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#
# Copyright (c) 2008 - 2010, Apple Inc. All rights reserved.<BR>
#
# This program and the accompanying materials
# are licensed and made available under the terms and conditions of the BSD License
# which accompanies this distribution.  The full text of the license may be found at
# http://opensource.org/licenses/bsd-license.php
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# THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
# WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
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#------------------------------------------------------------------------------

#include <AsmMacroIoLib.h>

/*
  Semihosting operation request mechanism

  SVC  0x123456  in ARM state (for all architectures)
  SVC  0xAB in Thumb state (excluding ARMv7-M)
  BKPT 0xAB for ARMv7-M (Thumb-2 only)

  R0 - operation type
  R1 - block containing all other parametes

  lr - must be saved as svc instruction will cause an svc exception and write
       the svc lr register. That happens to be the one we are using, so we must
       save it or we will not be able to return.
 */
ASM_FUNC(GccSemihostCall)
  stmfd   sp!, {lr}
  svc     #0x123456
  ldmfd   sp!, {lr}
  bx      lr


