[mirror_edk2.git] / ArmPkg / Library / SemihostLib / Arm / GccSemihost.S

#------------------------------------------------------------------------------ 
#
# 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
#
# THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
# WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
#
#------------------------------------------------------------------------------

.text
.align 2

.globl ASM_PFX(GccSemihostCall)
INTERWORK_FUNC(GccSemihostCall)

/*
  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_PFX(GccSemihostCall):
  stmfd   sp!, {lr} \r
  svc     #0x123456  
  ldmfd   sp!, {lr}\r
  bx      lr
Commit	Line	Data
d9629029	1	#------------------------------------------------------------------------------
	2	#
	3	# Copyright (c) 2008 - 2010, Apple Inc. All rights reserved.<BR>
	4	#
	5	# This program and the accompanying materials
	6	# are licensed and made available under the terms and conditions of the BSD License
	7	# which accompanies this distribution. The full text of the license may be found at
	8	# http://opensource.org/licenses/bsd-license.php
	9	#
	10	# THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
	11	# WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
	12	#
	13	#------------------------------------------------------------------------------
	14
	15	.text
	16	.align 2
	17
	18	.globl ASM_PFX(GccSemihostCall)
	19	INTERWORK_FUNC(GccSemihostCall)
	20
	21	/*
	22	Semihosting operation request mechanism
	23
	24	SVC 0x123456 in ARM state (for all architectures)
	25	SVC 0xAB in Thumb state (excluding ARMv7-M)
	26	BKPT 0xAB for ARMv7-M (Thumb-2 only)
	27
	28	R0 - operation type
7d952405	29	R1 - block containing all other parametes
	30
	31	lr - must be saved as svc instruction will cause an svc exception and write
	32	the svc lr register. That happens to be the one we are using, so we must
	33	save it or we will not be able to return.
d9629029	34	*/
d9629029	35	ASM_PFX(GccSemihostCall):
7d952405	36	stmfd sp!, {lr} \r
d9629029	37	svc #0x123456
7d952405	38	ldmfd sp!, {lr}\r
d9629029	39	bx lr
	40
	41