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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 _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
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