.section .text.boot
.global _start
.global _stack_top

_start:
    // load stackpointer
    la sp, _stack_top

    // Copy .data section from flash to RAM
    la a0, _data_load   // Source address in flash
    la a1, _data_start  // Destination address in RAM
    la a2, _data_end

    // Skip if no data to copy
    beq a1, a2, init_bss
copy_data:
    lw t0, 0(a0)        // Load word from flash
    sw t0, 0(a1)        // Store to RAM
    addi a0, a0, 4      // Increment source
    addi a1, a1, 4      // Increment destination
    bltu a1, a2, copy_data

init_bss:
    // Clear .bss section
    la a0, _bss_start
    la a1, _bss_end

    // Skip if no bss to clear
    beq a0, a1, init_done
clear_bss:
    sw zero, 0(a0)      // Store zero
    addi a0, a0, 4      // Increment address
    bltu a0, a1, clear_bss

init_done:
    // Jump to main function
    call main

1:  // Infinite loop if main returns
    j 1b

.end