.file "modf.s"

// Copyright (c) 2000 - 2003, Intel Corporation

// All rights reserved.

//

// Contributed 2000 by the Intel Numerics Group, Intel Corporation

//

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//

// History

//==============================================================

// 02/02/00 Initial version

// 04/04/00 Improved speed, corrected result for NaN input

// 12/22/00 Fixed so inexact flag is never set, and invalid is not set for

//            qnans nor for inputs larger than 2^63.

// 05/20/02 Cleaned up namespace and sf0 syntax

// 02/10/03 Reordered header: .section, .global, .proc, .align

//

// API

//==============================================================

// double modf(double x, double *iptr)

// break a floating point x number into fraction and an exponent

//

// input  floating point f8, address in r33

// output floating point f8 (x fraction), and *iptr (x integral part)

//

// OVERVIEW

//==============================================================

//

// NO FRACTIONAL PART: HUGE

// If

// for double-extended

// If the true exponent is greater than or equal 63

//      1003e ==> 1003e -ffff = 3f = 63(dec)

// for double

// If the true exponent is greater than or equal 52

//                10033 -ffff = 34 = 52(dec)

// for single

// If the true exponent is greater than or equal 23

//                10016 -ffff = 17 = 23(dec)

// then

// we are already an integer (p9 true)

// NO INTEGER PART:    SMALL

//     Is f8 exponent less than register bias (that is, is it

//     less than 1). If it is, get the right sign of

//     zero and store this in iptr.

// CALCULATION: NOT HUGE, NOT SMALL

// To get the integer part

// Take the floating-point  input and truncate

//   then convert  this integer to fp  Call it  MODF_INTEGER_PART

// Subtract  MODF_INTEGER_PART from MODF_NORM_F8 to get fraction part

// Then put fraction part in f8

//      put integer  part MODF_INTEGER_PART into *iptr

// Registers used

//==============================================================

// predicate registers used:

// p6 - p13

//                      0xFFFF           0x10033

// -----------------------+-----------------+-------------

//              SMALL     |      NORMAL     | HUGE

//    p11 --------------->|<----- p12 ----->| <-------------- p9

//    p10 --------------------------------->|

//    p13 --------------------------------------------------->|

//

// floating-point registers used:

MODF_NORM_F8               = f9

MODF_FRACTION_PART         = f10

MODF_INTEGER_PART          = f11

MODF_INT_INTEGER_PART      = f12

// general registers used

modf_signexp    = r14

modf_GR_no_frac = r15

modf_GR_FFFF    = r16

modf_17_ones    = r17

modf_exp        = r18

// r33 = iptr

.section .text

GLOBAL_LIBM_ENTRY(modf)

// Main path is p9, p11, p8 FALSE and p12 TRUE

// Assume input is normalized and get signexp

// Normalize input just in case

// Form exponent bias

{ .mfi

      getf.exp  modf_signexp = f8

      fnorm.s0          MODF_NORM_F8  = f8

      addl           modf_GR_FFFF  = 0xffff, r0

}

// Get integer part of input

// Form exponent mask

{ .mfi

      nop.m 999

      fcvt.fx.trunc.s1  MODF_INT_INTEGER_PART   = f8

      mov  modf_17_ones     = 0x1ffff ;;

}

// Is x nan or inf?

// qnan snan inf norm     unorm 0 -+

// 1    1    1   0        0     0 11 = 0xe3 NAN_INF

// Form biased exponent where input only has an integer part

{ .mfi

      nop.m 999

      fclass.m.unc p6,p13 = f8, 0xe3

      addl modf_GR_no_frac = 0x10033, r0 ;;

}

// Mask to get exponent

// Is x unnorm?

// qnan snan inf norm     unorm 0 -+

// 0    0    0   0        1     0 11 = 0x0b UNORM

// Set p13 to indicate calculation path, else p6 if nan or inf

{ .mfi

      and       modf_exp = modf_17_ones, modf_signexp

      fclass.m.unc p8,p0 = f8, 0x0b

      nop.i 999 ;;

}

// p11 <== SMALL, no integer part, fraction is everyting

// p9  <== HUGE,  no fraction part, integer is everything

// p12 <== NORMAL, fraction part and integer part

{ .mii

(p13) cmp.lt.unc p11,p10 = modf_exp, modf_GR_FFFF

      nop.i 999

      nop.i 999 ;;

}

// Is x inf? p6 if inf, p7 if nan

{ .mfb

(p10) cmp.ge.unc p9,p12  = modf_exp, modf_GR_no_frac

(p6)  fclass.m.unc p6,p7 = f8, 0x23

(p8)  br.cond.spnt MODF_DENORM ;;

}

MODF_COMMON:

// For HUGE set fraction to signed 0

{ .mfi

      nop.m 999

(p9)  fmerge.s f8 = f8,f0

      nop.i 999

}

// For HUGE set integer part to normalized input

{ .mfi

      nop.m 999

(p9)  fnorm.d.s0 MODF_INTEGER_PART = MODF_NORM_F8

      nop.i 999 ;;

}

// For SMALL set fraction to normalized input, integer part to signed 0

{ .mfi

      nop.m 999

(p11) fmerge.s MODF_INTEGER_PART = f8,f0

      nop.i 999

}

{ .mfi

      nop.m 999

(p11) fnorm.d.s0 f8 = MODF_NORM_F8

      nop.i 999 ;;

}

// For NORMAL float the integer part

{ .mfi

      nop.m 999

(p12) fcvt.xf    MODF_INTEGER_PART = MODF_INT_INTEGER_PART

      nop.i 999 ;;

}

// If x inf set integer part to INF, fraction to signed 0

{ .mfi

(p6)  stfd [r33] = MODF_NORM_F8

(p6)  fmerge.s  f8 = f8,f0

      nop.i 999 ;;

}

// If x nan set integer and fraction parts to NaN (quietized)

{ .mfi

(p7)  stfd [r33] = MODF_NORM_F8

(p7)  fmerge.s  f8 = MODF_NORM_F8, MODF_NORM_F8

      nop.i 999 ;;

}

{ .mmi

(p9)  stfd [r33] = MODF_INTEGER_PART

      nop.m 999

      nop.i 999 ;;

}

// For NORMAL compute fraction part

{ .mfi

(p11) stfd [r33] = MODF_INTEGER_PART

(p12) fms.d.s0   f8 = MODF_NORM_F8,f1, MODF_INTEGER_PART

      nop.i 999 ;;

}

// For NORMAL test if fraction part is zero; if so append correct sign

{ .mfi

      nop.m 999

(p12) fcmp.eq.unc.s0 p7,p0 = MODF_NORM_F8, MODF_INTEGER_PART

      nop.i 999 ;;

}

{ .mfi

(p12) stfd [r33] = MODF_INTEGER_PART

      nop.f 999

      nop.i 999 ;;

}

// For NORMAL if fraction part is zero append sign of input

{ .mfb

      nop.m 999

(p7)  fmerge.s f8 = MODF_NORM_F8, f0

      br.ret.sptk    b0 ;;

}

MODF_DENORM:

// If x unorm get signexp from normalized input

// If x unorm get integer part from normalized input

{ .mfi

      getf.exp  modf_signexp = MODF_NORM_F8

      fcvt.fx.trunc.s1  MODF_INT_INTEGER_PART   = MODF_NORM_F8

      nop.i 999 ;;

}

// If x unorm mask to get exponent

{ .mmi

      and       modf_exp = modf_17_ones, modf_signexp ;;

      cmp.lt.unc p11,p10 = modf_exp, modf_GR_FFFF

      nop.i 999 ;;

}

{ .mfb

(p10) cmp.ge.unc p9,p12  = modf_exp, modf_GR_no_frac

      nop.f 999

      br.cond.spnt MODF_COMMON ;;

}

GLOBAL_LIBM_END(modf)

libm_alias_double_other (modf, modf)