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.hp.com/go/retailbooks/) 15 */ 16 17#include <asm/asmmacro.h> 18 19#ifdef MODULO 20# define OP mod 21#else 22# define OP div 23#endif 24 25#ifdef UNSIGNED 26# define SGN u 27# define EXTEND zxt4 28# define INT_TO_FP(a,b) fcvt.xuf.s1 a=b 29# define FP_TO_INT(a,b) fcvt.fxu.trunc.s1 a=b 30#else 31# define SGN 32# define EXTEND sxt4 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,si3)) 40 41GLOBAL_ENTRY(NAME) 42 .regstk 2,0,0,0 43 // Transfer inputs to FP registers. 44 mov r2 = 0xffdd // r2 = -34 + 65535 (fp reg format bias) 45 EXTEND in0 = in0 // in0 = a 46 EXTEND in1 = in1 // in1 = b 47 ;; 48 setf.sig f8 = in0 49 setf.sig f9 = in1 50#ifdef MODULO 51 sub in1 = r0, in1 // in1 = -b 52#endif 53 ;; 54 // Convert the inputs to FP, to avoid FP software-assist faults. 55 INT_TO_FP(f8, f8) 56 INT_TO_FP(f9, f9) 57 ;; 58 setf.exp f7 = r2 // f7 = 2^-34 59 frcpa.s1 f6, p6 = f8, f9 // y0 = frcpa(b) 60 ;; 61(p6) fmpy.s1 f8 = f8, f6 // q0 = a*y0 62(p6) fnma.s1 f6 = f9, f6, f1 // e0 = -b*y0 + 1 63 ;; 64#ifdef MODULO 65 setf.sig f9 = in1 // f9 = -b 66#endif 67(p6) fma.s1 f8 = f6, f8, f8 // q1 = e0*q0 + q0 68(p6) fma.s1 f6 = f6, f6, f7 // e1 = e0*e0 + 2^-34 69 ;; 70#ifdef MODULO 71 setf.sig f7 = in0 72#endif 73(p6) fma.s1 f6 = f6, f8, f8 // q2 = e1*q1 + q1 74 ;; 75 FP_TO_INT(f6, f6) // q = trunc(q2) 76 ;; 77#ifdef MODULO 78 xma.l f6 = f6, f9, f7 // r = q*(-b) + a 79 ;; 80#endif 81 getf.sig r8 = f6 // transfer result to result register 82 br.ret.sptk.many rp 83END(NAME) 84