99 lines
4.0 KiB
ArmAsm
99 lines
4.0 KiB
ArmAsm
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##############################################################################
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# crt0.s -- CR16 default start-up routine #
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# #
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# Copyright (c) 2004 National Semiconductor Corporation #
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# #
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# The authors hereby grant permission to use, copy, modify, distribute, #
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# and license this software and its documentation for any purpose, provided #
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# that existing copyright notices are retained in all copies and that this #
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# notice is included verbatim in any distributions. No written agreement, #
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# license, or royalty fee is required for any of the authorized uses. #
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# Modifications to this software may be copyrighted by their authors #
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# and need not follow the licensing terms described here, provided that #
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# the new terms are clearly indicated on the first page of each file where #
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# they apply. #
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# #
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# This is the start routine of your CR16 program. #
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# It is linked with your application automatically. You can use #
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# this routine as a template and modify it to your needs, yet this #
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# file must be supplied for the compiler. #
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# It is assumed that the following symbols are defined in your linker #
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# script: __STACK_START, __ISTACK_START #
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##############################################################################
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.text
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#ifdef __CR16CP__
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.align 4
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#else
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.align 2
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#endif
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.global _main
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.global _atexit
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.global _exit
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.global _start
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.global __fini
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.global __init
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.global __STACK_START
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.global __ISTACK_START
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_start:
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#----------------------------------------------------------------------------#
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# Initialize the stack pointers. The constants __STACK_START and #
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# __ISTACK_START should be defined in the linker script. #
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movd $__STACK_START, (sp)
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movd $__ISTACK_START, (r1,r0)
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lprd (r1,r0), isp
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#----------------------------------------------------------------------------#
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# Initialize the default sections according to the linker script. #
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# bal (ra), __init_bss_data
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#----------------------------------------------------------------------#
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# Set the Extended Dispatch bit in the CFG register. This is the #
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# default configuration for CR16C. #
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spr cfg, r0 # Set dispatch table width
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orw $0x100, r0
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lpr r0, cfg
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#----------------------------------------------------------------------------#
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#----------------------------------------------------------------------------#
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# Handle global and static constructurs execution and setup #
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# destructors to be called from exit. #
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bal (ra),__init
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movd $__fini@c, (r3,r2)
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bal (ra), _atexit
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#----------------------------------------------------------------------------#
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# Jump to the main function in your application. #
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#ifdef __INT32__
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movd $0, (r3,r2) # Number of arguments
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movd $0, (r5,r4) # conatins pointer to argument string.
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#else
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movw $0, r2 # Number of arguments
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movd $0, (r4,r3) # conatins pointer to argument string.
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#endif
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bal (ra), _main
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#----------------------------------------------------------------------------#
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# Upon returning from the main function (if it isn't an infinite loop), #
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# jump to the exit function. The exit function is located in the #
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# library 'libc.a'. #
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#ifdef __INT32__
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movd (r1,r0), (r3,r2) # _main return value gets forwarded.
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#else
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movw r0, r2 # _main return value gets forwarded.
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#endif
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br _exit # returns control to the functional simulator.
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