rt-thread/libcpu/risc-v/k210/startup_gcc.S

/*
 * Copyright (c) 2006-2022, RT-Thread Development Team
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * Change Logs:
 * Date           Author       Notes
 * 2018/10/01     Bernard      The first version
 * 2018/12/27     Jesven       Add SMP support
 */

#define MSTATUS_FS      0x00006000U /* initial state of FPU     */
#include <cpuport.h>

  .global   _start
  .section ".start", "ax"
_start:
  j 1f
  .word 0xdeadbeef
  .align 3
  .global g_wake_up
  g_wake_up:
      .dword 1
      .dword 0
1:
  csrw mideleg, 0
  csrw medeleg, 0
  csrw mie, 0
  csrw mip, 0
  la t0, trap_entry
  csrw mtvec, t0

  li x1, 0
  li x2, 0
  li x3, 0
  li x4, 0
  li x5, 0
  li x6, 0
  li x7, 0
  li x8, 0
  li x9, 0
  li x10,0
  li x11,0
  li x12,0
  li x13,0
  li x14,0
  li x15,0
  li x16,0
  li x17,0
  li x18,0
  li x19,0
  li x20,0
  li x21,0
  li x22,0
  li x23,0
  li x24,0
  li x25,0
  li x26,0
  li x27,0
  li x28,0
  li x29,0
  li x30,0
  li x31,0

  /* set to initial state of FPU and disable interrupt */
  li t0, MSTATUS_FS
  csrs mstatus, t0

  fssr    x0
  fmv.w.x f0, x0
  fmv.w.x f1, x0
  fmv.w.x f2, x0
  fmv.w.x f3, x0
  fmv.w.x f4, x0
  fmv.w.x f5, x0
  fmv.w.x f6, x0
  fmv.w.x f7, x0
  fmv.w.x f8, x0
  fmv.w.x f9, x0
  fmv.w.x f10,x0
  fmv.w.x f11,x0
  fmv.w.x f12,x0
  fmv.w.x f13,x0
  fmv.w.x f14,x0
  fmv.w.x f15,x0
  fmv.w.x f16,x0
  fmv.w.x f17,x0
  fmv.w.x f18,x0
  fmv.w.x f19,x0
  fmv.w.x f20,x0
  fmv.w.x f21,x0
  fmv.w.x f22,x0
  fmv.w.x f23,x0
  fmv.w.x f24,x0
  fmv.w.x f25,x0
  fmv.w.x f26,x0
  fmv.w.x f27,x0
  fmv.w.x f28,x0
  fmv.w.x f29,x0
  fmv.w.x f30,x0
  fmv.w.x f31,x0

.option push
.option norelax
  la gp, __global_pointer$
.option pop

  /* get cpu id */
  csrr a0, mhartid

  la   sp, __stack_start__
  addi t1, a0, 1
  li   t2, __STACKSIZE__
  mul  t1, t1, t2
  add  sp, sp, t1 /* sp = (cpuid + 1) * __STACKSIZE__ + __stack_start__ */

  /* other cpu core, jump to cpu entry directly */
  bnez a0, secondary_cpu_entry
  tail primary_cpu_entry

secondary_cpu_entry:
#ifdef RT_USING_SMP
  la a0, secondary_boot_flag
  ld a0, 0(a0)
  li a1, 0xa55a
  beq a0, a1, 1f
#endif
  j secondary_cpu_entry

#ifdef RT_USING_SMP
1:
  tail secondary_cpu_c_start

.data
.global secondary_boot_flag
.align 3
secondary_boot_flag:
    .dword 0
#endif