278 lines
5.5 KiB
ArmAsm
278 lines
5.5 KiB
ArmAsm
/*
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* Startup Code for MIPS32 CPU-core
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*
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* Copyright (c) 2003 Wolfgang Denk <wd@denx.de>
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*
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* See file CREDITS for list of people who contributed to this
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* project.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of
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* the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
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* MA 02111-1307 USA
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*/
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#include <asm-offsets.h>
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#include <config.h>
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#include <asm/regdef.h>
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#include <asm/mipsregs.h>
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#ifndef CONFIG_SYS_MIPS_CACHE_MODE
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#define CONFIG_SYS_MIPS_CACHE_MODE CONF_CM_CACHABLE_NONCOHERENT
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#endif
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/*
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* For the moment disable interrupts, mark the kernel mode and
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* set ST0_KX so that the CPU does not spit fire when using
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* 64-bit addresses.
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*/
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.macro setup_c0_status set clr
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.set push
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mfc0 t0, CP0_STATUS
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or t0, ST0_CU0 | \set | 0x1f | \clr
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xor t0, 0x1f | \clr
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mtc0 t0, CP0_STATUS
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.set noreorder
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sll zero, 3 # ehb
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.set pop
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.endm
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.set noreorder
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.globl _start
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.text
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_start:
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/* U-boot entry point */
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b reset
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nop
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.org 0x10
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#ifdef CONFIG_SYS_XWAY_EBU_BOOTCFG
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/*
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* Almost all Lantiq XWAY SoC devices have an external bus unit (EBU) to
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* access external NOR flashes. If the board boots from NOR flash the
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* internal BootROM does a blind read at address 0xB0000010 to read the
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* initial configuration for that EBU in order to access the flash
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* device with correct parameters. This config option is board-specific.
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*/
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.word CONFIG_SYS_XWAY_EBU_BOOTCFG
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.word 0x0
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#endif
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.org 0x200
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/* TLB refill, 32 bit task */
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1: b 1b
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nop
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.org 0x280
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/* XTLB refill, 64 bit task */
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1: b 1b
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nop
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.org 0x300
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/* Cache error exception */
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1: b 1b
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nop
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.org 0x380
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/* General exception */
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1: b 1b
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nop
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.org 0x400
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/* Catch interrupt exceptions */
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1: b 1b
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nop
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.org 0x480
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/* EJTAG debug exception */
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1: b 1b
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nop
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.align 4
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reset:
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/* Clear watch registers */
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mtc0 zero, CP0_WATCHLO
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mtc0 zero, CP0_WATCHHI
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/* WP(Watch Pending), SW0/1 should be cleared */
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mtc0 zero, CP0_CAUSE
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setup_c0_status 0 0
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/* Init Timer */
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mtc0 zero, CP0_COUNT
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mtc0 zero, CP0_COMPARE
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#ifndef CONFIG_SKIP_LOWLEVEL_INIT
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/* CONFIG0 register */
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li t0, CONF_CM_UNCACHED
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mtc0 t0, CP0_CONFIG
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#endif
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/* Initialize $gp */
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bal 1f
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nop
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.word _gp
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1:
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lw gp, 0(ra)
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#ifndef CONFIG_SKIP_LOWLEVEL_INIT
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/* Initialize any external memory */
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la t9, lowlevel_init
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jalr t9
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nop
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/* Initialize caches... */
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la t9, mips_cache_reset
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jalr t9
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nop
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/* ... and enable them */
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li t0, CONFIG_SYS_MIPS_CACHE_MODE
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mtc0 t0, CP0_CONFIG
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#endif
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/* Set up temporary stack */
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li sp, CONFIG_SYS_SDRAM_BASE + CONFIG_SYS_INIT_SP_OFFSET
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la t9, board_init_f
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jr t9
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nop
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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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* a0 = addr_sp
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* a1 = gd
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* a2 = destination address
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*/
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.globl relocate_code
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.ent relocate_code
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relocate_code:
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move sp, a0 # set new stack pointer
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move s0, a1 # save gd in s0
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move s2, a2 # save destination address in s2
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li t0, CONFIG_SYS_MONITOR_BASE
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sub s1, s2, t0 # s1 <-- relocation offset
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la t3, in_ram
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lw t2, -12(t3) # t2 <-- __image_copy_end
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move t1, a2
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add gp, s1 # adjust gp
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/*
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* t0 = source address
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* t1 = target address
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* t2 = source end address
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*/
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1:
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lw t3, 0(t0)
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sw t3, 0(t1)
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addu t0, 4
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blt t0, t2, 1b
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addu t1, 4
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/* If caches were enabled, we would have to flush them here. */
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sub a1, t1, s2 # a1 <-- size
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la t9, flush_cache
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jalr t9
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move a0, s2 # a0 <-- destination address
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/* Jump to where we've relocated ourselves */
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addi t0, s2, in_ram - _start
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jr t0
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nop
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.word __rel_dyn_end
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.word __rel_dyn_start
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.word __image_copy_end
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.word _GLOBAL_OFFSET_TABLE_
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.word num_got_entries
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in_ram:
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/*
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* Now we want to update GOT.
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*
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* GOT[0] is reserved. GOT[1] is also reserved for the dynamic object
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* generated by GNU ld. Skip these reserved entries from relocation.
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*/
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lw t3, -4(t0) # t3 <-- num_got_entries
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lw t4, -8(t0) # t4 <-- _GLOBAL_OFFSET_TABLE_
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add t4, s1 # t4 now holds relocated _G_O_T_
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addi t4, t4, 8 # skipping first two entries
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li t2, 2
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1:
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lw t1, 0(t4)
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beqz t1, 2f
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add t1, s1
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sw t1, 0(t4)
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2:
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addi t2, 1
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blt t2, t3, 1b
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addi t4, 4
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/* Update dynamic relocations */
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lw t1, -16(t0) # t1 <-- __rel_dyn_start
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lw t2, -20(t0) # t2 <-- __rel_dyn_end
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b 2f # skip first reserved entry
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addi t1, 8
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1:
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lw t3, -4(t1) # t3 <-- relocation info
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sub t3, 3
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bnez t3, 2f # skip non R_MIPS_REL32 entries
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nop
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lw t3, -8(t1) # t3 <-- location to fix up in FLASH
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lw t4, 0(t3) # t4 <-- original pointer
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add t4, s1 # t4 <-- adjusted pointer
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add t3, s1 # t3 <-- location to fix up in RAM
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sw t4, 0(t3)
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2:
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blt t1, t2, 1b
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addi t1, 8 # each rel.dyn entry is 8 bytes
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/*
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* Clear BSS
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*
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* GOT is now relocated. Thus __bss_start and __bss_end can be
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* accessed directly via $gp.
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*/
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la t1, __bss_start # t1 <-- __bss_start
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la t2, __bss_end # t2 <-- __bss_end
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1:
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sw zero, 0(t1)
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blt t1, t2, 1b
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addi t1, 4
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move a0, s0 # a0 <-- gd
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la t9, board_init_r
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jr t9
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move a1, s2
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.end relocate_code
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