source: trunk/libs/newlib/src/libgloss/xstormy16/crt0.s @ 495

# 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 _hwinit,1b-_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