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.file "modff.s"
// Copyright (c) 2000, 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//// 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 63// 1003e ==> 1003e -ffff = 3f = 63(dec)// for double// If the true exponent is greater than 52// 10033 -ffff = 34 = 52(dec)// for single// If the true exponent is greater than 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 --------------------------------------------------->|//
// floating-point registers used: MODF_NORM_F8 = f9MODF_FRACTION_PART = f10MODF_INTEGER_PART = f11MODF_INT_INTEGER_PART = f12
// general registers used modf_signexp = r14modf_GR_10016 = r15modf_GR_FFFF = r16modf_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(p0) getf.exp modf_signexp = f8(p0) fnorm MODF_NORM_F8 = f8(p0) addl modf_GR_FFFF = 0xffff, r0}// Get integer part of input// Form exponent mask{ .mfi nop.m 999(p0) fcvt.fx.trunc.s1 MODF_INT_INTEGER_PART = f8(p0) mov modf_17_ones = 0x1ffff ;;
}
// Is x unnorm?// qnan snan inf norm unorm 0 -+// 0 0 0 0 1 0 11 = 0x0b UNORM// Form biased exponent where input only has an integer part{ .mfi nop.m 999(p0) fclass.m.unc p8,p0 = f8, 0x0b(p0) addl modf_GR_10016 = 0x10016, r0 ;;
}
// Mask to get exponent// Is x nan or inf?// qnan snan inf norm unorm 0 -+// 1 1 1 0 0 0 11 = 0xe3 NAN_INF// Set p13 to indicate calculation path, else p6 if nan or inf { .mfi(p0) and modf_exp = modf_17_ones, modf_signexp (p0) fclass.m.unc p6,p13 = f8, 0xe3 nop.i 999 ;;
}
// If x unorm get signexp from normalized input// If x unorm get integer part from normalized input{ .mfi(p8) getf.exp modf_signexp = MODF_NORM_F8(p8) fcvt.fx.trunc MODF_INT_INTEGER_PART = MODF_NORM_F8 nop.i 999 ;;
}
// If x unorm mask to get exponent// Is x inf? p6 if inf, p7 if nan{ .mfi(p8) and modf_exp = modf_17_ones, modf_signexp(p6) fclass.m.unc p6,p7 = f8, 0x23 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 ;;
}
// For SMALL set fraction to normalized input, integer part to signed 0{ .mfi(p10) cmp.gt.unc p9,p12 = modf_exp, modf_GR_10016(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 HUGE set fraction to signed 0{ .mfi nop.m 999(p9) fmerge.s f8 = f8,f0 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}// For HUGE set integer part to normalized input{ .mfi nop.m 999(p9) fnorm.s MODF_INTEGER_PART = MODF_NORM_F8 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 ;;
}
// For NORMAL compute fraction part{ .mfi nop.m 999(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 p12,p0 = MODF_NORM_F8, MODF_INTEGER_PART nop.i 999 ;;
}
// For NORMAL if fraction part is zero append sign of input{ .mfb(p13) stfs [r33] = MODF_INTEGER_PART(p12) fmerge.s f8 = MODF_NORM_F8, f8(p0) br.ret.sptk b0 ;;
}
.endp modff
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