audk/MdePkg/Library/BaseLib/AArch64/SetJumpLongJump.S

98 lines
3.2 KiB
ArmAsm

#------------------------------------------------------------------------------
#
# Copyright (c) 2009-2013, ARM Ltd. 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.
#
#------------------------------------------------------------------------------
.text
.p2align 3
GCC_ASM_EXPORT(SetJump)
GCC_ASM_EXPORT(InternalLongJump)
#define GPR_LAYOUT \
REG_PAIR (x19, x20, 0); \
REG_PAIR (x21, x22, 16); \
REG_PAIR (x23, x24, 32); \
REG_PAIR (x25, x26, 48); \
REG_PAIR (x27, x28, 64); \
REG_PAIR (x29, x30, 80);/*FP, LR*/ \
REG_ONE (x16, 96) /*IP0*/
#define FPR_LAYOUT \
REG_PAIR ( d8, d9, 112); \
REG_PAIR (d10, d11, 128); \
REG_PAIR (d12, d13, 144); \
REG_PAIR (d14, d15, 160);
#/**
# Saves the current CPU context that can be restored with a call to LongJump() and returns 0.#
#
# Saves the current CPU context in the buffer specified by JumpBuffer and returns 0. The initial
# call to SetJump() must always return 0. Subsequent calls to LongJump() cause a non-zero
# value to be returned by SetJump().
#
# If JumpBuffer is NULL, then ASSERT().
# For IPF CPUs, if JumpBuffer is not aligned on a 16-byte boundary, then ASSERT().
#
# @param JumpBuffer A pointer to CPU context buffer.
#
#**/
#
#UINTN
#EFIAPI
#SetJump (
# IN BASE_LIBRARY_JUMP_BUFFER *JumpBuffer // X0
# );
#
ASM_PFX(SetJump):
mov x16, sp // use IP0 so save SP
#define REG_PAIR(REG1, REG2, OFFS) stp REG1, REG2, [x0, OFFS]
#define REG_ONE(REG1, OFFS) str REG1, [x0, OFFS]
GPR_LAYOUT
FPR_LAYOUT
#undef REG_PAIR
#undef REG_ONE
mov w0, #0
ret
#/**
# Restores the CPU context that was saved with SetJump().#
#
# Restores the CPU context from the buffer specified by JumpBuffer.
# This function never returns to the caller.
# Instead is resumes execution based on the state of JumpBuffer.
#
# @param JumpBuffer A pointer to CPU context buffer.
# @param Value The value to return when the SetJump() context is restored.
#
#**/
#VOID
#EFIAPI
#InternalLongJump (
# IN BASE_LIBRARY_JUMP_BUFFER *JumpBuffer, // X0
# IN UINTN Value // X1
# );
#
ASM_PFX(InternalLongJump):
#define REG_PAIR(REG1, REG2, OFFS) ldp REG1, REG2, [x0, OFFS]
#define REG_ONE(REG1, OFFS) ldr REG1, [x0, OFFS]
GPR_LAYOUT
FPR_LAYOUT
#undef REG_PAIR
#undef REG_ONE
mov sp, x16
cmp w1, #0
mov w0, #1
csel w0, w1, w0, ne
// use br not ret, as ret is guaranteed to mispredict
br x30
ASM_FUNCTION_REMOVE_IF_UNREFERENCED