81 lines
		
	
	
	
		
			2 KiB
			
		
	
	
	
		
			ArmAsm
		
	
	
	
	
	
		
		
			
		
	
	
			81 lines
		
	
	
	
		
			2 KiB
			
		
	
	
	
		
			ArmAsm
		
	
	
	
	
	
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								/*
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								 * Copyright (C) 1999-2000 Hewlett-Packard Co
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								 * Copyright (C) 1999-2000 David Mosberger-Tang <davidm@hpl.hp.com>
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								 *
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								 * 64-bit integer division.
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								 *
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								 * This code is based on the application note entitled "Divide, Square Root
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								 * and Remainder Algorithms for the IA-64 Architecture".  This document
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								 * is available as Intel document number 248725-002 or via the web at
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								 * http://developer.intel.com/software/opensource/numerics/
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								 *
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								 * For more details on the theory behind these algorithms, see "IA-64
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								 * and Elementary Functions" by Peter Markstein; HP Professional Books
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								 * (http://www.hp.com/go/retailbooks/)
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								 */
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								#include <asm/asmmacro.h>
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								#ifdef MODULO
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								# define OP	mod
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								#else
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								# define OP	div
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								#endif
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								#ifdef UNSIGNED
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								# define SGN	u
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								# define INT_TO_FP(a,b)	fcvt.xuf.s1 a=b
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								# define FP_TO_INT(a,b)	fcvt.fxu.trunc.s1 a=b
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								#else
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								# define SGN
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								# define INT_TO_FP(a,b)	fcvt.xf a=b
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								# define FP_TO_INT(a,b)	fcvt.fx.trunc.s1 a=b
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								#endif
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								#define PASTE1(a,b)	a##b
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								#define PASTE(a,b)	PASTE1(a,b)
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								#define NAME		PASTE(PASTE(__,SGN),PASTE(OP,di3))
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								GLOBAL_ENTRY(NAME)
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									.regstk 2,0,0,0
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									// Transfer inputs to FP registers.
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									setf.sig f8 = in0
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									setf.sig f9 = in1
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									;;
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									// Convert the inputs to FP, to avoid FP software-assist faults.
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									INT_TO_FP(f8, f8)
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									INT_TO_FP(f9, f9)
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									;;
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									frcpa.s1 f11, p6 = f8, f9	// y0 = frcpa(b)
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									;;
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								(p6)	fmpy.s1 f7 = f8, f11		// q0 = a*y0
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								(p6)	fnma.s1 f6 = f9, f11, f1	// e0 = -b*y0 + 1
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									;;
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								(p6)	fma.s1 f10 = f7, f6, f7		// q1 = q0*e0 + q0
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								(p6)	fmpy.s1 f7 = f6, f6		// e1 = e0*e0
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									;;
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								#ifdef MODULO
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									sub in1 = r0, in1		// in1 = -b
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								#endif
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								(p6)	fma.s1 f10 = f10, f7, f10	// q2 = q1*e1 + q1
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								(p6)	fma.s1 f6 = f11, f6, f11	// y1 = y0*e0 + y0
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									;;
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								(p6)	fma.s1 f6 = f6, f7, f6		// y2 = y1*e1 + y1
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								(p6)	fnma.s1 f7 = f9, f10, f8	// r = -b*q2 + a
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									;;
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								#ifdef MODULO
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									setf.sig f8 = in0		// f8 = a
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									setf.sig f9 = in1		// f9 = -b
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								#endif
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								(p6)	fma.s1 f11 = f7, f6, f10	// q3 = r*y2 + q2
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									;;
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									FP_TO_INT(f11, f11)		// q = trunc(q3)
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									;;
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								#ifdef MODULO
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									xma.l f11 = f11, f9, f8		// r = q*(-b) + a
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									;;
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								#endif
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									getf.sig r8 = f11		// transfer result to result register
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									br.ret.sptk.many rp
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								END(NAME)
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