mirror of
https://gitlab.com/freepascal.org/fpc/source.git
synced 2025-04-22 01:09:27 +02:00
144 lines
3.7 KiB
ObjectPascal
144 lines
3.7 KiB
ObjectPascal
{******************************************************************************
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Startup code for an avr simulator
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******************************************************************************}
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unit avrsim;
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interface
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var
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OUTPUTREG : byte absolute $20;
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EXITCODEREG : byte absolute $21;
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HALTREQUEST : byte absolute $22;
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EXCEPTIONJMPZERO : boolean absolute 52;
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implementation
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uses
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consoleio,heapmgr;
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procedure PASCALMAIN; external name 'PASCALMAIN';
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procedure _FPC_haltproc; public name '_haltproc'; noreturn;
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begin
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EXITCODEREG:=exitcode;
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HALTREQUEST:=1;
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{ really stop }
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while true do
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;
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end;
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var
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_data: record end; external name '__data_start';
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_edata: record end; external name '__data_end';
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_etext: record end; external name '_etext';
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_bss_start: record end; external name '__bss_start';
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_bss_end: record end; external name '__bss_end';
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_stack_top: record end; external name '_stack_top';
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__dtors_end: record end; external name '__dtors_end';
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procedure _FPC_start; assembler; nostackframe; noreturn; public name '_START'; section '.init';
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asm
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jmp __dtors_end // Jump to last linker symbol before .init0
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// Interrupt vectors to be added here
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end;
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procedure _FPC_init_zeroreg_SP; assembler; nostackframe; noreturn; public name '_init_zeroreg_SP'; section '.init2';
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asm
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{$ifdef CPUAVR_16_REGS}
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clr r17
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{$else CPUAVR_16_REGS}
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clr r1
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{$endif CPUAVR_16_REGS}
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{$ifndef CPUAVR1}
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// load stack pointer
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ldi r30,lo8(_stack_top)
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out 0x3d,r30
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ldi r30,hi8(_stack_top)
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out 0x3e,r30
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{$endif CPUAVR1}
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end;
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procedure _FPC_copy_data; assembler; nostackframe; noreturn; section '.init4';
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asm
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// Initialize .data section
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ldi XL,lo8(_data)
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ldi XH,hi8(_data)
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ldi YH,hi8(_edata)
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ldi ZL,lo8(_etext)
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{$ifdef CPUAVR_16_REGS}
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ldi ZH,hi8(_etext)+(0x40) // program memory mapped to $4000 in data space
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{$else CPUAVR_16_REGS}
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ldi ZH,hi8(_etext)
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{$endif CPUAVR_16_REGS}
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rjmp .LCopyDataLoopEntry
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.LCopyDataLoop:
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{$ifdef CPUAVR_16_REGS}
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ld r16, Z+
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{$else CPUAVR_16_REGS}
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lpm r16, Z+
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{$endif CPUAVR_16_REGS}
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st X+, r16
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.LCopyDataLoopEntry:
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cpi XL, lo8(_edata)
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cpc XH, YH
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brne .LCopyDataLoop
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// Zero .bss section
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ldi XL,lo8(_bss_start)
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ldi XH,hi8(_bss_start)
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ldi YH,hi8(_bss_end)
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{$ifdef RELBRANCHES}
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rjmp .LZeroBssLoopEntry
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{$else RELBRANCHES}
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jmp .LZeroBssLoopEntry
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{$endif RELBRANCHES}
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.LZeroBssLoop:
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{$ifdef CPUAVR_16_REGS}
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st X+, r17
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{$else CPUAVR_16_REGS}
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st X+, r1
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{$endif CPUAVR_16_REGS}
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.LZeroBssLoopEntry:
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cpi XL, lo8(_bss_end)
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cpc XH, YH
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brne .LZeroBssLoop
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end;
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procedure _FPC_jmp_main; noreturn; assembler; nostackframe; section '.init9';
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asm
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{$ifdef RELBRANCHES}
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rjmp PASCALMAIN
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{$else RELBRANCHES}
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jmp PASCALMAIN
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{$endif RELBRANCHES}
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end;
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function WriteChar(ACh: AnsiChar; AUserData: pointer): boolean;
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begin
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WriteChar:=true;
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OUTPUTREG:=ord(ACh);
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end;
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function ReadChar(var ACh: AnsiChar; AUserData: pointer): boolean;
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begin
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ReadChar:=true;
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ACh:=#0;
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end;
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begin
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EXCEPTIONJMPZERO:=true;
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OpenIO(Input, @WriteChar, @ReadChar, fmInput, nil);
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OpenIO(Output, @WriteChar, @ReadChar, fmOutput, nil);
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OpenIO(ErrOutput, @WriteChar, @ReadChar, fmOutput, nil);
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OpenIO(StdOut, @WriteChar, @ReadChar, fmOutput, nil);
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OpenIO(StdErr, @WriteChar, @ReadChar, fmOutput, nil);
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end.
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