src/libcompiler_builtins/compiler-rt/lib/builtins/arm/restore_vfp_d8_d15_regs.S

   1 //===-- save_restore_regs.S - Implement save/restore* ---------------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is dual licensed under the MIT and the University of Illinois Open
   6 // Source Licenses. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9
  10 #include "../assembly.h"
  11
  12 //
  13 // When compiling C++ functions that need to handle thrown exceptions the
  14 // compiler is required to save all registers and call __Unwind_SjLj_Register
  15 // in the function prolog.  But when compiling for thumb1, there are
  16 // no instructions to access the floating point registers, so the
  17 // compiler needs to add a call to the helper function _save_vfp_d8_d15_regs
  18 // written in ARM to save the float registers.  In the epilog, the compiler
  19 // must also add a call to __restore_vfp_d8_d15_regs to restore those registers.
  20 //
  21
  22         .text
  23         .syntax unified
  24
  25 //
  26 // Restore registers d8-d15 from stack
  27 //
  28         .p2align 2
  29 DEFINE_COMPILERRT_PRIVATE_FUNCTION(__restore_vfp_d8_d15_regs)
  30         vldmia  sp!, {d8-d15}           // pop registers d8-d15 off stack
  31         bx      lr                      // return to prolog
  32 END_COMPILERRT_FUNCTION(__restore_vfp_d8_d15_regs)
  33
  34 NO_EXEC_STACK_DIRECTIVE
  35