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102 lines
3.1 KiB
ArmAsm
102 lines
3.1 KiB
ArmAsm
/* sqrtf function. PowerPC32 version.
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Copyright (C) 2007-2013 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <sysdep.h>
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#include <math_ldbl_opt.h>
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/* float [fp1] sqrts (float x [fp1])
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Power4 (ISA V2.0) and above implement sqrt in hardware (not optional).
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The fsqrts instruction generates the correct value for all inputs and
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sets the appropriate floating point exceptions. Extended checking is
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only needed to set errno (via __kernel_standard) if the input value
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is negative.
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The fsqrts will set FPCC and FU (Floating Point Unordered or NaN
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to indicated that the input value was negative or NaN. Use Move to
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Condition Register from FPSCR to copy the FPCC field to cr1. The
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branch on summary overflow transfers control to w_sqrt to process
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any error conditions. Otherwise we can return the result directly.
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This part of the function is a leaf routine, so no need to stack a
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frame or execute prologue/epilogue code. This means it is safe to
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transfer directly to w_sqrt as long as the input value (f1) is
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preserved. Putting the sqrt result into f2 (float parameter 2)
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allows passing both the input value and sqrt result into the extended
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wrapper so there is no need to recompute.
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This tactic avoids the overhead of stacking a frame for the normal
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(non-error) case. Until gcc supports prologue shrink-wrapping
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this is the best we can do. */
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.section ".text"
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.machine power4
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EALIGN (__sqrtf, 5, 0)
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fsqrts fp2,fp1
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mcrfs cr1,4
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bso- cr1,.Lw_sqrtf
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fmr fp1,fp2
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blr
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.align 4
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.Lw_sqrtf:
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mflr r0
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stwu r1,-16(r1)
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cfi_adjust_cfa_offset(16)
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fmr fp12,fp2
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stw r0,20(r1)
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stw r30,8(r1)
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cfi_offset(lr,20-16)
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cfi_offset(r30,8-16)
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#ifdef SHARED
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SETUP_GOT_ACCESS(r30,got_label)
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addis r30,r30,_GLOBAL_OFFSET_TABLE_-got_label@ha
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addi r30,r30,_GLOBAL_OFFSET_TABLE_-got_label@l
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lwz r9,_LIB_VERSION@got(30)
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lwz r0,0(r9)
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#else
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lis r9,_LIB_VERSION@ha
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lwz r0,_LIB_VERSION@l(r9)
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#endif
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/* if (_LIB_VERSION == _IEEE_) return z; */
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cmpwi cr7,r0,-1
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beq- cr7,.L4
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/* if (x != x, 0) return z; !isnan */
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fcmpu cr7,fp1,fp1
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bne- cr7,.L4
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/* if (x < 0.0)
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return __kernel_standard (x, x, 126) */
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fmr fp2,fp1
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fabs fp0,fp1
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li r3,126
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fcmpu cr7,1,0
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bne- cr7,.L11
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.L4:
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lwz r0,20(r1)
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fmr fp1,fp12
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lwz r30,8(r1)
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addi r1,r1,16
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mtlr r0
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blr
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.L11:
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bl __kernel_standard@plt
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fmr fp12,fp1
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b .L4
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END (__sqrtf)
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weak_alias (__sqrtf, sqrtf)
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