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/*
 * Copyright (C) 1999-2000 Hewlett-Packard Co
 * Copyright (C) 1999-2000 David Mosberger-Tang <davidm@hpl.hp.com>
 *
 * 64-bit integer division.
 *
 * This code is based on the application note entitled "Divide, Square Root
 * and Remainder Algorithms for the IA-64 Architecture".  This document
 * is available as Intel document number 248725-002 or via the web at
 * http://developer.intel.com/software/opensource/numerics/
 *
 * For more details on the theory behind these algorithms, see "IA-64
 * and Elementary Functions" by Peter Markstein; HP Professional Books
 * (http://www.hp.com/go/retailbooks/)
 */

#include <asm/asmmacro.h>

#ifdef MODULO
# define OP     mod
#else
# define OP     div
#endif

#ifdef UNSIGNED
# define SGN    u
# define INT_TO_FP(a,b) fcvt.xuf.s1 a=b
# define FP_TO_INT(a,b) fcvt.fxu.trunc.s1 a=b
#else
# define SGN
# define INT_TO_FP(a,b) fcvt.xf a=b
# define FP_TO_INT(a,b) fcvt.fx.trunc.s1 a=b
#endif

#define PASTE1(a,b)     a##b
#define PASTE(a,b)      PASTE1(a,b)
#define NAME            PASTE(PASTE(__,SGN),PASTE(OP,di3))

GLOBAL_ENTRY(NAME)
        .regstk 2,0,0,0
        // Transfer inputs to FP registers.
        setf.sig f8 = in0
        setf.sig f9 = in1
        ;;
        // Convert the inputs to FP, to avoid FP software-assist faults.
        INT_TO_FP(f8, f8)
        INT_TO_FP(f9, f9)
        ;;
        frcpa.s1 f11, p6 = f8, f9       // y0 = frcpa(b)
        ;;
(p6)    fmpy.s1 f7 = f8, f11            // q0 = a*y0
(p6)    fnma.s1 f6 = f9, f11, f1        // e0 = -b*y0 + 1
        ;;
(p6)    fma.s1 f10 = f7, f6, f7         // q1 = q0*e0 + q0
(p6)    fmpy.s1 f7 = f6, f6             // e1 = e0*e0
        ;;
#ifdef MODULO
        sub in1 = r0, in1               // in1 = -b
#endif
(p6)    fma.s1 f10 = f10, f7, f10       // q2 = q1*e1 + q1
(p6)    fma.s1 f6 = f11, f6, f11        // y1 = y0*e0 + y0
        ;;
(p6)    fma.s1 f6 = f6, f7, f6          // y2 = y1*e1 + y1
(p6)    fnma.s1 f7 = f9, f10, f8        // r = -b*q2 + a
        ;;
#ifdef MODULO
        setf.sig f8 = in0               // f8 = a
        setf.sig f9 = in1               // f9 = -b
#endif
(p6)    fma.s1 f11 = f7, f6, f10        // q3 = r*y2 + q2
        ;;
        FP_TO_INT(f11, f11)             // q = trunc(q3)
        ;;
#ifdef MODULO
        xma.l f11 = f11, f9, f8         // r = q*(-b) + a
        ;;
#endif
        getf.sig r8 = f11               // transfer result to result register
        br.ret.sptk.many rp
END(NAME)