newlib-cygwin/libgloss/iq2000/crt0.S

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2003-06-07 00:07:57 +08:00
##==============================================================================
##
## crt0.S
##
## IQ2000 startup code
##
##==============================================================================
##
## Copyright (c) 2000, Cygnus Solutions, A Red Hat Company
##
## 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"
##------------------------------------------------------------------------------
## Startup code
.section .text
.global _start
_start:
lui %29,%hi(__stack)
ori %29,%29,%lo(__stack)
lui %24,%hi(_edata) # get start of bss
ori %24,%24,%lo(_edata)
lui %25,%hi(_end) # get end of bss
ori %25,%25,%lo(_end)
beq %24,%25,.L0 # check if end and start are the same
# do nothing if no bss
.L1:
sb %0,0(%24) # clear a byte and bump pointer
addi %24,%24,1
bne %24,%25,.L1
nop
.L0:
jal _main # call _main to run ctors/dtors
nop
xor %4,%4,%4
jal main # call main program
xor %5,%5,%5
jal exit # all done, no need to return or
or %4,%0,%2 # exit with main's return value