MdePkg/Library/BaseLib/AArch64/SetJumpLongJump.asm

   1 ;------------------------------------------------------------------------------
   2 ;
   3 ; Copyright (c) 2009-2013, ARM Ltd.  All rights reserved.
   4 ; This program and the accompanying materials
   5 ; are licensed and made available under the terms and conditions of the BSD License
   6 ; which accompanies this distribution.  The full text of the license may be found at
   7 ; http://opensource.org/licenses/bsd-license.php.
   8 ;
   9 ; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  10 ; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  11 ;
  12 ;------------------------------------------------------------------------------
  13
  14   EXPORT SetJump
  15   EXPORT InternalLongJump
  16   AREA BaseLib_LowLevel, CODE, READONLY
  17
  18 #define GPR_LAYOUT                          \
  19         REG_PAIR (x19, x20,  #0);           \
  20         REG_PAIR (x21, x22, #16);           \
  21         REG_PAIR (x23, x24, #32);           \
  22         REG_PAIR (x25, x26, #48);           \
  23         REG_PAIR (x27, x28, #64);           \
  24         REG_PAIR (x29, x30, #80);/*FP, LR*/ \
  25         REG_ONE  (x16,      #96) /*IP0*/
  26
  27 #define FPR_LAYOUT                       \
  28         REG_PAIR ( d8,  d9, #112);       \
  29         REG_PAIR (d10, d11, #128);       \
  30         REG_PAIR (d12, d13, #144);       \
  31         REG_PAIR (d14, d15, #160);
  32
  33 ;/**
  34 ;  Saves the current CPU context that can be restored with a call to LongJump() and returns 0.#
  35 ;
  36 ;  Saves the current CPU context in the buffer specified by JumpBuffer and returns 0.  The initial
  37 ;  call to SetJump() must always return 0.  Subsequent calls to LongJump() cause a non-zero
  38 ;  value to be returned by SetJump().
  39 ;
  40 ;  If JumpBuffer is NULL, then ASSERT().
  41 ;  For IPF CPUs, if JumpBuffer is not aligned on a 16-byte boundary, then ASSERT().
  42 ;
  43 ;  @param  JumpBuffer    A pointer to CPU context buffer.
  44 ;
  45 ;**/
  46 ;
  47 ;UINTN
  48 ;EFIAPI
  49 ;SetJump (
  50 ;  IN      BASE_LIBRARY_JUMP_BUFFER  *JumpBuffer  // X0
  51 ;  );
  52 ;
  53 SetJump
  54         mov     x16, sp // use IP0 so save SP
  55 #define REG_PAIR(REG1, REG2, OFFS)      stp REG1, REG2, [x0, OFFS]
  56 #define REG_ONE(REG1, OFFS)             str REG1, [x0, OFFS]
  57         GPR_LAYOUT
  58         FPR_LAYOUT
  59 #undef REG_PAIR
  60 #undef REG_ONE
  61         mov     w0, #0
  62         ret
  63
  64 ;/**
  65 ;  Restores the CPU context that was saved with SetJump().#
  66 ;
  67 ;  Restores the CPU context from the buffer specified by JumpBuffer.
  68 ;  This function never returns to the caller.
  69 ;  Instead is resumes execution based on the state of JumpBuffer.
  70 ;
  71 ;  @param  JumpBuffer    A pointer to CPU context buffer.
  72 ;  @param  Value         The value to return when the SetJump() context is restored.
  73 ;
  74 ;**/
  75 ;VOID
  76 ;EFIAPI
  77 ;InternalLongJump (
  78 ;  IN      BASE_LIBRARY_JUMP_BUFFER  *JumpBuffer,  // X0
  79 ;  IN      UINTN                     Value         // X1
  80 ;  );
  81 ;
  82 InternalLongJump
  83 #define REG_PAIR(REG1, REG2, OFFS)      ldp REG1, REG2, [x0, OFFS]
  84 #define REG_ONE(REG1, OFFS)             ldr REG1, [x0, OFFS]
  85         GPR_LAYOUT
  86         FPR_LAYOUT
  87 #undef REG_PAIR
  88 #undef REG_ONE
  89         mov     sp, x16
  90         cmp     w1, #0
  91         mov     w0, #1
  92         beq     exit
  93         mov     w0, w1
  94 exit
  95         // use br not ret, as ret is guaranteed to mispredict
  96         br      x30
  97
  98 ASM_FUNCTION_REMOVE_IF_UNREFERENCED
  99
 100   END
 101