.file "nearbyintf.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

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

// 10/19/00 Created

// 02/08/01 Corrected behavior for all rounding modes.

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

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

// 07/25/03 Improved performance

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

// API

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

// float nearbyintf(float x)

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

// general input registers:

// r14 - r21

rSignexp   = r14

rExp       = r15

rExpMask   = r16

rBigexp    = r17

rFpsr      = r19

rRcs0      = r20

rRcs0Mask  = r21

// floating-point registers:

// f8 - f10

fXInt      = f9

fNormX     = f10

// predicate registers used:

// p6 - p10

// Overview of operation

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

// float nearbyintf(float x)

// Return an integer value (represented as a float) that is x

// rounded to integer in current rounding mode

// Inexact is not set, otherwise result identical with rint.

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

// 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 .text

GLOBAL_LIBM_ENTRY(nearbyintf)

{ .mfi

      getf.exp         rSignexp  = f8        // Get signexp, recompute if unorm

      fclass.m         p7,p0 = f8, 0x0b      // Test x unorm

      addl             rBigexp = 0x10016, r0 // Set exponent at which is integer

}

{ .mfi

      nop.m            0

      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

      nop.m            0

      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.s.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| < 2^23

      cmp.ge           p7,p8 = rExp, rBigexp  // Is |x| >= 2^23?

}

;;

// We must correct result if |x| >= 2^23

{ .mfi

      nop.m            0

(p7)  fma.s.s0         f8 = fNormX, f1, f0    // If |x| >= 2^23, result x

      nop.i            0

}

;;

{ .mfi

      nop.m            0

(p8)  fmerge.s         f8 = fNormX, f8        // Make sign nearbyintf(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| < 2^23 we must test for other rounding modes

{ .mbb

(p8)  cmp.ne.unc       p10,p0 = rRcs0, r0     // Test for other rounding modes

(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| < 2^23

// 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_LIBM_END(nearbyintf)

libm_alias_float_other (nearbyint, nearbyint)