1/* SPDX-License-Identifier: GPL-2.0 */ 2/* 3 * Copyright (C) 2000 Hewlett-Packard Co 4 * Copyright (C) 2000 David Mosberger-Tang <davidm@hpl.hp.com> 5 * 6 * 32-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 EXTEND zxt4 30# define INT_TO_FP(a,b) fcvt.xuf.s1 a=b 31# define FP_TO_INT(a,b) fcvt.fxu.trunc.s1 a=b 32#else 33# define SGN 34# define EXTEND sxt4 35# define INT_TO_FP(a,b) fcvt.xf a=b 36# define FP_TO_INT(a,b) fcvt.fx.trunc.s1 a=b 37#endif 38 39#define PASTE1(a,b) a##b 40#define PASTE(a,b) PASTE1(a,b) 41#define NAME PASTE(PASTE(__,SGN),PASTE(OP,si3)) 42 43GLOBAL_ENTRY(NAME) 44 .regstk 2,0,0,0 45 // Transfer inputs to FP registers. 46 mov r2 = 0xffdd // r2 = -34 + 65535 (fp reg format bias) 47 EXTEND in0 = in0 // in0 = a 48 EXTEND in1 = in1 // in1 = b 49 ;; 50 setf.sig f8 = in0 51 setf.sig f9 = in1 52#ifdef MODULO 53 sub in1 = r0, in1 // in1 = -b 54#endif 55 ;; 56 // Convert the inputs to FP, to avoid FP software-assist faults. 57 INT_TO_FP(f8, f8) 58 INT_TO_FP(f9, f9) 59 ;; 60 setf.exp f7 = r2 // f7 = 2^-34 61 frcpa.s1 f6, p6 = f8, f9 // y0 = frcpa(b) 62 ;; 63(p6) fmpy.s1 f8 = f8, f6 // q0 = a*y0 64(p6) fnma.s1 f6 = f9, f6, f1 // e0 = -b*y0 + 1 65 ;; 66#ifdef MODULO 67 setf.sig f9 = in1 // f9 = -b 68#endif 69(p6) fma.s1 f8 = f6, f8, f8 // q1 = e0*q0 + q0 70(p6) fma.s1 f6 = f6, f6, f7 // e1 = e0*e0 + 2^-34 71 ;; 72#ifdef MODULO 73 setf.sig f7 = in0 74#endif 75(p6) fma.s1 f6 = f6, f8, f8 // q2 = e1*q1 + q1 76 ;; 77 FP_TO_INT(f6, f6) // q = trunc(q2) 78 ;; 79#ifdef MODULO 80 xma.l f6 = f6, f9, f7 // r = q*(-b) + a 81 ;; 82#endif 83 getf.sig r8 = f6 // transfer result to result register 84 br.ret.sptk.many rp 85END(NAME) 86EXPORT_SYMBOL(NAME) 87