1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Copyright (C) 1999-2000 Hewlett-Packard Co
4 * Copyright (C) 1999-2000 David Mosberger-Tang <davidm@hpl.hp.com>
5 *
6 * 64-bit integer division.
7 *
8 * This code is based on the application note entitled "Divide, Square Root
9 * and Remainder Algorithms for the IA-64 Architecture".  This document
10 * is available as Intel document number 248725-002 or via the web at
11 * http://developer.intel.com/software/opensource/numerics/
12 *
13 * For more details on the theory behind these algorithms, see "IA-64
14 * and Elementary Functions" by Peter Markstein; HP Professional Books
15 * (http://www.goodreads.com/book/show/2019887.Ia_64_and_Elementary_Functions)
16 */
17
18#include <linux/export.h>
19#include <asm/asmmacro.h>
20
21#ifdef MODULO
22# define OP	mod
23#else
24# define OP	div
25#endif
26
27#ifdef UNSIGNED
28# define SGN	u
29# define INT_TO_FP(a,b)	fcvt.xuf.s1 a=b
30# define FP_TO_INT(a,b)	fcvt.fxu.trunc.s1 a=b
31#else
32# define SGN
33# define INT_TO_FP(a,b)	fcvt.xf a=b
34# define FP_TO_INT(a,b)	fcvt.fx.trunc.s1 a=b
35#endif
36
37#define PASTE1(a,b)	a##b
38#define PASTE(a,b)	PASTE1(a,b)
39#define NAME		PASTE(PASTE(__,SGN),PASTE(OP,di3))
40
41GLOBAL_ENTRY(NAME)
42	.regstk 2,0,0,0
43	// Transfer inputs to FP registers.
44	setf.sig f8 = in0
45	setf.sig f9 = in1
46	;;
47	// Convert the inputs to FP, to avoid FP software-assist faults.
48	INT_TO_FP(f8, f8)
49	INT_TO_FP(f9, f9)
50	;;
51	frcpa.s1 f11, p6 = f8, f9	// y0 = frcpa(b)
52	;;
53(p6)	fmpy.s1 f7 = f8, f11		// q0 = a*y0
54(p6)	fnma.s1 f6 = f9, f11, f1	// e0 = -b*y0 + 1
55	;;
56(p6)	fma.s1 f10 = f7, f6, f7		// q1 = q0*e0 + q0
57(p6)	fmpy.s1 f7 = f6, f6		// e1 = e0*e0
58	;;
59#ifdef MODULO
60	sub in1 = r0, in1		// in1 = -b
61#endif
62(p6)	fma.s1 f10 = f10, f7, f10	// q2 = q1*e1 + q1
63(p6)	fma.s1 f6 = f11, f6, f11	// y1 = y0*e0 + y0
64	;;
65(p6)	fma.s1 f6 = f6, f7, f6		// y2 = y1*e1 + y1
66(p6)	fnma.s1 f7 = f9, f10, f8	// r = -b*q2 + a
67	;;
68#ifdef MODULO
69	setf.sig f8 = in0		// f8 = a
70	setf.sig f9 = in1		// f9 = -b
71#endif
72(p6)	fma.s1 f11 = f7, f6, f10	// q3 = r*y2 + q2
73	;;
74	FP_TO_INT(f11, f11)		// q = trunc(q3)
75	;;
76#ifdef MODULO
77	xma.l f11 = f11, f9, f8		// r = q*(-b) + a
78	;;
79#endif
80	getf.sig r8 = f11		// transfer result to result register
81	br.ret.sptk.many rp
82END(NAME)
83EXPORT_SYMBOL(NAME)
84