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/* c-isr library stuff of Andes NDS32 cpu for GNU compiler
Copyright (C) 2012-2021 Free Software Foundation, Inc.
Contributed by Andes Technology Corporation.
This file is part of GCC.
GCC is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published
by the Free Software Foundation; either version 3, or (at your
option) any later version.
GCC is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
License for more details.
Under Section 7 of GPL version 3, you are granted additional
permissions described in the GCC Runtime Library Exception, version
3.1, as published by the Free Software Foundation.
You should have received a copy of the GNU General Public License and
a copy of the GCC Runtime Library Exception along with this program;
see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
<>. */
.section .nds32_isr, "ax" /* Put it in the section of 1st level handler. */
.align 1
.weak _SDA_BASE_ /* For reset handler only. */
.weak _nds32_init_mem /* User defined memory initialization function. */
.globl _start
.globl _nds32_reset
.type _nds32_reset, @function
/* Handle NMI and warm boot if any of them exists. */
beqz $sp, 1f /* Reset, NMI or warm boot? */
/* Either NMI or warm boot; save all regs. */
/* Preserve registers for context-switching. */
/* For 16-reg mode. */
smw.adm $r0, [$sp], $r10, #0x0
smw.adm $r15, [$sp], $r15, #0xf
/* For 32-reg mode. */
smw.adm $r0, [$sp], $r27, #0xf
#if __NDS32_EXT_IFC__
mfusr $r1, $IFC_LP
smw.adm $r1, [$sp], $r2, #0x0 /* Save extra $r2 to keep stack 8-byte alignment. */
la $gp, _SDA_BASE_ /* Init GP for small data access. */
move $r0, $sp /* Init parameter. */
mfsr $r1, $ITYPE /* Check ITYPE for NMI or warm boot. */
andi $r1, $r1, #0xf
addi $r1, $r1, #-1
beqz $r1, 2f /* Warm boot if true. */
l.w $r15, _nds32_nmih /* Load NMI handler. */
j 3f
l.w $r15, _nds32_wrh /* Load warm boot handler. */
beqz $r15, 1f /* If no handler, do cold boot. */
jral $r15 /* Call handler. */
bnez $r0, 1f /* If fail to resume, do cold boot. */
/* Restore registers for context-switching. */
#if __NDS32_EXT_IFC__
lmw.bim $r1, [$sp], $r2, #0x0 /* Restore extra $r2 to keep stack 8-byte alignment. */
mtusr $r1, $IFC_LP
/* For 16-reg mode. */
lmw.bim $r15, [$sp], $r15, #0xf
lmw.bim $r0, [$sp], $r10, #0x0
/* For 32-reg mode. */
lmw.bim $r0, [$sp], $r27, #0xf
iret /* Resume operation. */
1: /* Cold boot. */
/* With vector ID feature for v3 architecture, default vector size is 4-byte. */
/* Set IVB.ESZ = 0 (vector table entry size = 4 bytes) */
mfsr $r0, $IVB
li $r1, #0xc000
or $r0, $r0, $r1
xor $r0, $r0, $r1
mtsr $r0, $IVB
/* There is no vector ID feature, so the vector size must be 16-byte. */
/* Set IVB.ESZ = 1 (vector table entry size = 16 bytes) */
mfsr $r0, $IVB
li $r1, #0xffff3fff
and $r0, $r0, $r1
ori $r0, $r0, #0x4000
mtsr $r0, $IVB
la $gp, _SDA_BASE_ /* Init $gp. */
la $sp, _stack /* Init $sp. */
#if __NDS32_EXT_EX9__
/* Initialization for Instruction Table Base (ITB).
The symbol _ITB_BASE_ is determined by Linker.
Set $ITB only if MSC_CFG.EIT (cr4.b'24) is set. */
mfsr $r0, $MSC_CFG
srli $r0, $r0, 24
andi $r0, $r0, 0x1
beqz $r0, 4f /* Fall through ? */
la $r0, _ITB_BASE_
mtusr $r0, $ITB
#if __NDS32_EXT_FPU_SP__ || __NDS32_EXT_FPU_DP__
/* Initialize FPU
Set FUCOP_CTL.CP0EN (fucpr.b'0). */
mfsr $r0, $FUCOP_CTL
ori $r0, $r0, 0x1
mtsr $r0, $FUCOP_CTL
/* According to [bugzilla #9425], set flush-to-zero mode.
That is, set $FPCSR.DNZ(b'12) = 1. */
ori $r0, $r0, 0x1000
/* Call DRAM init. _nds32_init_mem may written by C language. */
la $r15, _nds32_init_mem
beqz $r15, 6f
jral $r15
l.w $r15, _nds32_jmptbl_00 /* Load reset handler. */
jral $r15
/* Reset handler() should never return in a RTOS or non-OS system.
In case it does return, an exception will be generated.
This exception will be caught either by default break handler or by EDM.
Default break handle may just do an infinite loop.
EDM will notify GDB and GDB will regain control when the ID is 0x7fff. */
break #0x7fff
.size _nds32_reset, .-_nds32_reset