( advent of code 2025, day 2, first star )

%dbg { #010e DEO }


|00
@Buffers/num $f &endnum $1
@Buffers/end $f &endend $1

$1 @Buffers/read $f &endread $1

@Buffers/sum $1f &endsum $1


|100
@on-reset ( -> )
	banner
	first-star
	BRK

@banner ( -- )
	;/str !puts
@banner/str
	"advent 20 "of 20 "code 20 "2025, 20 "day 20 "2, 20 "first 20 "star 0a 00


( first star )

@astr $1 "89 &end "5 $1
@bstr $1 "10 &end "9 $1

@first-star ( -- )
	;astr/end ;bstr/end sumstrs
	
	;astr puts endl

	( Input/read )
	JMP2r

@first-star/on-input ( b -- )
	JMP2r


( stdlib )

@endl ( n -- )
	#0a18 DEO JMP2r

@puts ( str* -- )
	LDAk #18 DEO
	INC2 LDAk ?puts

	POP2 JMP2r

@putdec2 ( n* -- )
	[ LITr 00 ]

	&loop
		#000a DIV2k STH2k
		MUL2 SUB2
		[ LIT "0 ] ADD NIP
		STH2r ROT STH
		ORAk ?/loop
	POP2
	
	&loop2
		STHr #18 DEO
		STHrk ?/loop2
	POPr JMP2r

@incs ( n* -- )
	LDAk ?{
		[ LIT "1 ]
		ROT ROT STA
		JMP2r
	}
	
	LDAk
	[ LIT "9 ] NEQ ?{
		DUP2
		[ LIT "0 ]
		ROT ROT STA
		&subone
		#0001 SUB2 !incs
	}
	LDAk INC
	ROT ROT STA
	JMP2r

@findend ( p* -- p* )
	INC2 LDAk ?findend
	JMP2r

@sumstrs ( a* b* -- )			( takes pointers to the last digits of each number )
	LDAk STH SWP2 LDAk STHr		( b* a* ac bc ) dbg
	DUP ?{ POP2 POP2 POP2 JMP2r }	( we've reached the end of b )
	OVR ?{ NIP [ LIT "0 ] }		( if we're at the end of a, pad with 0s )
	[ LIT2 "00 ] SUB2 ADD		( b* a* a+b )
	DUP #0a LTH ?{			( overflow )
		#0a SUB STH
		DUP2 incs/subone	( carry )
		STHr
	}
	[ LIT "0 ] ADD			( convert back to ascii )
	ROTk ROT STA POP		( save digit )
	#0001 SUB2
	SWP2 #0001 SUB2
	!sumstrs			( loop! )


( object lib )

@Input/filename "02.input.test 00
@Input/read ( -- )
	#01ab DEO
	;/filename #a8 DEO2
	
	&loop
		;/byte #ac DEO2
		#a3 DEI #00 EQU ?/endloop	( EOF )
		[ LIT &byte $1 ]
		first-star/on-input
		!/loop

	&endloop
	POP2 JMP2r

	
@Number/one-byte ( b -- )
	#00 SWP
	LIT "0 SUB
	[ LIT2 &val 0000 ]
	#000a MUL2 ADD2
	,/val STR2
	JMP2r
@Number/get ( -- n* )
	,/val LDR2 JMP2r
@Number/reset ( -- )
	#0000 ,/val STR2 JMP2r


( problem code )