328 lines
9.3 KiB
NASM
328 lines
9.3 KiB
NASM
;-----------------------------------------------------------------------
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;
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; This file contains the M16C C startup routine and must usually
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; be tailored to suit customer's hardware.
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;
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; Copyright 2002 IAR Systems. All rights reserved.
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;
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; $Revision: 1.16 $
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;
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;-----------------------------------------------------------------------
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MODULE ?cstart
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PUBLIC __program_start
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PUBLIC __data16_init
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PUBLIC __data16_zero
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PUBLIC ?cstart_call_ctors
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EXTERN main
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EXTERN exit
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EXTERN __call_ctors
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EXTERN __low_level_init
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EXTERN ?GENERIC_MOVE_LONG_L08
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EXTERN RelocatableVectTbl
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;------------------------------------------------------
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; Useful macros
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;------------------------------------------------------
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; Load 24-bit constant value to (high,low)
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LD24 MACRO value,high,low
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MOV.B #BYTE3(value),high
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MOV.W #LWRD(value),low
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ENDM
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; Load 32-bit constant value to (high,low)
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LD32 MACRO value,high,low
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MOV.W #HWRD(value),high
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MOV.W #LWRD(value),low
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ENDM
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; Load a stack-pointer with last even address of segment
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LDSTACK MACRO segment,reg
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LDC #sfe(segment), reg
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ENDM
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;------------------------------------------------------
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; __program_start - Reset vector should point to here.
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;
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; Calls __low_level_init to perform initialization
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; before initializing segments and calling main.
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; If the function returns 0 no segment initialization
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; should take place.
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;
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; Link with your own version of __low_level_init to
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; override the default action: do nothing but return 1.
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;------------------------------------------------------
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RSEG CSTACK
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RSEG ISTACK
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RSEG CSTART:CODE:NOROOT
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REQUIRE call_main
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__program_start:
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LDC #sfe(ISTACK), ISP ; Set up interrupt stack
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FCLR U ; Select interrupt stack
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LDC #sfe(CSTACK), SP ; Set up C stack
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LDINTB #RelocatableVectTbl ; Set up INTB register
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JSR.A __low_level_init ; Call __low_level_init
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;-----------------------------------------------------------
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; Run-time test whether we should do segment initialization
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;-----------------------------------------------------------
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TST.B R0L, R0L
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JNE do_segment_init
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JMP skip_segment_init
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do_segment_init:
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;------------------------------------------------------
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; Perform segment initialization of DATA16 memory.
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;------------------------------------------------------
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RSEG DATA16_Z
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RSEG CSTART:CODE:NOROOT
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__data16_zero:
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MOV.W #sizeof(DATA16_Z), R3
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MOV.W #sfb(DATA16_Z), A1
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MOV.B #0, R0L
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SSTR.B
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RSEG DATA16_I
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RSEG DATA16_ID
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RSEG CSTART:CODE:NOROOT
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__data16_init:
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MOV.W #sizeof(DATA16_ID), R3
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MOV.W #sfb(DATA16_I), A1
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LD24 sfb(DATA16_ID), R1H, A0
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SMOVF.B
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RSEG CSTART:CODE:NOROOT
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skip_segment_init:
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; Fall through to next required CSTART segment part
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;------------------------------------------------------
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; Call constructors
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;------------------------------------------------------
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RSEG DIFUNCT
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RSEG CSTART:CODE:NOROOT
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PUBLIC ?cstart_call_ctors
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EXTERN __call_ctors
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?cstart_call_ctors:
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PUSH.W #HWRD(sfe(DIFUNCT))
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PUSH.W #LWRD(sfe(DIFUNCT))
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LD32 sfb(DIFUNCT),R2,R0
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JSR.A __call_ctors
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; Fall through to next required CSTART segment part
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;------------------------------------------------------
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; Call main and exit
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;------------------------------------------------------
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; This segment part is marked as ROOT, since it must
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; be preserved by the linker.
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;
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RSEG CSTART:CODE:NOROOT
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call_main:
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MOV.W #0, R0 ; Call main with argc = 0
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JSR.A main
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JMP.A exit ; Argument to exit is return value of main
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;------------------------------------------------------
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; Fixed interrupt table.
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;
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; We install all fixed interrupts in a segment called
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; INTVEC1. All fixed interrupts have a hard coded name.
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; Write an interrupt handler in C using this name, with
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; no vector specification, and it will replace the
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; default handler.
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;------------------------------------------------------
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EXTERN __undefined_instruction_handler
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EXTERN __overflow_handler
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EXTERN __break_instruction_handler
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EXTERN __address_match_handler
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EXTERN __single_step_handler
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EXTERN __watchdog_timer_handler
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EXTERN __DBC_handler
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EXTERN __NMI_handler
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; Labels for the ID Code Check Function.
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; (To be initialized in the linker file)
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EXTERN _ID_CODE_1
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EXTERN _ID_CODE_2
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EXTERN _ID_CODE_3
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EXTERN _ID_CODE_4
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EXTERN _ID_CODE_5
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EXTERN _ID_CODE_6
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EXTERN _ID_CODE_7
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EXTERN _OFS_VALUE
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PUBLIC ??intvec_start
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COMMON INTVEC1:NOROOT
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??intvec_start:
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DC24 __undefined_instruction_handler
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DC8 _ID_CODE_1
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DC24 __overflow_handler
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DC8 _ID_CODE_2
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DC24 __break_instruction_handler
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DC8 0
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DC24 __address_match_handler
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DC8 _ID_CODE_3
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DC24 __single_step_handler
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DC8 _ID_CODE_4
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DC24 __watchdog_timer_handler
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DC8 _ID_CODE_5
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DC24 __DBC_handler
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DC8 _ID_CODE_6
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DC24 __NMI_handler
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DC8 _ID_CODE_7
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DC24 __program_start ; Reset vector
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DC8 _OFS_VALUE
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ENDMOD
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;------------------------------------------------------
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; Default handlers for fixed interrupts
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;------------------------------------------------------
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MODULE __undefined_instruction
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EXTERN ??reit
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REQUIRE ??reit
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PUBLIC __undefined_instruction_handler
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RSEG CSTART:CODE:NOROOT(1)
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__undefined_instruction_handler:
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; Fall through to ??reit
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ENDMOD
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MODULE __overflow
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EXTERN ??reit
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REQUIRE ??reit
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PUBLIC __overflow_handler
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RSEG CSTART:CODE:NOROOT(1)
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__overflow_handler:
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; Fall through to ??reit
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ENDMOD
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MODULE __break_instruction
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EXTERN ??reit
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REQUIRE ??reit
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PUBLIC __break_instruction_handler
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RSEG CSTART:CODE:NOROOT(1)
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__break_instruction_handler:
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; Fall through to ??reit
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ENDMOD
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MODULE __address_match
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EXTERN ??reit
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REQUIRE ??reit
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PUBLIC __address_match_handler
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RSEG CSTART:CODE:NOROOT(1)
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__address_match_handler:
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; Fall through to ??reit
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ENDMOD
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MODULE __single_step
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EXTERN ??reit
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REQUIRE ??reit
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PUBLIC __single_step_handler
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RSEG CSTART:CODE:NOROOT(1)
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__single_step_handler:
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; Fall through to ??reit
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ENDMOD
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MODULE __watchdog_timer
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EXTERN ??reit
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REQUIRE ??reit
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PUBLIC __watchdog_timer_handler
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RSEG CSTART:CODE:NOROOT(1)
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__watchdog_timer_handler:
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; Fall through to ??reit
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ENDMOD
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MODULE __DBC
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EXTERN ??reit
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REQUIRE ??reit
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PUBLIC __DBC_handler
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RSEG CSTART:CODE:NOROOT(1)
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__DBC_handler:
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; Fall through to ??reit
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ENDMOD
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MODULE __NMI
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EXTERN ??reit
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REQUIRE ??reit
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PUBLIC __NMI_handler
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RSEG CSTART:CODE:NOROOT(1)
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__NMI_handler:
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; Fall through to ??reit
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ENDMOD
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;------------------------------------------------------
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; Return from interrupt
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;------------------------------------------------------
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MODULE __reit
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PUBLIC ??reit
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RSEG CSTART:CODE:NOROOT(1)
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EXTERN ??intvec_start
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REQUIRE ??intvec_start
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??reit:
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REIT
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ENDMOD
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;------------------------------------------------------
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; FUNCTION: __low_level_init
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;
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; You can replace this routine by linking with your
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; own version.
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;
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; The default action is to do nothing and return 1.
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;------------------------------------------------------
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MODULE __low_level_init
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PUBLIC __low_level_init
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RSEG CSTART:CODE:NOROOT
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__low_level_init:
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MOV.B #1,R0L
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RTS
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ENDMOD
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;------------------------------------------------------
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; __overflow - This variable is used by the intrinsic
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; functions __RMPA_W_overflow and
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; __RMPA_B_overflow.
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;------------------------------------------------------
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MODULE __overflow
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PUBLIC __overflow
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EXTERN __data13_zero
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RSEG DATA13_Z:NEAR:NOROOT
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__overflow:
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DC8 0
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REQUIRE __data13_zero
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END
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