.file "rint.s"// Copyright (c) 2000 - 2003, Intel Corporation// All rights reserved.//// Contributed 2000 by the Intel Numerics Group, Intel Corporation//// Redistribution and use in source and binary forms, with or without// modification, are permitted provided that the following conditions are// met://// * Redistributions of source code must retain the above copyright// notice, this list of conditions and the following disclaimer.//// * Redistributions in binary form must reproduce the above copyright// notice, this list of conditions and the following disclaimer in the// documentation and/or other materials provided with the distribution.//// * The name of Intel Corporation may not be used to endorse or promote// products derived from this software without specific prior written// permission.// 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://www.intel.com/software/products/opensource/libraries/num.htm.//// History//==============================================================// 02/02/00 Initial version// 02/08/01 Corrected behavior for all rounding modes.// 05/20/02 Cleaned up namespace and sf0 syntax// 01/20/03 Improved performance//==============================================================// API//==============================================================// double rint(double x)//==============================================================// general input registers:// r14 - r21rSignexp   = r14rExp       = r15rExpMask   = r16rBigexp    = r17rM1        = r18rFpsr      = r19rRcs0      = r20rRcs0Mask  = r21// floating-point registers:// f8 - f11fXInt      = f9fNormX     = f10fTmp       = f11// predicate registers used:// p6 - p10// Overview of operation//==============================================================// double rint(double x)// Return an integer value (represented as a double) that is x// rounded to integer in current rounding mode// Inexact is set if x != rint(x)//==============================================================// double_extended// if the exponent is > 1003e => 3F(true) = 63(decimal)// we have a significand of 64 bits 1.63-bits.// If we multiply by 2^63, we no longer have a fractional part// So input is an integer value already.// double// if the exponent is >= 10033 => 34(true) = 52(decimal)// 34 + 3ff = 433// we have a significand of 53 bits 1.52-bits. (implicit 1)// If we multiply by 2^52, we no longer have a fractional part// So input is an integer value already.// single// if the exponent is > 10016 => 17(true) = 23(decimal)// we have a significand of 24 bits 1.23-bits. (implicit 1)// If we multiply by 2^23, we no longer have a fractional part// So input is an integer value already..section .textGLOBAL_IEEE754_ENTRY(rint){ .mfi      getf.exp         rSignexp  = f8        // Get signexp, recompute if unorm      fclass.m         p7,p0 = f8, 0x0b      // Test x unorm      addl             rBigexp = 0x10033, r0 // Set exponent at which is integer}{ .mfi      mov              rM1 = -1              // Set all ones      fcvt.fx.s1       fXInt  = f8           // Convert to int in significand      mov              rExpMask    = 0x1FFFF // Form exponent mask};;{ .mfi      mov              rFpsr = ar40          // Read fpsr -- check rc.s0      fclass.m         p6,p0 = f8, 0x1e3     // Test x natval, nan, inf      nop.i            0}{ .mfb      setf.sig         fTmp = rM1            // Make const for setting inexact      fnorm.s1         fNormX  = f8          // Normalize input(p7)  br.cond.spnt     RINT_UNORM            // Branch if x unorm};;RINT_COMMON:// Return here from RINT_UNORM{ .mfb      and              rExp = rSignexp, rExpMask // Get biased exponent(p6)  fma.d.s0         f8 = f8, f1, f0       // Result if x natval, nan, inf(p6)  br.ret.spnt      b0                    // Exit if x natval, nan, inf};;{ .mfi      mov              rRcs0Mask = 0x0c00     // Mask for rc.s0      fcvt.xf          f8 = fXInt             // Result assume |x| < 2^52      cmp.ge           p7,p8 = rExp, rBigexp  // Is |x| >= 2^52?};;// We must correct result if |x| >= 2^52{ .mfi      nop.m            0(p7)  fma.d.s0         f8 = fNormX, f1, f0    // If |x| >= 2^52, result x      nop.i            0};;{ .mfi      nop.m            0      fcmp.eq.unc.s1   p0, p9 = f8, fNormX    // Is result = x ?      nop.i            0}{ .mfi      nop.m            0(p8)  fmerge.s         f8 = fNormX, f8        // Make sure sign rint(x) = sign x      nop.i            0};;{ .mfi(p8)  and              rRcs0 = rFpsr, rRcs0Mask // Get rounding mode for sf0      nop.f            0      nop.i            0};;// If |x| < 2^52 we must test for other rounding modes{ .mfi(p8)  cmp.ne.unc       p10,p0 = rRcs0, r0     // Test for other rounding modes(p9)  fmpy.s0          fTmp = fTmp, fTmp      // Dummy to set inexact      nop.i            0}{ .mbb      nop.m            0(p10) br.cond.spnt     RINT_NOT_ROUND_NEAREST // Branch if not round nearest      br.ret.sptk      b0                     // Exit main path if round nearest};;RINT_UNORM:// Here if x unorm{ .mfb      getf.exp         rSignexp  = fNormX     // Get signexp, recompute if unorm      fcmp.eq.s0       p7,p0 = f8, f0         // Dummy op to set denormal flag      br.cond.sptk     RINT_COMMON            // Return to main path};;RINT_NOT_ROUND_NEAREST:// Here if not round to nearest, and |x| < 2^52// Set rounding mode of s2 to that of s0, and repeat the conversion using s2{ .mfi      nop.m            0      fsetc.s2         0x7f, 0x40      nop.i            0};;{ .mfi      nop.m            0      fcvt.fx.s2       fXInt  = fNormX        // Convert to int in significand      nop.i            0};;{ .mfi      nop.m            0      fcvt.xf          f8 = fXInt             // Expected result      nop.i            0};;// Be sure sign of result = sign of input.  Fixes cases where result is 0.{ .mfb      nop.m            0      fmerge.s         f8 = fNormX, f8      br.ret.sptk      b0                     // Exit main path};;GLOBAL_IEEE754_END(rint)