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[/] [neorv32/] [trunk/] [sw/] [lib/] [source/] [neorv32_cpu.c] - Diff between revs 16 and 18

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Rev 16 Rev 18
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/**********************************************************************//**
/**********************************************************************//**
 * Switch from privilege mode MACHINE to privilege mode USER.
 * Switch from privilege mode MACHINE to privilege mode USER.
 *
 *
 * @note This function requires the U extension to be implemented.
 * @note This function requires the U extension to be implemented.
 * @note Maybe you should do a fencei after this.
 * @note Maybe you should do a fence.i after this.
 **************************************************************************/
 **************************************************************************/
void __attribute__((naked)) neorv32_cpu_goto_user_mode(void) {
void __attribute__((naked)) neorv32_cpu_goto_user_mode(void) {
 
 
  register uint32_t mask = (1<<CPU_MSTATUS_MPP_H) | (1<<CPU_MSTATUS_MPP_L);
  register uint32_t mask = (1<<CPU_MSTATUS_MPP_H) | (1<<CPU_MSTATUS_MPP_L);
  mask = ~mask;
 
  asm volatile ("csrrc zero, mstatus, %[input_j]" :  : [input_j] "r" (mask));
  asm volatile ("csrrc zero, mstatus, %[input_j]" :  : [input_j] "r" (mask));
 
 
  // return and switch to user mode
  // return switching to user mode
  asm volatile ("csrw mepc, ra");
  asm volatile ("csrw mepc, ra");
  asm volatile ("mret");
  asm volatile ("mret");
}
}
 
 
 
 
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