1/* 2 * Copyright (C) 2000 Hewlett-Packard Co 3 * Copyright (C) 2000 David Mosberger-Tang <davidm@hpl.hp.com> 4 * 5 * 32-bit integer division. 6 * 7 * This code is based on the application note entitled "Divide, Square Root 8 * and Remainder Algorithms for the IA-64 Architecture". This document 9 * is available as Intel document number 248725-002 or via the web at 10 * http://developer.intel.com/software/opensource/numerics/ 11 * 12 * For more details on the theory behind these algorithms, see "IA-64 13 * and Elementary Functions" by Peter Markstein; HP Professional Books 14 * (http://www.goodreads.com/book/show/2019887.Ia_64_and_Elementary_Functions) 15 */ 16 17#include <asm/asmmacro.h> 18#include <asm/export.h> 19 20#ifdef MODULO 21# define OP mod 22#else 23# define OP div 24#endif 25 26#ifdef UNSIGNED 27# define SGN u 28# define EXTEND zxt4 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 EXTEND sxt4 34# define INT_TO_FP(a,b) fcvt.xf a=b 35# define FP_TO_INT(a,b) fcvt.fx.trunc.s1 a=b 36#endif 37 38#define PASTE1(a,b) a##b 39#define PASTE(a,b) PASTE1(a,b) 40#define NAME PASTE(PASTE(__,SGN),PASTE(OP,si3)) 41 42GLOBAL_ENTRY(NAME) 43 .regstk 2,0,0,0 44 // Transfer inputs to FP registers. 45 mov r2 = 0xffdd // r2 = -34 + 65535 (fp reg format bias) 46 EXTEND in0 = in0 // in0 = a 47 EXTEND in1 = in1 // in1 = b 48 ;; 49 setf.sig f8 = in0 50 setf.sig f9 = in1 51#ifdef MODULO 52 sub in1 = r0, in1 // in1 = -b 53#endif 54 ;; 55 // Convert the inputs to FP, to avoid FP software-assist faults. 56 INT_TO_FP(f8, f8) 57 INT_TO_FP(f9, f9) 58 ;; 59 setf.exp f7 = r2 // f7 = 2^-34 60 frcpa.s1 f6, p6 = f8, f9 // y0 = frcpa(b) 61 ;; 62(p6) fmpy.s1 f8 = f8, f6 // q0 = a*y0 63(p6) fnma.s1 f6 = f9, f6, f1 // e0 = -b*y0 + 1 64 ;; 65#ifdef MODULO 66 setf.sig f9 = in1 // f9 = -b 67#endif 68(p6) fma.s1 f8 = f6, f8, f8 // q1 = e0*q0 + q0 69(p6) fma.s1 f6 = f6, f6, f7 // e1 = e0*e0 + 2^-34 70 ;; 71#ifdef MODULO 72 setf.sig f7 = in0 73#endif 74(p6) fma.s1 f6 = f6, f8, f8 // q2 = e1*q1 + q1 75 ;; 76 FP_TO_INT(f6, f6) // q = trunc(q2) 77 ;; 78#ifdef MODULO 79 xma.l f6 = f6, f9, f7 // r = q*(-b) + a 80 ;; 81#endif 82 getf.sig r8 = f6 // transfer result to result register 83 br.ret.sptk.many rp 84END(NAME) 85EXPORT_SYMBOL(NAME) 86