx	carry limb

	C esi	src end

	C edi	dst end

	C ebp	counter, limbs, negative

	movl	-4(%esi,%ebp,4), %eax

	subl	%ebx, %edx		C accumulate carry bit

	movl	(%esi,%ebp,4), %ebx

	shrdl(	%cl, %ebx, %eax)

	subl	%edx, %eax		C apply carry limb

	movl	VAR_INVERSE, %edx

	sbbl	%ebx, %ebx

L(entry):

	imull	%edx, %eax

	movl	%eax, -4(%edi,%ebp,4)

	movl	PARAM_DIVISOR, %edx

	mull	%edx

	incl	%ebp

	jnz	L(top)

	movl	-4(%esi), %eax		C src high limb

L(one):

	shrl	%cl, %eax

	popl	%esi	FRAME_popl()

	addl	%ebx, %eax		C apply carry bit

	subl	%edx, %eax		C apply carry limb

	imull	VAR_INVERSE, %eax

	movl	%eax, -4(%edi)

	popl	%edi

	popl	%ebx

	popl	%ebp

	ret

EPILOGUE()

C mp_limb_t mpn_bdiv_q_1 (mp_ptr dst, mp_srcptr src, mp_size_t size,

C                           mp_limb_t divisor);

C

	ALIGN(16)

PROLOGUE(mpn_bdiv_q_1)

deflit(`FRAME',0)

	movl	PARAM_DIVISOR, %eax

	pushl	%ebp	FRAME_pushl()

	movl	$-1, %ecx		C shift count

	movl	PARAM_SIZE, %ebp

	pushl	%ebx	FRAME_pushl()

L(strip_twos):

	incl	%ecx

	shrl	%eax

	jnc	L(strip_twos)

	leal	1(%eax,%eax), %ebx	C d without twos

	andl	$127, %eax		C d/2, 7 bits

ifdef(`PIC',`

	LEA(	binvert_limb_table, %edx)

	movzbl	(%eax,%edx), %eax		C inv 8 bits

',`

	movzbl	binvert_limb_table(%eax), %eax	C inv 8 bits

')

	leal	(%eax,%eax), %edx	C 2*inv

	movl	%ebx, PARAM_DIVISOR	C d without twos

	imull	%eax, %eax		C inv*inv

	imull	%ebx, %eax		C inv*inv*d

	subl	%eax, %edx		C inv = 2*inv - inv*inv*d

	leal	(%edx,%edx), %eax	C 2*inv

	imull	%edx, %edx		C inv*inv

	imull	%ebx, %edx		C inv*inv*d

	subl	%edx, %eax		C inv = 2*inv - inv*inv*d

	ASSERT(e,`	C expect d*inv == 1 mod 2^GMP_LIMB_BITS

	pushl	%eax	FRAME_pushl()

	imull	PARAM_DIVISOR, %eax

	cmpl	$1, %eax

	popl	%eax	FRAME_popl()')

	jmp	L(common)

EPILOGUE()

ASM_END()