audk/ArmPkg/Library/ArmSvcLib/Arm/ArmSvc.asm

40 lines
1.1 KiB
NASM

//
// Copyright (c) 2016 - 2017, ARM Limited. All rights reserved.
//
// 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.
//
//
INCLUDE AsmMacroExport.inc
RVCT_ASM_EXPORT ArmCallSvc
// r0 will be popped just after the SVC call
push {r0, r4-r8}
// Load the SVC arguments values into the appropriate registers
ldm r0, {r0-r7}
svc #0
// Load the ARM_SVC_ARGS structure address from the stack into r8
ldr r8, [sp]
// Load the SVC returned values into the appropriate registers
// A SVC call can return up to 4 values - we do not need to store back r4-r7.
stm r8, {r0-r3}
mov r0, r8
// Restore the registers r4-r8
pop {r1, r4-r8}
bx lr
END