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.file "modff.s"
// Copyright (c) 2000, 2001, Intel Corporation
// All rights reserved.
//
// Contributed 2/2/2000 by John Harrison, Ted Kubaska, Bob Norin, Shane Story,
// and Ping Tak Peter Tang of the Computational Software Lab, Intel Corporation.
//
// WARRANTY DISCLAIMER
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL INTEL OR ITS
// CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
// EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
// PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
// OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY OR TORT (INCLUDING
// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
// Intel Corporation is the author of this code, and requests that all
// problem reports or change requests be submitted to it directly at
// http://developer.intel.com/opensource.
//
// History
//==============================================================
// 2/02/00: Initial version
// 4/04/00: 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.
//
// API
//==============================================================
// float modff(float x, float *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 0x10016
// -----------------------+-----------------+-------------
// SMALL | NORMAL | HUGE
// p11 --------------->|<----- p12 ----->| <-------------- p9
// p10 --------------------------------->|
// p13 --------------------------------------------------->|
//
#include "libm_support.h"
// 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
.align 32
.global modff#
.section .text
.proc modff#
.align 32
// 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
modff:
{ .mfi
getf.exp modf_signexp = f8
fnorm 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 = 0x10016, 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 L(MODF_DENORM) ;;
}
L(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.s 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.s 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) stfs [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) stfs [r33] = MODF_NORM_F8
(p7) fmerge.s f8 = MODF_NORM_F8, MODF_NORM_F8
nop.i 999 ;;
}
{ .mmi
(p9) stfs [r33] = MODF_INTEGER_PART
nop.m 999
nop.i 999 ;;
}
// For NORMAL compute fraction part
{ .mfi
(p11) stfs [r33] = MODF_INTEGER_PART
(p12) fms.s.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 p7,p0 = MODF_NORM_F8, MODF_INTEGER_PART
nop.i 999 ;;
}
{ .mfi
(p12) stfs [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 ;;
}
L(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 L(MODF_COMMON) ;;
}
.endp modff
ASM_SIZE_DIRECTIVE(modff)
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