rt-thread/libcpu/risc-v/virt64/startup_gcc.S

95 lines
1.7 KiB
ArmAsm

/*
* Copyright (c) 2006-2018, 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
* 2020/6/12 Xim Port to QEMU and remove SMP support
*/
#define SSTATUS_FS 0x00006000U /* initial state of FPU, clear to disable */
#include <cpuport.h>
boot_hartid: .int
.global boot_hartid
.global _start
.section ".start", "ax"
_start:
j 1f
.word 0xdeadbeef
.align 3
.global g_wake_up
g_wake_up:
.dword 1
.dword 0
1:
# save hartid
la t0, boot_hartid # global varible rt_boot_hartid
mv t1, a0 # get hartid in S-mode frome a0 register
sw t1, (t0) # store t1 register low 4 bits in memory address which is stored in t0
# clear Interrupt Registers
csrw sie, 0
csrw sip, 0
# set Trap Vector Base Address Register
la t0, trap_entry
csrw stvec, 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 disable FPU */
li t0, SSTATUS_FS
csrc sstatus, t0
li t0, 0x40000 // SUM in sstatus
csrs sstatus, t0
.option push
.option norelax
la gp, __global_pointer$
.option pop
// removed SMP support here
la sp, __stack_start__
li t0, __STACKSIZE__
add sp, sp, t0
/**
* sscratch is always zero on kernel mode
*/
csrw sscratch, zero
j primary_cpu_entry