uxn/projects/examples/exercises/brainfuck.tal

( usage: cat program.bf | uxncli brainfuck.rom )

|10 @Console &vector $2 &read $1 &pad $4 &type $1 &write $1 &error $1

|0100

@on-reset ( -> )
	;on-console .Console/vector DEO2
	BRK

@on-console ( -> )
	.Console/read DEI DUP #20 GTH ?{
		POP <eval>
		#0000 .Console/vector DEO2
		#010f DEO
		BRK }
	[ LIT2 &ptr =program ] INC2k ,&ptr STR2
	STA
	BRK

@<eval> ( -- )
	[ LIT2r =on-console/ptr ] LDA2r ;program
	&while ( -- )
		LDAk [ LIT "+ ] NEQ ?{ LDAkr STHr INC STH2kr STA }
		LDAk [ LIT "- ] NEQ ?{ LDAkr STHr #01 SUB STH2kr STA }
		LDAk [ LIT "> ] NEQ ?{ INC2r }
		LDAk [ LIT "< ] NEQ ?{ [ LIT2r 0001 ] SUB2r }
		LDAk [ LIT ". ] NEQ ?{ LDAkr [ LITr 18 ] DEOr }
		LDAk [ LIT "[ ] NEQ ?{ goto-next }
		LDAk [ LIT "] ] NEQ ?{ goto-back }
		INC2 LDAk ?&while
	POP2 POP2r JMP2r

@goto-next ( `mem* prg* -- )
	OVR2r LDAr STHr ?{ JMP2r }
	[ LITr 00 ] INC2
	&loop ( -- )
		LDAk [ LIT "[ ] NEQ ?{ INCr }
		LDAk [ LIT "] ] NEQ ?{
			STHkr ?{ POPr JMP2r }
			[ LITr 01 ] SUBr }
		INC2 !&loop

@goto-back ( `mem* prg* -- )
	OVR2r LDAr STHr ?{ JMP2r }
	[ LITr 00 ] #0001 SUB2
	&loop ( -- )
		LDAk [ LIT "] ] NEQ ?{ INCr }
		LDAk [ LIT "[ ] NEQ ?{
			STHkr ?{ POPr JMP2r }
			[ LITr 01 ] SUBr }
		#0001 SUB2 !&loop

@program