.file "roundf.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//==============================================================// 10/25/00 Initial version// 06/14/01 Changed cmp to an equivalent form// 05/20/02 Cleaned up namespace and sf0 syntax// 01/20/03 Improved performance and reduced code size// 04/18/03 Eliminate possible WAW dependency warning// 09/03/03 Improved performance//==============================================================// API//==============================================================// float roundf(float x)//==============================================================// general input registers:// r14 - r18rSignexp   = r14rExp       = r15rExpMask   = r16rBigexp    = r17rExpHalf   = r18// floating-point registers:// f8 - f13fXtruncInt = f9fNormX     = f10fHalf      = f11fInc       = f12fRem       = f13// predicate registers used:// p6 - p10// Overview of operation//==============================================================// float roundf(float x)// Return an integer value (represented as a float) that is x// rounded to nearest integer, halfway cases rounded away from// zero.//  if x>0   result = trunc(x+0.5)//  if x<0   result = trunc(x-0.5)////==============================================================// 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_LIBM_ENTRY(roundf){ .mfi      getf.exp         rSignexp  = f8        // Get signexp, recompute if unorm      fcvt.fx.trunc.s1 fXtruncInt  = f8      // Convert to int in significand      addl             rBigexp = 0x10016, r0 // Set exponent at which is integer}{ .mfi      mov              rExpHalf    = 0x0FFFE // Form sign and exponent of 0.5      fnorm.s1         fNormX  = f8          // Normalize input      mov              rExpMask    = 0x1FFFF // Form exponent mask};;{ .mfi      setf.exp         fHalf = rExpHalf      // Form 0.5      fclass.m         p7,p0 = f8, 0x0b      // Test x unorm      nop.i            0};;{ .mfb      nop.m            0      fclass.m         p6,p0 = f8, 0x1e3     // Test x natval, nan, inf(p7)  br.cond.spnt     ROUND_UNORM           // Branch if x unorm};;ROUND_COMMON:// Return here from ROUND_UNORM{ .mfb      nop.m            0      fcmp.lt.s1       p8,p9 = f8, f0        // Test if x < 0(p6)  br.cond.spnt     ROUND_SPECIAL         // Exit if x natval, nan, inf};;{ .mfi      nop.m            0      fcvt.xf          f8 = fXtruncInt        // Pre-Result if 0.5 <= |x| < 2^23      nop.i            0};;{ .mfi      and              rExp = rSignexp, rExpMask // Get biased exponent      fmerge.s         fInc = fNormX, f1      // Form increment if |rem| >= 0.5      nop.i            0};;{ .mmi      cmp.lt           p6,p0 = rExp, rExpHalf // Is |x| < 0.5?      cmp.ge           p7,p0 = rExp, rBigexp  // Is |x| >= 2^23?      cmp.lt           p10,p0 = rExp, rExpHalf // Is |x| < 0.5? };;// We must correct result if |x| < 0.5, or |x| >= 2^23.pred.rel "mutex",p6,p7{ .mfi      nop.m            0(p6)  fmerge.s         f8 = fNormX, f0        // If |x| < 0.5, result sgn(x)*0      nop.i            0}{ .mfb(p7)  cmp.eq           p10,p0 = r0, r0        // Also turn on p10 if |x| >= 2^23(p7)  fma.s.s0         f8 = fNormX, f1, f0    // If |x| >= 2^23, result x(p10) br.ret.spnt      b0                     // Exit |x| < 0.5 or |x| >= 2^23};;// Here if 0.5 <= |x| < 2^23{ .mfi      nop.m            0(p9)  fms.s1           fRem = fNormX, f1, f8  // Get remainder = x - trunc(x)      nop.i            0}{ .mfi      nop.m            0(p8)  fms.s1           fRem = f8, f1, fNormX  // Get remainder = trunc(x) - x      nop.i            0};;{ .mfi      nop.m            0      fcmp.ge.s1       p9,p0 = fRem, fHalf    // Test |rem| >= 0.5      nop.i            0};;// If x < 0 and remainder <= -0.5, then subtract 1 from result// If x > 0 and remainder >= +0.5, then add 1 to result{ .mfb      nop.m            0(p9)  fma.s.s0         f8 = f8, f1, fInc      br.ret.sptk      b0};;ROUND_SPECIAL:// Here if x natval, nan, inf{ .mfb      nop.m            0      fma.s.s0         f8 = f8, f1, f0      br.ret.sptk      b0};;ROUND_UNORM:// Here if x unorm{ .mfi      getf.exp         rSignexp  = fNormX     // Get signexp, recompute if unorm      fcmp.eq.s0       p7,p0 = f8, f0         // Dummy op to set denormal flag      nop.i            0}{ .mfb      nop.m            0      fcvt.fx.trunc.s1 fXtruncInt  = fNormX   // Convert to int in significand      br.cond.sptk     ROUND_COMMON           // Return to main path};;GLOBAL_LIBM_END(roundf)