Subversion Repositories sardmips

/*
 * Starting point for everything (bootstrap)
 *
 * Initializes the stack pointer and jumps to main().
 */

#include "regdef.h"

        .text
        .align  2
        .globl  _start
        .ent    _start
_start:
        .set noreorder

        j       reset_handler
        nop
        
        j       handling_exception
        nop

        
reset_handler:
        /* Setup stack pointer */
        la      sp, _sp
      
        /* Clear bss */
        la      t0, 0x00000000      /* First address */
        la      t1, _end        /* Last  address */
        
        mfc0 k0, $12
        add k0, k0, 3
        mtc0 k0, $12
        
        
        jal     main
        nop
        j loop
        nop
        
handling_exception:     
        nop
        mfc0 k0, $13
        mfc0 k1, $14
        
        srl k0, k0, 2
        andi k0, k0, 0x1F
        
        beq k0, $0, handling_interrupt
        nop
        
        add $11, $0, $0
        addiu $11, k1, 4
        mtc0 $11, $14
        eret
        nop
        
        
handling_interrupt:
        nop
        eret
        nop

        /* Run endless loop when the program terminates */
loop:
        j       loop

        .set    reorder
        .end    _start