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glibc/ports/sysdeps/ia64/fpu/s_libm_ldexpf.S

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.file "libm_ldexpf.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
//==============================================================
// 02/02/00 Initial version
// 01/26/01 ldexpf completely reworked and now standalone version
// 01/04/02 Added handling for int 32 or 64 bits
// 05/20/02 Cleaned up namespace and sf0 syntax
// 02/10/03 Reordered header: .section, .global, .proc, .align
// 08/04/03 Improved performance
//
// API
//==============================================================
// float __libm_ldexpf (float x, int n, int int_type)
// input floating point f8 and int n (r33), int int_type (r34)
// output floating point f8
//
// int_type = 0 if int is 32 bits
// int_type = 1 if int is 64 bits
//
// Returns x* 2**n using an fma and detects overflow
// and underflow.
//
//
// Strategy:
// Compute biased exponent of result exp_Result = N + exp_X
// Break into ranges:
// exp_Result > 0x1007e -> Certain overflow
// exp_Result = 0x1007e -> Possible overflow
// 0x0ff81 <= exp_Result < 0x1007e -> No over/underflow (main path)
// 0x0ff81 - 23 <= exp_Result < 0x0ff81 -> Possible underflow
// exp_Result < 0x0ff81 - 23 -> Certain underflow
FR_Big = f6
FR_NBig = f7
FR_Floating_X = f8
FR_Result = f8
FR_Result2 = f9
FR_Result3 = f10
FR_Norm_X = f11
FR_Two_N = f12
GR_neg_ov_limit= r14
GR_N_Biased = r15
GR_Big = r16
GR_NBig = r17
GR_exp_Result = r18
GR_pos_ov_limit= r19
GR_Bias = r20
GR_N_as_int = r21
GR_signexp_X = r22
GR_exp_X = r23
GR_exp_mask = r24
GR_max_exp = r25
GR_min_exp = r26
GR_min_den_exp = r27
GR_SAVE_B0 = r32
GR_SAVE_GP = r33
GR_SAVE_PFS = r34
GR_Parameter_X = r35
GR_Parameter_Y = r36
GR_Parameter_RESULT = r37
GR_Tag = r38
.section .text
GLOBAL_LIBM_ENTRY(__libm_ldexpf)
//
// Is x NAN, INF, ZERO, +-?
// Build the exponent Bias
//
{ .mfi
getf.exp GR_signexp_X = FR_Floating_X // Get signexp of x
fclass.m p6,p0 = FR_Floating_X, 0xe7 // @snan | @qnan | @inf | @zero
mov GR_Bias = 0x0ffff
}
//
// Normalize x
// Is integer type 32 bits?
//
{ .mfi
mov GR_Big = 35000 // If N this big then certain overflow
fnorm.s1 FR_Norm_X = FR_Floating_X
cmp.eq p8,p9 = r34,r0
}
;;
// Sign extend N if int is 32 bits
{ .mfi
(p9) mov GR_N_as_int = r33 // Copy N if int is 64 bits
fclass.m p9,p0 = FR_Floating_X, 0x0b // Test for x=unorm
(p8) sxt4 GR_N_as_int = r33 // Sign extend N if int is 32 bits
}
{ .mfi
mov GR_NBig = -35000 // If N this small then certain underflow
nop.f 0
mov GR_max_exp = 0x1007e // Exponent of maximum float
}
;;
// Create biased exponent for 2**N
{ .mfi
add GR_N_Biased = GR_Bias,GR_N_as_int
nop.f 0
cmp.ge p7, p0 = GR_N_as_int, GR_Big // Certain overflow?
}
{ .mib
cmp.le p8, p0 = GR_N_as_int, GR_NBig // Certain underflow?
mov GR_min_exp = 0x0ff81 // Exponent of minimum float
(p9) br.cond.spnt LDEXPF_UNORM // Branch if x=unorm
}
;;
LDEXPF_COMMON:
// Main path continues. Also return here from x=unorm path.
// Create 2**N
.pred.rel "mutex",p7,p8
{ .mfi
setf.exp FR_Two_N = GR_N_Biased
nop.f 0
(p7) mov GR_N_as_int = GR_Big // Limit max N
}
{ .mfi
(p8) mov GR_N_as_int = GR_NBig // Limit min N
nop.f 0
(p8) cmp.eq p7,p0 = r0,r0 // Set p7 if |N| big
}
;;
//
// Create biased exponent for 2**N for N big
// Is N zero?
//
{ .mfi
(p7) add GR_N_Biased = GR_Bias,GR_N_as_int
nop.f 0
cmp.eq.or p6,p0 = r33,r0
}
{ .mfi
mov GR_pos_ov_limit = 0x1007f // Exponent for positive overflow
nop.f 0
mov GR_exp_mask = 0x1ffff // Exponent mask
}
;;
//
// Create 2**N for N big
// Return x when N = 0 or X = Nan, Inf, Zero
//
{ .mfi
(p7) setf.exp FR_Two_N = GR_N_Biased
nop.f 0
mov GR_min_den_exp = 0x0ff81 - 23 // Exponent of min denorm float
}
{ .mfb
and GR_exp_X = GR_exp_mask, GR_signexp_X
(p6) fma.s.s0 FR_Result = FR_Floating_X, f1, f0
(p6) br.ret.spnt b0
}
;;
//
// Raise Denormal operand flag with compare
// Compute biased result exponent
//
{ .mfi
add GR_exp_Result = GR_exp_X, GR_N_as_int
fcmp.ge.s0 p0,p11 = FR_Floating_X,f0
mov GR_neg_ov_limit = 0x3007f // Exponent for negative overflow
}
;;
//
// Do final operation
//
{ .mfi
cmp.lt p7,p6 = GR_exp_Result, GR_max_exp // Test no overflow
fma.s.s0 FR_Result = FR_Two_N,FR_Norm_X,f0
cmp.lt p9,p0 = GR_exp_Result, GR_min_den_exp // Test sure underflow
}
{ .mfb
nop.m 0
nop.f 0
(p9) br.cond.spnt LDEXPF_UNDERFLOW // Branch if certain underflow
}
;;
{ .mib
(p6) cmp.gt.unc p6,p8 = GR_exp_Result, GR_max_exp // Test sure overflow
(p7) cmp.ge.unc p7,p9 = GR_exp_Result, GR_min_exp // Test no over/underflow
(p7) br.ret.sptk b0 // Return from main path
}
;;
{ .bbb
(p6) br.cond.spnt LDEXPF_OVERFLOW // Branch if certain overflow
(p8) br.cond.spnt LDEXPF_POSSIBLE_OVERFLOW // Branch if possible overflow
(p9) br.cond.spnt LDEXPF_POSSIBLE_UNDERFLOW // Branch if possible underflow
}
;;
// Here if possible underflow.
// Resulting exponent: 0x0ff81-23 <= exp_Result < 0x0ff81
LDEXPF_POSSIBLE_UNDERFLOW:
//
// Here if possible overflow.
// Resulting exponent: 0x1007e = exp_Result
LDEXPF_POSSIBLE_OVERFLOW:
// Set up necessary status fields
//
// S0 user supplied status
// S2 user supplied status + WRE + TD (Overflows)
// S3 user supplied status + FZ + TD (Underflows)
//
{ .mfi
nop.m 0
fsetc.s3 0x7F,0x41
nop.i 0
}
{ .mfi
nop.m 0
fsetc.s2 0x7F,0x42
nop.i 0
}
;;
//
// Do final operation with s2 and s3
//
{ .mfi
setf.exp FR_NBig = GR_neg_ov_limit
fma.s.s3 FR_Result3 = FR_Two_N,FR_Norm_X,f0
nop.i 0
}
{ .mfi
setf.exp FR_Big = GR_pos_ov_limit
fma.s.s2 FR_Result2 = FR_Two_N,FR_Norm_X,f0
nop.i 0
}
;;
// Check for overflow or underflow.
// Restore s3
// Restore s2
//
{ .mfi
nop.m 0
fsetc.s3 0x7F,0x40
nop.i 0
}
{ .mfi
nop.m 0
fsetc.s2 0x7F,0x40
nop.i 0
}
;;
//
// Is the result zero?
//
{ .mfi
nop.m 0
fclass.m p6, p0 = FR_Result3, 0x007
nop.i 0
}
{ .mfi
nop.m 0
fcmp.ge.s1 p7, p8 = FR_Result2 , FR_Big
nop.i 0
}
;;
//
// Detect masked underflow - Tiny + Inexact Only
//
{ .mfi
nop.m 0
(p6) fcmp.neq.unc.s1 p6, p0 = FR_Result , FR_Result2
nop.i 0
}
;;
//
// Is result bigger the allowed range?
// Branch out for underflow
//
{ .mfb
nop.m 0
(p8) fcmp.le.unc.s1 p9, p10 = FR_Result2 , FR_NBig
(p6) br.cond.spnt LDEXPF_UNDERFLOW
}
;;
//
// Branch out for overflow
//
{ .bbb
(p7) br.cond.spnt LDEXPF_OVERFLOW
(p9) br.cond.spnt LDEXPF_OVERFLOW
br.ret.sptk b0 // Return from main path.
}
;;
// Here if result overflows
LDEXPF_OVERFLOW:
{ .mib
alloc r32=ar.pfs,3,0,4,0
addl GR_Tag = 148, r0 // Set error tag for overflow
br.cond.sptk __libm_error_region // Call error support for overflow
}
;;
// Here if result underflows
LDEXPF_UNDERFLOW:
{ .mib
alloc r32=ar.pfs,3,0,4,0
addl GR_Tag = 149, r0 // Set error tag for underflow
br.cond.sptk __libm_error_region // Call error support for underflow
}
;;
// Here if x=unorm
LDEXPF_UNORM:
{ .mib
getf.exp GR_signexp_X = FR_Norm_X // Get signexp of normalized x
nop.i 0
br.cond.sptk LDEXPF_COMMON // Return to main path
}
;;
GLOBAL_LIBM_END(__libm_ldexpf)
LOCAL_LIBM_ENTRY(__libm_error_region)
//
// Get stack address of N
//
.prologue
{ .mfi
add GR_Parameter_Y=-32,sp
nop.f 0
.save ar.pfs,GR_SAVE_PFS
mov GR_SAVE_PFS=ar.pfs
}
//
// Adjust sp
//
{ .mfi
.fframe 64
add sp=-64,sp
nop.f 0
mov GR_SAVE_GP=gp
};;
//
// Store N on stack in correct position
// Locate the address of x on stack
//
{ .mmi
st8 [GR_Parameter_Y] = GR_N_as_int,16
add GR_Parameter_X = 16,sp
.save b0, GR_SAVE_B0
mov GR_SAVE_B0=b0
};;
//
// Store x on the stack.
// Get address for result on stack.
//
.body
{ .mib
stfs [GR_Parameter_X] = FR_Norm_X
add GR_Parameter_RESULT = 0,GR_Parameter_Y
nop.b 0
}
{ .mib
stfs [GR_Parameter_Y] = FR_Result
add GR_Parameter_Y = -16,GR_Parameter_Y
br.call.sptk b0=__libm_error_support#
};;
//
// Get location of result on stack
//
{ .mmi
add GR_Parameter_RESULT = 48,sp
nop.m 0
nop.i 0
};;
//
// Get the new result
//
{ .mmi
ldfs FR_Result = [GR_Parameter_RESULT]
.restore sp
add sp = 64,sp
mov b0 = GR_SAVE_B0
};;
//
// Restore gp, ar.pfs and return
//
{ .mib
mov gp = GR_SAVE_GP
mov ar.pfs = GR_SAVE_PFS
br.ret.sptk b0
};;
LOCAL_LIBM_END(__libm_error_region)
.type __libm_error_support#,@function
.global __libm_error_support#
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