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.file "rint.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.
//
// 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://developer.intel.com/opensource.
//
// History
//==============================================================
// 2/02/00: Initial version
// 2/08/01 Corrected behavior for all rounding modes.
//
// API
//==============================================================
// double rint(double x)
#include "libm_support.h"
//
// general registers used:
//
rint_GR_FFFF = r14
rint_GR_signexp = r15
rint_GR_exponent = r16
rint_GR_17ones = r17
rint_GR_10033 = r18
rint_GR_fpsr = r19
rint_GR_rcs0 = r20
rint_GR_rcs0_mask = r21
// predicate registers used:
// p6-11
// floating-point registers used:
RINT_NORM_f8 = f9
RINT_FFFF = f10
RINT_INEXACT = f11
RINT_FLOAT_INT_f8 = f12
RINT_INT_f8 = f13
// 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)
// *******************************************************************************
// Set denormal flag for denormal input and
// and take denormal fault if necessary.
// Is the input an integer value already?
// 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 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.
// If x is NAN, ZERO, or INFINITY, then return
// qnan snan inf norm unorm 0 -+
// 1 1 1 0 0 1 11 0xe7
.align 32
.global rint#
.section .text
.proc rint#
.align 32
rint:
#ifdef _LIBC
.global __rint
.type __rint,@function
__rint:
#endif
{ .mfi
mov rint_GR_fpsr = ar40 // Read the fpsr--need to check rc.s0
fcvt.fx.s1 RINT_INT_f8 = f8
addl rint_GR_10033 = 0x10033, r0
}
{ .mfi
mov rint_GR_FFFF = -1
fnorm.s1 RINT_NORM_f8 = f8
mov rint_GR_17ones = 0x1FFFF
;;
}
{ .mfi
setf.sig RINT_FFFF = rint_GR_FFFF
fclass.m.unc p6,p0 = f8, 0xe7
mov rint_GR_rcs0_mask = 0x0c00
;;
}
{ .mfb
nop.m 999
(p6) fnorm.d f8 = f8
(p6) br.ret.spnt b0 // Exit if x nan, inf, zero
;;
}
{ .mfi
nop.m 999
fcvt.xf RINT_FLOAT_INT_f8 = RINT_INT_f8
nop.i 999
;;
}
{ .mfi
getf.exp rint_GR_signexp = RINT_NORM_f8
fcmp.eq.s0 p8,p0 = f8,f0 // Dummy op to set denormal
nop.i 999
;;
}
{ .mii
nop.m 999
nop.i 999
and rint_GR_exponent = rint_GR_signexp, rint_GR_17ones
;;
}
{ .mmi
cmp.ge.unc p7,p6 = rint_GR_exponent, rint_GR_10033
and rint_GR_rcs0 = rint_GR_rcs0_mask, rint_GR_fpsr
nop.i 999
;;
}
// Check to see if s0 rounding mode is round to nearest. If not then set s2
// rounding mode to that of s0 and repeat conversions.
L(RINT_COMMON):
{ .mfb
cmp.ne p11,p0 = rint_GR_rcs0, r0
(p6) fclass.m.unc p9,p10 = RINT_FLOAT_INT_f8, 0x07 // Test for result=0
(p11) br.cond.spnt L(RINT_NOT_ROUND_NEAREST) // Branch if not round to nearest
;;
}
{ .mfi
nop.m 999
(p6) fcmp.eq.unc.s1 p0,p8 = RINT_FLOAT_INT_f8, RINT_NORM_f8
nop.i 999
}
{ .mfi
nop.m 999
(p7) fnorm.d.s0 f8 = f8
nop.i 999
;;
}
// If result is zero, merge sign of input
{ .mfi
nop.m 999
(p9) fmerge.s f8 = f8, RINT_FLOAT_INT_f8
nop.i 999
}
{ .mfi
nop.m 999
(p10) fnorm.d f8 = RINT_FLOAT_INT_f8
nop.i 999
;;
}
{ .mfb
nop.m 999
(p8) fmpy.s0 RINT_INEXACT = RINT_FFFF,RINT_FFFF // Dummy to set inexact
br.ret.sptk b0
;;
}
L(RINT_NOT_ROUND_NEAREST):
// Set rounding mode of s2 to that of s0
{ .mfi
mov rint_GR_rcs0 = r0 // Clear so we don't come back here
fsetc.s2 0x7f, 0x40
nop.i 999
;;
}
{ .mfi
nop.m 999
fcvt.fx.s2 RINT_INT_f8 = f8
nop.i 999
;;
}
{ .mfb
nop.m 999
fcvt.xf RINT_FLOAT_INT_f8 = RINT_INT_f8
br.cond.sptk L(RINT_COMMON)
;;
}
.endp rint
ASM_SIZE_DIRECTIVE(rint)
#ifdef _LIBC
ASM_SIZE_DIRECTIVE(__rint)
#endif
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