crt0.s

来自「ADC图形图像例子」· S 代码 · 共 65 行

##==============================================================================
##      crt0.S
##      SE3208 startup code
##==============================================================================
## Copyright (c) 1995, 1996, 1997, 1998 Cygnus Solutions
## The authors hereby grant permission to use, copy, modify, distribute,
## and license this software and its documentation for any purpose, provided
## that existing copyright notices are retained in all copies and that this
## notice is included verbatim in any distributions. No written agreement,
## license, or royalty fee is required for any of the authorized uses.
## Modifications to this software may be copyrighted by their authors
## and need not follow the licensing terms described here, provided that
## the new terms are clearly indicated on the first page of each file where
## they apply.
##==============================================================================

    .file   "crt0.S"
    .section .text
    .global _start
_start:
/* initialize stack pointer : move unline from GPR upline*/
	ldi     _stack-8, %r3   # Load up the stack pointer and allocate stack=0x020f:ffff
    lea     (%r3),    %sp   # our current frame.

###################################################################
# PIN MUX SET
###################################################################
   ldi     0x01800018, %R6     # Pin Mux Control Register 1
    ldi     0x00000400, %R7
    st      %R7, (%R6,0)

    ldi     0x0180001C, %R6     # Pin Mux Control Register 2
    ldi     0x00000000, %R7
    st      %R7, (%R6,0)
	
###################################################################
# < LED ON/OFF LOOP >
###################################################################

    ldi     0x01802000, %R6     # Pin Mux Control Register 1
    ldi     0x00000000, %R7
    st      %R7, (%R6,0)
	
.LEDLOOP:
    ldi     0x01802004, %R6
    ldi     0x08000000, %R7     #LED On(PIO27)
    st      %R7, (%R6,0)

    ldi     0x0003ffff, %r0
.DELAYLOOP1:
    sub     %r0, 1, %r0
    jnz     .DELAYLOOP1

    ldi     0x01802004, %R6
    ldi     0x00000000, %R7     #LED Off(PIO27)
    st      %R7, (%R6,0)

    ldi     0x0003ffff , %r0
.DELAYLOOP2:
    sub     %r0, 1, %r0
    jnz     .DELAYLOOP2

    jp      .LEDLOOP