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#-------------------------------------------------------------------------------

# startup.s -- C startup code common to all C programs.

#

# This code does the following:

# 1.- Initialize the stack at the end of the bss area

# 2.- Clear the bss area

# 3.- Move the data section from FLASH to RAM (if applicable)

# 4.- Call main()

# 5.- Freeze in endless loop after main() returns, if it does

#

# The code does not initialize the caches or the hardware and does not include

# the reset or trap vectors.

#

# This code was inherited from OpenCores' Plasma project.

#-------------------------------------------------------------------------------

    # The stack size can be defined from the assembler command line

    # FIXME should use info from the link script

    .ifndef STACK_SIZE

    .set    STACK_SIZE,         1024        # by default, reserve 1KB

    .endif

    # Reserve space for regular stack (BSS segment)

    .comm init_stack, STACK_SIZE

    .text

    .align 2

    .global entry

    .ent    entry

entry:

    .set noreorder

    # (The linker script defined these symbols)

    la      $gp, _gp                # initialize global pointer

    la      $5, __bss_start         # $5 = .sbss_start

    la      $4, _end                # $2 = .bss_end

    la      $sp, init_stack+STACK_SIZE-24 #initialize stack pointer

    # Clear BSS area

$BSS_CLEAR:

    sw      $0, 0($5)

    slt     $3, $5, $4

    bnez    $3, $BSS_CLEAR

    addiu   $5, $5, 4

    # Move data section image from flash to RAM, if necessary.

    la      $a0,data_start

    la      $a1,data_load_start

    beq     $a1,$a0,move_data_section_done

    nop

    la      $s0,data_size

    beqz    $s0,move_data_section_done

    nop

move_data_section_loop:

    lw      $t0,0($a1)

    addiu   $a1,$a1,4

    sw      $t0,0($a0)

    addiu   $a0,$a0,4

    bnez    $s0,move_data_section_loop

    addiu   $s0,$s0,-4

move_data_section_done:

    jal     main                    # init done; call main()

    nop

$L1:

    j       $L1

    nop

    .end     entry