MdePkg/Library/BaseLib/AArch64/SetJumpLongJump.asm

   1 ;------------------------------------------------------------------------------
   2 ;
   3 ; Copyright (c) 2009-2013, ARM Ltd.  All rights reserved.
   4 ; SPDX-License-Identifier: BSD-2-Clause-Patent
   5 ;
   6 ;------------------------------------------------------------------------------
   7
   8   EXPORT SetJump
   9   EXPORT InternalLongJump
  10   AREA BaseLib_LowLevel, CODE, READONLY
  11
  12 #define GPR_LAYOUT                          \
  13         REG_PAIR (x19, x20,  #0);           \
  14         REG_PAIR (x21, x22, #16);           \
  15         REG_PAIR (x23, x24, #32);           \
  16         REG_PAIR (x25, x26, #48);           \
  17         REG_PAIR (x27, x28, #64);           \
  18         REG_PAIR (x29, x30, #80);/*FP, LR*/ \
  19         REG_ONE  (x16,      #96) /*IP0*/
  20
  21 #define FPR_LAYOUT                       \
  22         REG_PAIR ( d8,  d9, #104);       \
  23         REG_PAIR (d10, d11, #120);       \
  24         REG_PAIR (d12, d13, #136);       \
  25         REG_PAIR (d14, d15, #152);
  26
  27 ;/**
  28 ;  Saves the current CPU context that can be restored with a call to LongJump() and returns 0.#
  29 ;
  30 ;  Saves the current CPU context in the buffer specified by JumpBuffer and returns 0.  The initial
  31 ;  call to SetJump() must always return 0.  Subsequent calls to LongJump() cause a non-zero
  32 ;  value to be returned by SetJump().
  33 ;
  34 ;  If JumpBuffer is NULL, then ASSERT().
  35 ;  For IPF CPUs, if JumpBuffer is not aligned on a 16-byte boundary, then ASSERT().
  36 ;
  37 ;  @param  JumpBuffer    A pointer to CPU context buffer.
  38 ;
  39 ;**/
  40 ;
  41 ;UINTN
  42 ;EFIAPI
  43 ;SetJump (
  44 ;  IN      BASE_LIBRARY_JUMP_BUFFER  *JumpBuffer  // X0
  45 ;  );
  46 ;
  47 SetJump
  48         mov     x16, sp // use IP0 so save SP
  49 #define REG_PAIR(REG1, REG2, OFFS)      stp REG1, REG2, [x0, OFFS]
  50 #define REG_ONE(REG1, OFFS)             str REG1, [x0, OFFS]
  51         GPR_LAYOUT
  52         FPR_LAYOUT
  53 #undef REG_PAIR
  54 #undef REG_ONE
  55         mov     w0, #0
  56         ret
  57
  58 ;/**
  59 ;  Restores the CPU context that was saved with SetJump().#
  60 ;
  61 ;  Restores the CPU context from the buffer specified by JumpBuffer.
  62 ;  This function never returns to the caller.
  63 ;  Instead is resumes execution based on the state of JumpBuffer.
  64 ;
  65 ;  @param  JumpBuffer    A pointer to CPU context buffer.
  66 ;  @param  Value         The value to return when the SetJump() context is restored.
  67 ;
  68 ;**/
  69 ;VOID
  70 ;EFIAPI
  71 ;InternalLongJump (
  72 ;  IN      BASE_LIBRARY_JUMP_BUFFER  *JumpBuffer,  // X0
  73 ;  IN      UINTN                     Value         // X1
  74 ;  );
  75 ;
  76 InternalLongJump
  77 #define REG_PAIR(REG1, REG2, OFFS)      ldp REG1, REG2, [x0, OFFS]
  78 #define REG_ONE(REG1, OFFS)             ldr REG1, [x0, OFFS]
  79         GPR_LAYOUT
  80         FPR_LAYOUT
  81 #undef REG_PAIR
  82 #undef REG_ONE
  83         mov     sp, x16
  84         cmp     w1, #0
  85         mov     w0, #1
  86         beq     exit
  87         mov     w0, w1
  88 exit
  89         // use br not ret, as ret is guaranteed to mispredict
  90         br      x30
  91
  92 ASM_FUNCTION_REMOVE_IF_UNREFERENCED
  93
  94   END
  95