269 lines
7.9 KiB
ArmAsm
269 lines
7.9 KiB
ArmAsm
.file "ilogb.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
|
|
//==============================================================
|
|
// 02/03/00 Initial version
|
|
// 05/26/00 Fix bug when x a double-extended denormal;
|
|
// if x=0 call error routine, per C9X
|
|
// 08/15/00 Bundle added after call to __libm_error_support to properly
|
|
// set [the previously overwritten] GR_Parameter_RESULT.
|
|
// 01/20/01 Fixed result for x=0, corrected error tag value.
|
|
// 05/20/02 Cleaned up namespace and sf0 syntax
|
|
// 01/20/03 Improved performance
|
|
//
|
|
// API
|
|
//==============================================================
|
|
// int ilogb( double x );
|
|
//
|
|
// Overview of operation
|
|
//==============================================================
|
|
// The ilogb function extracts the exponent of x as an integer
|
|
// and returns it in r8
|
|
//
|
|
// ilogb is similar to logb but differs in the following ways:
|
|
// +-inf
|
|
// ilogb: returns INT_MAX
|
|
// logb: returns +inf
|
|
// Nan returns FP_LOGBNAN (which is either INT_MAX or INT_MIN)
|
|
// ilogb: returns INT_MAX (7fffffff)
|
|
// logb: returns QNAN (quietized SNAN)
|
|
// 0 returns FP_ILOGB0 (which is either INT_MIN or -INT_MAX)
|
|
// ilogb: returns -INT_MAX (80000001)
|
|
// logb: returns -inf, raises the divide-by-zero exception,
|
|
// and calls libm_error_support to set domain error
|
|
//
|
|
// Registers used
|
|
//==============================================================
|
|
// general registers used:
|
|
// r26 -> r39
|
|
// r36 -> r39 used as parameters to error path
|
|
//
|
|
// predicate registers used:
|
|
// p6 -> p10
|
|
// floating-point registers used:
|
|
// f9, f10, f11
|
|
// f8, input
|
|
|
|
rExpBias = r26
|
|
rExpMask = r27
|
|
rSignexp_x = r28
|
|
rExp_x = r29
|
|
rIntMax = r30
|
|
rExp_2to64 = r31
|
|
|
|
GR_SAVE_PFS = r32
|
|
rTrialResult = r33
|
|
GR_SAVE_B0 = r34
|
|
GR_SAVE_GP = r35
|
|
|
|
GR_Parameter_X = r36
|
|
GR_Parameter_Y = r37
|
|
GR_Parameter_RESULT = r38
|
|
GR_Parameter_TAG = r39
|
|
|
|
fTmp = f9
|
|
fNorm_x = f10
|
|
f2to64 = f11
|
|
|
|
.section .text
|
|
GLOBAL_LIBM_ENTRY(ilogb)
|
|
|
|
// X NORMAL
|
|
// TrueExp_x = exp(f8) - 0xffff
|
|
// r8 = TrueExp_x
|
|
{ .mfi
|
|
getf.exp rSignexp_x = f8
|
|
fclass.m p8,p0 = f8, 0x0b // Test for x unorm
|
|
mov rExpBias = 0xffff // Exponent bias
|
|
}
|
|
{ .mfi
|
|
nop.m 0
|
|
fnorm.s1 fNorm_x = f8
|
|
mov rExpMask = 0x1ffff // Exponent mask
|
|
}
|
|
;;
|
|
|
|
// Form signexp of 2^64 in case need to scale denormal
|
|
{ .mfb
|
|
mov rExp_2to64 = 0x1003f
|
|
fclass.m p6,p9 = f8, 0x1e3 // Test x natval, nan, inf
|
|
(p8) br.cond.spnt ILOGB_DENORM // Branch if x unorm
|
|
}
|
|
;;
|
|
|
|
ILOGB_COMMON:
|
|
// Return here from ILOGB_DENORM
|
|
{ .mfi
|
|
and rExp_x = rSignexp_x, rExpMask // Get biased exponent
|
|
fclass.m p7,p10 = f8, 0x07 // Test x zero
|
|
nop.i 0
|
|
}
|
|
{ .mlx
|
|
nop.m 0
|
|
movl rIntMax = 0x000000007fffffff // Form INT_MAX
|
|
}
|
|
;;
|
|
|
|
.pred.rel "mutex",p6,p9
|
|
{ .mfi
|
|
(p9) sub r8 = rExp_x, rExpBias // Get true exponent for normal path
|
|
(p6) fma.s0 fTmp = f8, f8, f0 // Dummy to set Invalid flag
|
|
(p6) mov r8 = rIntMax // If nan, inf, return INT_MAX
|
|
}
|
|
{ .mbb
|
|
nop.m 0
|
|
(p7) br.cond.spnt ILOGB_ZERO // Branch if x zero
|
|
(p10) br.ret.sptk b0 // Exit if x not zero
|
|
}
|
|
;;
|
|
|
|
|
|
ILOGB_DENORM:
|
|
// Form 2^64 in case need to scale denormal
|
|
// Check to see if double-extended denormal
|
|
{ .mfi
|
|
setf.exp f2to64 = rExp_2to64
|
|
fclass.m p8,p0 = fNorm_x, 0x0b
|
|
nop.i 0
|
|
}
|
|
;;
|
|
|
|
{ .mfi
|
|
nop.m 0
|
|
fcmp.eq.s0 p7,p0 = f8, f0 // Dummy op to set denormal flag
|
|
nop.i 0
|
|
}
|
|
;;
|
|
|
|
// If double-extended denormal add 64 to exponent bias for scaling
|
|
// If double-extended denormal form x * 2^64 which is normal
|
|
{ .mfi
|
|
(p8) add rExpBias = 64, rExpBias
|
|
(p8) fmpy.s1 fNorm_x = fNorm_x, f2to64
|
|
nop.i 0
|
|
}
|
|
;;
|
|
|
|
// Logic is the same as normal path but use normalized input
|
|
{ .mib
|
|
getf.exp rSignexp_x = fNorm_x
|
|
nop.i 0
|
|
br.cond.sptk ILOGB_COMMON // Return to main path
|
|
}
|
|
;;
|
|
|
|
ILOGB_ZERO:
|
|
// Here if x zero
|
|
// Return INT_MIN, call error support
|
|
|
|
{ .mlx
|
|
alloc r32=ar.pfs,1,3,4,0
|
|
movl rTrialResult = 0x0000000080000000
|
|
}
|
|
{ .mib
|
|
mov GR_Parameter_TAG = 157 // Error code
|
|
nop.i 0
|
|
br.cond.sptk __libm_error_region // Call error support
|
|
}
|
|
;;
|
|
|
|
GLOBAL_LIBM_END(ilogb)
|
|
|
|
|
|
LOCAL_LIBM_ENTRY(__libm_error_region)
|
|
.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] = f0,16 // 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] = f8 // STORE Parameter 1 on stack
|
|
add GR_Parameter_RESULT = 0,GR_Parameter_Y // Parameter 3 address
|
|
nop.b 0
|
|
}
|
|
{ .mib
|
|
stfd [GR_Parameter_Y] = f9 // 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
|
|
mov r8 = rTrialResult
|
|
.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
|
|
};;
|
|
|
|
LOCAL_LIBM_END(__libm_error_region)
|
|
|
|
|
|
.type __libm_error_support#,@function
|
|
.global __libm_error_support#
|