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.file "floor.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.
//
.align 32
.global floor#
.section .text
.proc floor#
.align 32
// History
//==============================================================
// 2/02/00: Initial version
// 3/22/00: Updated to improve performance
// 6/13/00: Improved speed, fixed setting of inexact flag
// 6/27/00: Eliminated incorrect invalid flag setting
// 2/07/01: Corrected sign of zero result in round to -inf mode
// API
//==============================================================
// double floor(double x)
// general input registers:
floor_GR_FFFF = r14
floor_GR_signexp = r15
floor_GR_exponent = r16
floor_GR_expmask = r17
floor_GR_bigexp = r18
// predicate registers used:
// p6 ==> Input is NaN, infinity, zero
// p7 ==> Input is denormal
// p8 ==> Input is <0
// p9 ==> Input is >=0
// p10 ==> Input is already an integer (bigger than largest integer)
// p11 ==> Input is not a large integer
// p12 ==> Input is a smaller integer
// p13 ==> Input is not an even integer, so inexact must be set
// floating-point registers used:
FLOOR_NORM_f8 = f9
FLOOR_FFFF = f10
FLOOR_INEXACT = f11
FLOOR_FLOAT_INT_f8 = f12
FLOOR_INT_f8 = f13
FLOOR_adj = f14
// Overview of operation
//==============================================================
// double floor(double x)
// Return an integer value (represented as a double) that is the largest
// value not greater than x
// This is x rounded toward -infinity to an integral value.
// Inexact is set if x != floor(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 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.
// If x is NAN, ZERO, or INFINITY, then return
// qnan snan inf norm unorm 0 -+
// 1 1 1 0 0 1 11 0xe7
#include "libm_support.h"
floor:
#ifdef _LIBC
.global __floor
__floor:
#endif
{ .mfi
getf.exp floor_GR_signexp = f8
fcvt.fx.trunc.s1 FLOOR_INT_f8 = f8
addl floor_GR_bigexp = 0x10033, r0
}
{ .mfi
addl floor_GR_FFFF = -1,r0
fcmp.lt.s1 p8,p9 = f8,f0
mov floor_GR_expmask = 0x1FFFF ;;
}
// p7 ==> denorm
{ .mfi
setf.sig FLOOR_FFFF = floor_GR_FFFF
fclass.m p7,p0 = f8, 0x0b
nop.i 999
}
{ .mfi
nop.m 999
fnorm.s1 FLOOR_NORM_f8 = f8
nop.i 999 ;;
}
// p6 ==> NAN, INF, ZERO
{ .mfb
nop.m 999
fclass.m p6,p10 = f8, 0xe7
(p7) br.cond.spnt L(FLOOR_DENORM) ;;
}
L(FLOOR_COMMON):
.pred.rel "mutex",p8,p9
// Set adjustment to subtract from trunc(x) for result
// If x<0, adjustment is -1.0
// If x>=0, adjustment is 0.0
{ .mfi
and floor_GR_exponent = floor_GR_signexp, floor_GR_expmask
(p8) fnma.s1 FLOOR_adj = f1,f1,f0
nop.i 999
}
{ .mfi
nop.m 999
(p9) fadd.s1 FLOOR_adj = f0,f0
nop.i 999 ;;
}
{ .mfi
nop.m 999
fcmp.eq.s0 p12,p0 = f8,f0 // Dummy op to set denormal and invalid flag
nop.i 999
}
{ .mfi
(p10) cmp.ge.unc p10,p11 = floor_GR_exponent, floor_GR_bigexp
(p6) fnorm.d f8 = f8
nop.i 999 ;;
}
{ .mfi
nop.m 999
(p11) fcvt.xf FLOOR_FLOAT_INT_f8 = FLOOR_INT_f8
nop.i 999 ;;
}
{ .mfi
nop.m 999
(p10) fnorm.d f8 = FLOOR_NORM_f8
nop.i 999 ;;
}
{ .mfi
nop.m 999
(p11) fadd.d f8 = FLOOR_FLOAT_INT_f8,FLOOR_adj
nop.i 999 ;;
}
{ .mfi
nop.m 999
(p11) fcmp.eq.unc.s1 p12,p13 = FLOOR_FLOAT_INT_f8, FLOOR_NORM_f8
nop.i 999 ;;
}
// Set inexact if result not equal to input
{ .mfi
nop.m 999
(p13) fmpy.s0 FLOOR_INEXACT = FLOOR_FFFF,FLOOR_FFFF
nop.i 999
}
// Set result to input if integer
{ .mfb
nop.m 999
(p12) fnorm.d f8 = FLOOR_NORM_f8
br.ret.sptk b0 ;;
}
// Here if input denorm
L(FLOOR_DENORM):
{ .mfb
getf.exp floor_GR_signexp = FLOOR_NORM_f8
fcvt.fx.trunc.s1 FLOOR_INT_f8 = FLOOR_NORM_f8
br.cond.sptk L(FLOOR_COMMON) ;;
}
.endp floor
ASM_SIZE_DIRECTIVE(floor)
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