ASSEMBLER - STATUSBITS - PROCESSOR FLAGS 
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TOOL: 		Built-In ML-Monitor / RONMON-Special, RUN-11-1987-GERMAN {Commodore C128}
Language: 	Assembler 
Extra:		-
Author: 	Misel Zivanovic
Note:		(C) 18th DEC 2025 - www.lived.ch, mzretro.ch
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Commodore C128 has no command to show you the FLAG status, however I've found in RUN-COMPUTER-MAGAZINE
a listing which is giving us RONMON and there you have a command: B {and ENTER} which is showing
the status of the FLAGS.

To know what to do with that in first place, i made this listing below.
It should help you to feel yourself like at home while programming in assembler! {I guess, haha}

If nothing else, now you know how:
	
	- the numbers between 0 and 127 are POSITIVE 
	- the numbers between 128 and 255 are NEGATIVE!

And you immediately learned BLP and BMI branch commands

	- BPL - Branch if the result is PLUS  {Positive}
	- BMI - Branch if the result is MINUS {NEGATIVE}
			
|---------------------------------------|------------------------|--------------------------------------|	
|CPU-STATUS BITS {0 - 7}		|FLAGS			 | WHO'S KNOCKING ON THE DOOR!?		|
|---------------------------------------|------------------------|--------------------------------------|
|     					|			 | 					|	
|Bit -| 7 | 6 | 5 | 4 | 3 | 2 | 1| 0 |	|7 - NEGATIVE *	 	 | {Branch BPL	  }   {Branch: BMI    } |
|Flag-| N | V | - | B | D | I | Z| C |	|6 - OVERFLOW		 | {Branch: BVC, BVS  		      } |
|---------------------------------------|5 - *** UNUSED ***	 | -					|
|					|4 - BREAK Command	 | {BRK command   		      } |
|					|3 - DECIMAL Mode	 | {SED SEt Decimal or Clear = CLD    } |
|					|2 - INTERRUPT DISABLED  | {SEI SEt Interrupt or Clear = CLI  } |
|					|1 - ZERO		 | {BNE and BEQ commands are using it } |
|					|0 - CARRY		 | {BCC and BCS commands are using it } | 
|---------------------------------------|------------------------|--------------------------------------|
					|* =								|
					|{#$00-#$7f = POSITIVE VALUES} & {#$80 - #$ff = NEGATIVE VALUES}|
					|								|	
					|---------------------------------------------------------------|


STATUS BITS {FLAGS| ARE EFFECTED BY THE FOLLOWING COMMANDS:

|----------------------------------|
|NEGATIV  		     BIT 7 |
|				   |
|----------------------------------|
|ADC, AND, ASL, BIT, CMP, CPY, CPX |
|DEC, DEX, DEY, EOR, INC, INX, INY |
|LDA, LDX, LDY, LSR, ORA, PLA, PLP |
|ROL, ROR, RTI, SBC, TAX, TAY, TSX |
|TXA, TXS, TYA			   |	
|----------------------------------|



|----------------------------------|
|OVERFLOW  		     BIT 6 |
|				   |
|----------------------------------|
|ADC, BIT, CLV, PLP, RTI, SBC	   |
|----------------------------------|



|----------------------------------|
|UNUSED  		     BIT 5 |
|				   |
|----------------------------------|



|----------------------------------|
|BREAK   		     BIT 4 |
|				   |
|----------------------------------|
|BRK				   |
|----------------------------------|



|----------------------------------|
|DECIMAL  		     BIT 3 |
|				   |
|----------------------------------|
|CLD, PLP, RTI, SED		   |
|----------------------------------|



|----------------------------------|
|INTERRUPT  		     BIT 2 |
|				   |
|----------------------------------|
|BRK, CLI, PLP, RTI, SEI	   |
|----------------------------------|



|----------------------------------|
|ZERO     		     BIT 1 |
| 				   |
|----------------------------------|
|ADC, AND, ASL, BIT, CMP, CPY, CPX |
|DEC, DEX, DEY, EOR, INC, INX, INY |
|LDA, LDX, LDY, LDY, LSR, ORA, PLA |
|PLP, ROL, RTI, SBC, TAX, TAY, TSX |
|TXA, TXS, TYA			   |	
|----------------------------------|



|----------------------------------|
|CARRY			     BIT 0 |
|				   |
|----------------------------------|
|ADC, ASL, CMP, CLC, CPX, CPY, LSR |
|PLP, ROL, ROR, RTI, SBC, SEC	   |
|----------------------------------|