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# XSTORMY16 startup code

# Interrupt vectors at 0x8000.

        .section .int_vec,"ax"

        .global _start

        .align 1

_start:

        ;; Reset, watchdog timer interrupt

        jmpf _int_reset

        ;; base timer interrupt

        jmpf _int_basetimer

        ;; timer 0

        jmpf _int_timer0

        ;; timer 1

        jmpf _int_timer1

        ;; SIO0 interrupt

        jmpf _int_sio0

        ;; SIO1 interrupt

        jmpf _int_sio1

        ;; port0 interrupt

        jmpf _int_port0

        ;; port1 interrupt

        jmpf _int_port1

# Reset code, set up memory and call main.

        .section        .rodata

2:      .word   __rdata

        .text

_int_reset:

        ;; Set up the stack pointer.

        mov r0,#__stack

        bz  r0,#0,0f

        mov sp,r0

0:

        ;; Zero the data space

        mov r0,#_edata

        mov r1,#_end

        mov r2,#0

0:       mov.w (r0++),r2

        blt r0,r1,0b

        ;; Copy data from ROM into RAM.  ROM area may be above 64k,

        ;; but RAM may not.

        mov r1,#__data

        mov r3,#_edata

        mov r4,#2b

        mov.w r0,(r4++)

        mov.w r2,(r4)

        mov r8,r2

        ;; If _data == _rdata there's no need to copy anything.

        bnz r0,r1,0f

        bz r2,#0,1f

0:       movf.w r2,(r0++)

        bnz r0,#0,2f

        add r8,#1

2:      mov.w (r1++),r2

        blt r1,r3,0b

1:

        ;; Call hardware init routine

        callf _hwinit

        ;; Call initialization routines

        callf _init

        ;; Set up fini routines to be called from exit

        mov r2,#@fptr(_fini)

        callf atexit

        ;; Call main() with empty argc/argv/envp

        mov r2,#0

        mov r3,#0

        mov r4,#0

        callf main

        ;; Exit.

        callf exit

        ;; Should never reach this code.

        halt

1:      .size _int_reset,1b-_int_reset

# Stub interrupt routines.

        .globl _int_timer0

        .weak _int_timer0

        .globl _int_timer1

        .weak _int_timer1

        .globl _int_sio0

        .weak _int_sio0

        .globl _int_sio1

        .weak _int_sio1

        .globl _int_port0

        .weak _int_port0

        .globl _int_port1

        .weak _int_port1

        .globl _int_basetimer

        .weak _int_basetimer

_int_timer0:

_int_timer1:

_int_sio0:

_int_sio1:

_int_port0:

_int_port1:

_int_basetimer:

        iret

1:      .size _int_timer0,1b-_int_timer0

# Stub hardware init

        .globl _hwinit

        .weak _hwinit

_hwinit:

        ret

1:      .size _int_hwinit,1b-_int_hwinit

# The first word in .data has address 0, so it's not a good

# idea to use it as its address conflicts with NULL.

# Place a HALT instruction there to try to catch NULL pointer

# dereferences.

        .data

        halt