292 lines
6.3 KiB
ArmAsm
292 lines
6.3 KiB
ArmAsm
/*
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* Startup Code for RISC-V Core
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*
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* Copyright (c) 2017 Microsemi Corporation.
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* Copyright (c) 2017 Padmarao Begari <Padmarao.Begari@microsemi.com>
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*
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* Copyright (C) 2017 Andes Technology Corporation
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* Rick Chen, Andes Technology Corporation <rick@andestech.com>
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*
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* SPDX-License-Identifier: GPL-2.0+
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*/
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#include <asm-offsets.h>
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#include <config.h>
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#include <common.h>
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#include <elf.h>
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#include <asm/encoding.h>
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#ifdef CONFIG_32BIT
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#define LREG lw
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#define SREG sw
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#define REGBYTES 4
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#define RELOC_TYPE R_RISCV_32
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#define SYM_INDEX 0x8
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#define SYM_SIZE 0x10
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#else
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#define LREG ld
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#define SREG sd
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#define REGBYTES 8
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#define RELOC_TYPE R_RISCV_64
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#define SYM_INDEX 0x20
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#define SYM_SIZE 0x18
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#endif
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.section .text
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.globl _start
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_start:
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j handle_reset
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nmi_vector:
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j nmi_vector
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trap_vector:
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j trap_entry
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.global trap_entry
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handle_reset:
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la t0, trap_entry
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csrw mtvec, t0
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csrwi mstatus, 0
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csrwi mie, 0
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/*
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* Do CPU critical regs init only at reboot,
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* not when booting from ram
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*/
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#ifdef CONFIG_INIT_CRITICAL
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jal cpu_init_crit /* Do CPU critical regs init */
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#endif
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/*
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* Set stackpointer in internal/ex RAM to call board_init_f
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*/
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call_board_init_f:
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li t0, -16
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li t1, CONFIG_SYS_INIT_SP_ADDR
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and sp, t1, t0 /* force 16 byte alignment */
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#ifdef CONFIG_DEBUG_UART
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jal debug_uart_init
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#endif
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call_board_init_f_0:
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mv a0, sp
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jal board_init_f_alloc_reserve
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mv sp, a0
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jal board_init_f_init_reserve
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mv a0, zero /* a0 <-- boot_flags = 0 */
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la t5, board_init_f
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jr t5 /* jump to board_init_f() */
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/*
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* void relocate_code (addr_sp, gd, addr_moni)
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*
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* This "function" does not return, instead it continues in RAM
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* after relocating the monitor code.
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*
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*/
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.globl relocate_code
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relocate_code:
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mv s2, a0 /* save addr_sp */
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mv s3, a1 /* save addr of gd */
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mv s4, a2 /* save addr of destination */
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/*
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*Set up the stack
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*/
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stack_setup:
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mv sp, s2
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la t0, _start
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sub t6, s4, t0 /* t6 <- relocation offset */
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beq t0, s4, clear_bss /* skip relocation */
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mv t1, s4 /* t1 <- scratch for copy_loop */
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la t3, __bss_start
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sub t3, t3, t0 /* t3 <- __bss_start_ofs */
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add t2, t0, t3 /* t2 <- source end address */
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copy_loop:
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LREG t5, 0(t0)
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addi t0, t0, REGBYTES
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SREG t5, 0(t1)
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addi t1, t1, REGBYTES
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blt t0, t2, copy_loop
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/*
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* Update dynamic relocations after board_init_f
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*/
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fix_rela_dyn:
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la t1, __rel_dyn_start
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la t2, __rel_dyn_end
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beq t1, t2, clear_bss
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add t1, t1, t6 /* t1 <- rela_dyn_start in RAM */
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add t2, t2, t6 /* t2 <- rela_dyn_end in RAM */
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/*
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* skip first reserved entry: address, type, addend
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*/
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bne t1, t2, 7f
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6:
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LREG t5, -(REGBYTES*2)(t1) /* t5 <-- relocation info:type */
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li t3, R_RISCV_RELATIVE /* reloc type R_RISCV_RELATIVE */
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bne t5, t3, 8f /* skip non-RISCV_RELOC entries */
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LREG t3, -(REGBYTES*3)(t1)
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LREG t5, -(REGBYTES)(t1) /* t5 <-- addend */
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add t5, t5, t6 /* t5 <-- location to fix up in RAM */
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add t3, t3, t6 /* t3 <-- location to fix up in RAM */
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SREG t5, 0(t3)
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7:
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addi t1, t1, (REGBYTES*3)
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ble t1, t2, 6b
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8:
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la t4, __dyn_sym_start
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add t4, t4, t6
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9:
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LREG t5, -(REGBYTES*2)(t1) /* t5 <-- relocation info:type */
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srli t0, t5, SYM_INDEX /* t0 <--- sym table index */
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andi t5, t5, 0xFF /* t5 <--- relocation type */
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li t3, RELOC_TYPE
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bne t5, t3, 10f /* skip non-addned entries */
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LREG t3, -(REGBYTES*3)(t1)
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li t5, SYM_SIZE
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mul t0, t0, t5
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add s1, t4, t0
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LREG t5, REGBYTES(s1)
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add t5, t5, t6 /* t5 <-- location to fix up in RAM */
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add t3, t3, t6 /* t3 <-- location to fix up in RAM */
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SREG t5, 0(t3)
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10:
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addi t1, t1, (REGBYTES*3)
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ble t1, t2, 9b
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/*
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* trap update
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*/
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la t0, trap_entry
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add t0, t0, t6
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csrw mtvec, t0
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clear_bss:
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la t0, __bss_start /* t0 <- rel __bss_start in FLASH */
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add t0, t0, t6 /* t0 <- rel __bss_start in RAM */
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la t1, __bss_end /* t1 <- rel __bss_end in FLASH */
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add t1, t1, t6 /* t1 <- rel __bss_end in RAM */
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li t2, 0x00000000 /* clear */
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beq t0, t1, call_board_init_r
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clbss_l:
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SREG t2, 0(t0) /* clear loop... */
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addi t0, t0, REGBYTES
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bne t0, t1, clbss_l
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/*
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* We are done. Do not return, instead branch to second part of board
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* initialization, now running from RAM.
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*/
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call_board_init_r:
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la t0, board_init_r
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mv t4, t0 /* offset of board_init_r() */
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add t4, t4, t6 /* real address of board_init_r() */
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/*
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* setup parameters for board_init_r
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*/
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mv a0, s3 /* gd_t */
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mv a1, s4 /* dest_addr */
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/*
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* jump to it ...
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*/
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jr t4 /* jump to board_init_r() */
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/*
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* trap entry
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*/
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trap_entry:
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addi sp, sp, -32*REGBYTES
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SREG x1, 1*REGBYTES(sp)
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SREG x2, 2*REGBYTES(sp)
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SREG x3, 3*REGBYTES(sp)
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SREG x4, 4*REGBYTES(sp)
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SREG x5, 5*REGBYTES(sp)
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SREG x6, 6*REGBYTES(sp)
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SREG x7, 7*REGBYTES(sp)
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SREG x8, 8*REGBYTES(sp)
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SREG x9, 9*REGBYTES(sp)
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SREG x10, 10*REGBYTES(sp)
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SREG x11, 11*REGBYTES(sp)
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SREG x12, 12*REGBYTES(sp)
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SREG x13, 13*REGBYTES(sp)
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SREG x14, 14*REGBYTES(sp)
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SREG x15, 15*REGBYTES(sp)
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SREG x16, 16*REGBYTES(sp)
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SREG x17, 17*REGBYTES(sp)
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SREG x18, 18*REGBYTES(sp)
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SREG x19, 19*REGBYTES(sp)
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SREG x20, 20*REGBYTES(sp)
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SREG x21, 21*REGBYTES(sp)
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SREG x22, 22*REGBYTES(sp)
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SREG x23, 23*REGBYTES(sp)
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SREG x24, 24*REGBYTES(sp)
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SREG x25, 25*REGBYTES(sp)
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SREG x26, 26*REGBYTES(sp)
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SREG x27, 27*REGBYTES(sp)
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SREG x28, 28*REGBYTES(sp)
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SREG x29, 29*REGBYTES(sp)
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SREG x30, 30*REGBYTES(sp)
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SREG x31, 31*REGBYTES(sp)
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csrr a0, mcause
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csrr a1, mepc
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mv a2, sp
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jal handle_trap
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csrw mepc, a0
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/*
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* Remain in M-mode after mret
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*/
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li t0, MSTATUS_MPP
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csrs mstatus, t0
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LREG x1, 1*REGBYTES(sp)
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LREG x2, 2*REGBYTES(sp)
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LREG x3, 3*REGBYTES(sp)
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LREG x4, 4*REGBYTES(sp)
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LREG x5, 5*REGBYTES(sp)
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LREG x6, 6*REGBYTES(sp)
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LREG x7, 7*REGBYTES(sp)
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LREG x8, 8*REGBYTES(sp)
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LREG x9, 9*REGBYTES(sp)
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LREG x10, 10*REGBYTES(sp)
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LREG x11, 11*REGBYTES(sp)
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LREG x12, 12*REGBYTES(sp)
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LREG x13, 13*REGBYTES(sp)
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LREG x14, 14*REGBYTES(sp)
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LREG x15, 15*REGBYTES(sp)
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LREG x16, 16*REGBYTES(sp)
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LREG x17, 17*REGBYTES(sp)
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LREG x18, 18*REGBYTES(sp)
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LREG x19, 19*REGBYTES(sp)
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LREG x20, 20*REGBYTES(sp)
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LREG x21, 21*REGBYTES(sp)
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LREG x22, 22*REGBYTES(sp)
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LREG x23, 23*REGBYTES(sp)
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LREG x24, 24*REGBYTES(sp)
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LREG x25, 25*REGBYTES(sp)
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LREG x26, 26*REGBYTES(sp)
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LREG x27, 27*REGBYTES(sp)
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LREG x28, 28*REGBYTES(sp)
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LREG x29, 29*REGBYTES(sp)
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LREG x30, 30*REGBYTES(sp)
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LREG x31, 31*REGBYTES(sp)
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addi sp, sp, 32*REGBYTES
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mret
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#ifdef CONFIG_INIT_CRITICAL
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cpu_init_crit:
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ret
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#endif
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