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.file "fdim.s"
// Copyright (c) 2001 - 2003, Intel Corporation
// All rights reserved.
//
// Contributed 2001 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
//==============================================================
// 06/08/01 Initial version
// 08/23/01 Corrected error tag number
// 05/20/02 Cleaned up namespace and sf0 syntax
// 01/28/03 Improved performance
//
// API
//==============================================================
// double fdim( double x, double y );
// input floating point f8, f9
// output floating point f8
//
//
// Overview of operation
//==============================================================
// fdim determines the positive difference between the arguments
// Result = x - y if x > y
// = +0 if x <= y
//
// Error support is called if x-y overflows for x > y
//
// Registers used
//==============================================================
// General purpose registers: r14, r32 - r39
rExpBig = r14
// r36-39 parameters for libm_error_support
GR_SAVE_B0 = r33
GR_SAVE_GP = r34
GR_SAVE_PFS = r35
GR_Parameter_X = r36
GR_Parameter_Y = r37
GR_Parameter_RESULT = r38
GR_Parameter_TAG = r39
// Floating-point registers: f8 - f12
f_tmp_result = f10
fBig = f11
fNormX = f12
// Predicate registers: p6 - p10
.section .text
GLOBAL_LIBM_ENTRY(fdim)
{ .mfi
mov rExpBig = 0x103ff // Exponent to indicate overflow
fcmp.le.s1 p6,p7 = f8, f9 // Is x <= y?
nop.i 0
}
{ .mfi
nop.m 0
fnorm.s1 fNormX = f8 // Save x
nop.i 0
}
;;
{ .mfi
setf.exp fBig = rExpBig // Constant to test for overflow
fcmp.eq.s0 p8,p0 = f8, f9 // Dummy op to set Denormal or Invalid
nop.i 0
}
;;
{ .mfi
nop.m 0
fclass.m p9,p10 = f8, 0x1e3 // Test for x natval, nan, inf
nop.i 0
}
;;
{ .mfi
nop.m 0
(p6) fmerge.s f8 = f0, f0 // Result is +0 if x <= y
nop.i 0
}
{ .mfi
nop.m 0
(p7) fms.d.s0 f8 = f8, f1, f9 // Result is x - y if x > y
nop.i 0
}
;;
{ .mfi
nop.m 0
(p10) fclass.m p9,p10 = f9, 0x1e3 // Test for y natval, nan, inf
nop.i 0
}
;;
{ .mfi
nop.m 0
(p10) fcmp.ge.s1 p8,p0 = f8, fBig // Test result for overflow
nop.i 0
}
;;
{ .mbb
(p9) cmp.ne p8,p0 = r0,r0 // Clear p8 if x or y natval,nan,inf
(p8) br.cond.spnt FDIM_OVERFLOW // Branch if result overflows
br.ret.sptk b0 // Normal return
}
;;
// Here if result will overflow
FDIM_OVERFLOW:
{ .mfi
alloc r32=ar.pfs,2,2,4,0
fms.d.s0 f_tmp_result = f8,f1,f9 // Normalize result force overflow
nop.i 0
}
{ .mfb
mov GR_Parameter_TAG = 196 // Error code
nop.f 0
br.cond.sptk __libm_error_region // Branch to error code
}
;;
GLOBAL_LIBM_END(fdim)
LOCAL_LIBM_ENTRY(__libm_error_region)
// Call error support to report possible range error
.prologue
{ .mfi
add GR_Parameter_Y=-32,sp // Parameter 2 value
nop.f 0
.save ar.pfs,GR_SAVE_PFS
mov GR_SAVE_PFS=ar.pfs // Save ar.pfs
}
{ .mfi
.fframe 64
add sp=-64,sp // Create new stack
nop.f 0
mov GR_SAVE_GP=gp // Save gp
};;
{ .mmi
stfd [GR_Parameter_Y] = f9,16 // STORE Parameter 2 on stack
add GR_Parameter_X = 16,sp // Parameter 1 address
.save b0, GR_SAVE_B0
mov GR_SAVE_B0=b0 // Save b0
};;
.body
{ .mib
stfd [GR_Parameter_X] = fNormX // STORE Parameter 1 on stack
add GR_Parameter_RESULT = 0,GR_Parameter_Y // Parameter 3 address
nop.b 0
}
{ .mib
stfd [GR_Parameter_Y] = f_tmp_result // STORE Parameter 3 on stack
add GR_Parameter_Y = -16,GR_Parameter_Y
br.call.sptk b0=__libm_error_support# // Call error handling function
};;
{ .mmi
add GR_Parameter_RESULT = 48,sp
nop.m 0
nop.i 0
};;
{ .mmi
ldfd f8 = [GR_Parameter_RESULT] // Get return result off stack
.restore sp
add sp = 64,sp // Restore stack pointer
mov b0 = GR_SAVE_B0 // Restore return address
};;
{ .mib
mov gp = GR_SAVE_GP // Restore gp
mov ar.pfs = GR_SAVE_PFS // Restore ar.pfs
br.ret.sptk b0 // Return
};;
LOCAL_LIBM_END(__libm_error_region)
.type __libm_error_support#,@function
.global __libm_error_support#
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