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

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;------------------------------------------------------------------------------
;
; 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.
;
;------------------------------------------------------------------------------
EXPORT SetJump
EXPORT InternalLongJump
AREA BaseLib_LowLevel, CODE, READONLY
#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
; );
;
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
; );
;
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
beq exit
mov w0, w1
exit
// use br not ret, as ret is guaranteed to mispredict
br x30
ASM_FUNCTION_REMOVE_IF_UNREFERENCED
END