src/rt/arch/arm/context.cpp

   1 // xfail-license
   2
   3 #include "context.h"
   4 #include "../../rust_globals.h"
   5
   6 extern "C" void CDECL swap_registers(registers_t *oregs,
   7                                      registers_t *regs)
   8 asm ("swap_registers");
   9
  10 context::context()
  11 {
  12     assert((void*)&regs == (void*)this);
  13     memset(&regs, 0, sizeof(regs));
  14 }
  15
  16 void context::swap(context &out)
  17 {
  18     swap_registers(&out.regs, &regs);
  19 }
  20
  21 void context::call(void *f, void *arg, void *stack)
  22 {
  23   // Get the current context, which we will then modify to call the
  24   // given function.
  25   swap(*this);
  26
  27   // set up the stack
  28   uint32_t *sp = ( uint32_t *)stack;
  29   sp = align_down(sp);
  30   // The final return address. 0 indicates the bottom of the stack
  31   // sp of arm eabi is 8-byte aligned
  32   sp -= 2;
  33   *sp = 0;
  34
  35   regs.data[0] = ( uint32_t )arg; // r0
  36   regs.data[13] = ( uint32_t )sp; //#52 sp, r13
  37   regs.data[14] = ( uint32_t )f;  //#60 pc, r15 --> lr,
  38   // Last base pointer on the stack should be 0
  39 }