uxn/projects/software/assembler.usm

;tree { search-key 2 max-key-len 1 }
;assembler { pass 1 state 1 token 2 scope-len 1 scope 80 heap 2 addr 2 subtree 2 vartmp 2 field 2 }

%HCF { #0000 DIV }
%SHORT_FLAG { #20 }
%RETURN_FLAG { #40 }

( devices )

|0100 ;System { vector 2 pad 6 r 2 g 2 b 2 }
|0110 ;Console { vector 2 pad 6 char 1 byte 1 short 2 string 2 }
|0120 ;Screen { vector 2 width 2 height 2 pad 2 x 2 y 2 addr 2 color 1 }
|0130 ;Audio { wave 2 envelope 2 pad 4 volume 1 pitch 1 play 1 value 2 delay 2 finish 1 }
|0140 ;Controller { vector 2 button 1 key 1 }
|0160 ;Mouse { vector 2 x 2 y 2 state 1 chord 1 }
|0170 ;File { vector 2 pad 6 name 2 length 2 load 2 save 2 }
|01a0 ;DateTime { year 2 month 1 day 1 hour 1 minute 1 second 1 dotw 1 doty 2 isdst 1 refresh 1 }

( vectors )

|0200 ^RESET JMP

@RESET
	,assembler-heap-start =assembler.heap
	#0070 =assembler.addr

	,$read-filename =File.name
	#1000 =File.length
	#f000 =File.load

	#f000 #1000 ^assemble-chunk JSR
	HCF

	$read-filename [ etc/assembler-test.usm 00 ]

@assemble-chunk ( ptr* len* -- 00 if EOF found in chunk
                            OR assembled-up-to-ptr* 01 if reached end of chunk )
	OVR2 ADD2 STH2
	#0001 SUB2

	$per-token
	DUP2 STH2

	$loop
	#0001 ADD2
	DUP2 PEK2
	#20 GTH ^$loop JNZ

	DUP2 OVR2r STH2r LTS2 ^$valid JNZ
	SWP2r POP2r POP2
	STH2r #0001 ADD2
	#01 JMP2r

	$valid
	DUP2 PEK2 #00 OVR2 POK2
	STH2r #0001 ADD2 ^assemble-token JSR
	^$per-token JNZ

	POP2 POP2r #00 JMP2r

@assemble-macro ( macro-ptr* -- )
	DUP2 ,strlen JSR2 DUP2 #0000 EQU2 ^$end JNZ
	OVR2 ^assemble-token JSR
	ADD2 #0001 ADD2
	^assemble-macro JMP

	$end
	POP2 POP2
	JMP2r

@assemble-token ( string-ptr* -- )
	( get location of tree )
	DUP2
	,state-machine-pointers #00 ~assembler.state ,highest-bit JSR2 #0004 MUL2 ADD2
	DUP2 STH2
	( see if first char is recognised )
	SWP2 #01 ,traverse-tree JSR2
	^$not-found JNZ
	( skip first character of token )
	SWP2 #0001 ADD2 =assembler.token
	( tail call handling function defined in tree )
	POP2r JMP2

	$not-found
	( not interested in incoming-ptr )
	POP2
	=assembler.token
	( tail call default handling function defined in state-machine-pointers )
	LIT2r [ 0002 ] ADD2r LDR2r
	JMP2r

@parse-hex-length ( string-ptr* -- value 01 if one or two hex digits
                                OR 00 otherwise )
	DUP2 #0001 ADD2 PEK2 ^parse-hex-string-try-two JNZ
	PEK2 ^parse-hex-digit JSR DUP #04 SFT ^parse-hex-string-fail1 JNZ
	#01 JMP2r

@parse-hex-string ( string-ptr* -- value* 02 if four hex digits
                                OR value 01 if two hex digits
                                OR 00 otherwise )
	DUP2 #0004 ADD2 PEK2 #00 EQU ^$try-four JNZ
	$try-two
	DUP2 #0002 ADD2 PEK2 ^$fail2 JNZ
	$known-two
	DUP2 PEK2 ^parse-hex-digit JSR DUP #04 SFT ^$fail3 JNZ ROT ROT
	#0001 ADD2 PEK2 ^parse-hex-digit JSR DUP #04 SFT ^$fail2 JNZ
	SWP #40 SFT ORA #01 JMP2r

	$fail3 POP
	$fail2 POP
	$fail1 POP #00 JMP2r

	$try-four
	DUP2 #0002 ADD2 ^$known-two JSR ^$maybe-four JNZ
	^$try-two JMP

	$maybe-four
	ROT ROT ^$known-two JSR ^$four JNZ
	^$fail1 JMP

	$four
	SWP #02 JMP2r

@parse-hex-digit ( charcode -- 00-0f if valid hex
                            -- 10-ff otherwise )
	DUP #3a LTH ^$digit JNZ
	DUP #60 GTH ^$lowercase JNZ
	DUP #40 GTH ^$uppercase JNZ
	JMP2r

	$digit ( #30 is #00 )
	#30 SUB JMP2r

	$lowercase ( #61 is #0a )
	#57 SUB JMP2r

	$uppercase ( #41 is #0a )
	#37 SUB JMP2r

@find-opcode ( name* -- byte 00 if valid opcode name
                     OR 01 if not found )
	,opcodes-tree SWP2 #03 ^traverse-tree JSR
	^$nomatch JNZ
	,opcodes-asm SUB2 #0007 DIV2
	SWP JMP2r

	$nomatch
	DUP2 EQU2 JMP2r

@traverse-tree ( tree-ptr* search-key* max-key-len --
		binary-ptr* 00 if key matched
		OR incoming-ptr* 01 if key not found )
	=tree.max-key-len =tree.search-key

	$loop
	DUP2 LDR2 #0000 NEQ2 ^$valid-node JNZ
	#01 JMP2r

	$valid-node
	LDR2 DUP2 STH2 #0004 ADD2 ^strcmp-tree JSR
	DUP ^$nomatch JNZ
	POP2r JMP2r

	$nomatch
	#07 SFT #02 MUL #00 SWP
	STH2r ADD2
	^$loop JMP

@strcmp-tree ( node-key* -- order if strings differ
                         OR after-node-key* 00 if strings match )
	~tree.search-key STH2
	~tree.max-key-len

	$loop ( node-key* key-len in wst, search-key* in rst )
	DUP ^$keep-going JNZ

	( exhausted key-len, match found )
	POP2r
	JMP2r

	$keep-going
	#01 OVR2 PEK2 DUP2r PEK2r STHr
	DUP2 ORA ^$not-end JNZ

	( end of C strings, match found )
	POP2r POP ROT POP SWP ADD2 #00
	JMP2r

	$not-end
	SUB DUP ^$nomatch JNZ
	POP SUB
	LIT2r [ 0001 ] ADD2r STH
	LIT2  [ 0001 ] ADD2  STHr
	^$loop JMP

	$nomatch
	STH POP2 POP2 STHr POP2r
	JMP2r

@highest-bit ( n -- 00 if n is 00
                 OR 01 if n is 01
                 OR 02 if n is 02..03
                 OR 03 if n is 04..07
                 OR 04 if n is 08..0f
                 ..
                 OR 08 if n is 80..ff )
	DUP #00 NEQ JMP JMP2r
	DUP #01 SFT ORA
	DUP #02 SFT ORA
	DUP #04 SFT ORA
	#1d MUL #05 SFT #00 SWP ,$lookup ADD2 PEK2
	JMP2r

	$lookup
	[ 01 06 02 07 05 04 03 08 ]

@memcpy ( src-ptr* dest-ptr* length* -- after-dest-ptr* )
	SWP2 STH2

	$loop
	DUP2 ORA ^$keep-going JNZ
	POP2 POP2 STH2r
	JMP2r

	$keep-going
	#0001 SUB2
	SWP2 DUP2 PEK2 DUP2r STH2r POK2
	#0001 ADD2 SWP2
	LIT2r [ 0001 ] ADD2r
	^$loop JMP

@strcpy ( src-ptr* dest-ptr* -- after-dest-ptr* )
	OVR2 ^strlen JSR #0001 ADD2 ^memcpy JMP

@strlen ( string-ptr* -- length* )
	DUP2 #0001 SUB2
	$loop
	#0001 ADD2
	DUP2 PEK2 ^$loop JNZ
	SWP2 SUB2
	JMP2r

@append-heap ( string-ptr* -- after-string-ptr* )
	~assembler.heap ,strcpy JSR2
	DUP2 =assembler.heap
	JMP2r

@append-tree ( string-ptr* incoming-ptr* -- binary-data* )
	~assembler.heap SWP2 STR2
	,$zero-pointers ~assembler.heap #0004 ^memcpy JSR =assembler.heap
	^append-heap JSR
	JMP2r

	$zero-pointers [ 0000 0000 ]

@add-label ( label-flags string-ptr* tree-ptr* -- )
	OVR2 #ff ,traverse-tree JSR2
	^$new-label JNZ

	( label already exists, check the flags and addr value )
	SWP2 POP2
	DUP2 #0001 ADD2 LDR2 ~assembler.addr EQU2 ^$addr-okay JNZ
	( FIXME address is different to previous run, or label defined twice )
	$addr-okay
	PEK2 EQU ^$type-okay JNZ
	( FIXME node type is different to before )
	$type-okay
	JMP2r

	$new-label
	^append-tree JSR
	(
	~assembler.heap SWP2 STR2
	,$zero-pointers ~assembler.heap #0004 ^memcpy JSR =assembler.heap
	~assembler.heap ,strcpy JSR2
	)
	DUP2 STH2 POK2 STH2r
	DUP2 #0001 ADD2 ~assembler.addr SWP2 STR2
	#0003 ADD2 =assembler.heap
	JMP2r

@lookup-label ( string-ptr* -- address* node-type if found
                            OR false-address* 00 if not found )
	DUP2
	$loop
	DUP2 #0001 ADD2 SWP2 PEK2
	DUP #2e EQU ^$dotted JNZ
	^$loop JNZ
	DUP2 EOR2 ( faster than POP2 #0000 )
	=assembler.field

	$main
	DUP2 ,label-tree SWP2 #ff ,traverse-tree JSR2
	^$not-found JNZ

	SWP2 POP2
	~assembler.field #0000 EQU2 ^$end JNZ
	DUP2 PEK2 #80 LTH ^$not-found JNZ
	#0003 ADD2 ~assembler.field #ff ,traverse-tree JSR2
	^$not-found JNZ

	$end
	DUP2 #0001 ADD2 LDR2 SWP2 PEK2
	JMP2r

	$not-found
	POP2
	( FIXME complain about missing label )
	POP2
	( false-address is out of reach for JMP )
	~assembler.addr #8765 ADD2
	#00
	JMP2r

	$dotted
	DUP OVR2 =assembler.field
	EOR ROT ROT #0001 SUB2 POK2
	^$main JMP

@write-byte ( byte -- )
	( FIXME ) =Console.byte
	~assembler.addr #0001 ADD2 =assembler.addr
	JMP2r

@write-short ( short -- )
	( FIXME ) =Console.short
	~assembler.addr #0002 ADD2 =assembler.addr
	JMP2r

@label-tree .l-root
@macro-tree [ 0000 ]

@opcodes
	(
		The code for this section is automatically generated, and needs to be
		regenerated when the opcode list in src/assembler.c is updated.

		After editing src/assembler.c, run "lua etc/assembler-trees.lua"
		and this file will be edited automatically.

		This is the first example of a binary tree in this code, so let's
		explore them in general. The format of a tree node in memory is:

		left-node* right-node* node-key-cstring binary-data

		and the general algorithm is to compare the key you're looking for
		against node-key-cstring, and move to the node pointed to by left-node*
		or right-node* if the keys don't match. If your key sorts earlier than
		use left-node*, otherwise go to right-node*. When you find a node that
		matches your key, traverse-bintree gives you a pointer to the
		binary-data straight after the node-key-cstring. This data can contain
		anything you want: fixed length fields, executable code... in this case
		of this opcode tree, we store nothing. traverse-bintree is passed the
		maximum length of node-key-cstring, not including the zero, so the zero
		can be omitted if the string is at that maximum length.

		If the key isn't present in the tree, you'll eventually get to a node
		where the left-node* or right-node* pointer you'll need to follow is
		null (0000). traverse-bintree will give you the location of that
		pointer, so if you want to insert another node, you can write it to the
		heap and overwrite the pointer with the new node's location. This
		approach works even if the tree is completely empty and the pointer
		you've provided to the root node is null, since that pointer gets
		updated to point to the first node without needing any special logic.

		The ordering of nodes in memory is totally arbitrary, so for pre-
		prepared trees like this one we can have our own meaning for the order
		of the nodes. By ordering the opcodes by their byte value, we can find
		the byte by subtracting $asm from the binary-data pointer and dividing
		by seven (the size of each node). By multiplying the byte value by seven
		and adding to $disasm, we get the opcode name when disassembling too.
	)
	$tree   .$op-lth ( opcode tree )
	$start
	$op-brk .$op-add .$op-dup $disasm [ BRK ] $asm
	$op-nop .$op-mul .$op-ovr         [ NOP ]
	$op-lit [ 0000 ] [ 0000 ]         [ LIT ]
	$op-pop [ 0000 ] [ 0000 ]         [ POP ]
	$op-dup .$op-div .$op-eor         [ DUP ]
	$op-swp [ 0000 ] [ 0000 ]         [ SWP ]
	$op-ovr .$op-ora .$op-pek         [ OVR ]
	$op-rot .$op-pop .$op-sft         [ ROT ]
	$op-equ .$op-brk .$op-jnz         [ EQU ]
	$op-neq [ 0000 ] [ 0000 ]         [ NEQ ]
	$op-gth [ 0000 ] [ 0000 ]         [ GTH ]
	$op-lth .$op-equ .$op-pok         [ LTH ]
	$op-gts .$op-gth .$op-jmp         [ GTS ]
	$op-lts [ 0000 ] [ 0000 ]         [ LTS ]
	        [ 0000 ] [ 0000 ]         [ ??? ]
	        [ 0000 ] [ 0000 ]         [ ??? ]
	$op-pek [ 0000 ] [ 0000 ]         [ PEK ]
	$op-pok .$op-nop .$op-sth         [ POK ]
	$op-ldr .$op-jsr .$op-lit         [ LDR ]
	$op-str [ 0000 ] [ 0000 ]         [ STR ]
	$op-jmp [ 0000 ] [ 0000 ]         [ JMP ]
	$op-jnz .$op-gts .$op-ldr         [ JNZ ]
	$op-jsr [ 0000 ] [ 0000 ]         [ JSR ]
	$op-sth .$op-rot .$op-sub         [ STH ]
	$op-add [ 0000 ] .$op-and         [ ADD ]
	$op-sub .$op-str .$op-swp         [ SUB ]
	$op-mul .$op-lts .$op-neq         [ MUL ]
	$op-div [ 0000 ] [ 0000 ]         [ DIV ]
	$op-and [ 0000 ] [ 0000 ]         [ AND ]
	$op-ora [ 0000 ] [ 0000 ]         [ ORA ]
	$op-eor [ 0000 ] [ 0000 ]         [ EOR ]
	$op-sft [ 0000 ] [ 0000 ]         [ SFT ]

@state-machine-pointers
( normal mode 00 )
.normal-root   .normal-main
( macro definition 01 )
.macro-root    .macro-main
( macro definition, contents ignored 02 )
.macro-root    .ignore
( variable definition, expect field size 04 )
.variable-nul  .variable-size
( variable definition, expect field name 08 )
.variable-root .variable-name
( reserved for future use 10 )
[ 0000 ]       .ignore
( literal data 20 )
.normal-]      .data-main
( reserved for future use 40 )
[ 0000 ]       .ignore
( comment 80 )
.normal-)      .ignore

(
	Next up, we have the tree of code corresponding to each token's
	first character. Here we do have a binary payload, which is
	the code to run when the assembler considers the token.

	Some special assembler modes have their own trees. Since comments
	have a very simple tree that only understands the end of comments,
	we reuse the terminal branch of the main tree as the root of
	the comment tree.
)

(
	Left and right parentheses start and end comment sections. They use the
	highest bit in assembler state, so they receive highest priority: it
	doesn't matter what other bits are set, a comment's a comment.
)

@normal-(   [ 0000 ]    .normal-)   [ 28 ]
	~assembler.state #80 ORA =assembler.state
	JMP2r

@normal-)   [ 0000 ]    [ 0000 ]    [ 29 ]
	~assembler.state #7f AND =assembler.state
	JMP2r

(
	Ampersands introduce global labels, and define the scope for any
	local labels that follow.
)

@normal-@   [ 0000 ]    [ 0000 ]    [ 40 ]
	#00 ~assembler.token ,label-tree ,add-label JSR2

	$scope
	~assembler.token ,assembler.scope ,strcpy JSR2
	DUP2 ,assembler.scope SUB2 =assembler.scope-len POP
	#0001 SUB2 #2d SWP POK POP
	JMP2r

(
	Dollar signs introduce local labels, which use the scope defined above.
)

@normal-$   .normal-"   .normal-,   [ 24 ]
	~assembler.token
	,assembler.scope ~assembler.scope-len ADD
	,strcpy JSR2 POP2

	#00 ,assembler.scope ,label-tree ,add-label JMP2 ( tail call )

(
	Hash signs followed by two or four hex digits write a literal.
)

@normal-#   [ 0000 ]    [ 0000 ]    [ 23 ]
	~assembler.token ,parse-hex-string JSR2
	DUP ^$valid JNZ
	( FIXME complain about invalid hex literal )
	POP
	JMP2r
	
	$valid
	DUP #01 SUB SHORT_FLAG MUL ( short flag for opcode )
	,opcodes-op-lit ,opcodes-start SUB2 #07 DIV
	ADD ADD ,write-byte JSR2

	$value
	#02 EQU ^$short JNZ
	,write-byte JMP2 ( tail call )

	$short
	,write-short JMP2 ( tail call )

(
	Left and right square brackets start and end literal data sections.
)

@normal-[   .normal-@   .normal-]   [ 5b ]
	~assembler.state #20 ORA =assembler.state
	JMP2r

@normal-]   [ 0000 ]    [ 0000 ]    [ 5d ]
	( this is spurious, but ignore it anyway )
	JMP2r

@data-]    .normal-(   [ 0000 ]    [ 5d ]
	~assembler.state #df AND =assembler.state
	JMP2r

@data-root
@data-nul  [ 0000 ]    .data-]    [ 00 ]
	JMP2r

@data-main
	~assembler.token ,parse-hex-string JSR2
	DUP ^normal-#-value JNZ
	POP

	~assembler.token
	$loop
	DUP2 PEK2
	DUP ^$keep-going JNZ
	POP POP2 JMP2r

	$keep-going
	,write-byte JSR2
	#0001 ADD2
	^$loop JMP

(
	A pipe moves the current address to the hex value given.
)

@normal-|   .normal-{   .normal-}   [ 7c ]
	~assembler.token ,parse-hex-string JSR2
	DUP #02 EQU ^$valid JNZ
	#00 EQU JMP POP
	( FIXME complain about invalid hex literal )
	JMP2r

	$valid
	POP
	DUP2 ~assembler.addr LTH2 ^$backwards JNZ
	( FIXME add zeroes when writing )
	=assembler.addr
	JMP2r

	$backwards
	( FIXME complain about going backwards )
	POP2
	JMP2r

(
	Commas and dots write the label address - the comma precedes this
	with a LIT2 opcode.
)

@normal-,   .normal-%   .normal-dot [ 2c ]
	,opcodes-op-lit ,opcodes-start SUB2 #07 DIV SHORT_FLAG ADD ,write-byte JSR2 POP
	^normal-dot-main JMP

@normal-dot [ 0000 ]    .normal-;   [ 2e ]
	$main
	~assembler.token ,lookup-label JSR2
	POP ( don't care about node type )
	,write-short JMP2 ( tail call )

(
	Caret writes LIT, followed by the label address as an offset.
)

@normal-^   .normal-[   .normal-|   [ 5e ]
	,opcodes-op-lit ,opcodes-start SUB2 #07 DIV ,write-byte JSR2 POP
	~assembler.token ,lookup-label JSR2
	POP ( don't care about node type )
	~assembler.addr SUB2
	DUP2 #ff79 GTH2 ^$okay JNZ
	DUP2 #0080 LTH2 ^$okay JNZ

	( FIXME complain about jump being too far )

	$okay
	,write-byte JSR2 POP
	JMP2r

(
	Tilde and equals are the load and store helpers respectively.
	If the target is in the zero page, use LDR/PEK or STR/POK opcodes,
	otherwise use LDR2/PEK2 or STR2/POK2 opcodes.
)
@normal-~   [ 0000 ]    [ 0000 ]    [ 7e ]
	LIT2r .opcodes-op-ldr LIT2r .opcodes-op-pek
	^normal-=-main JMP

@normal-root
@normal-=   .normal-$   .normal-^   [ 3d ]
	LIT2r .opcodes-op-str LIT2r .opcodes-op-pok
	$main
	~assembler.token ,lookup-label JSR2
	DUP #03 AND ^$valid JNZ

	( FIXME complain about helper not being usable )
	POP2 JMP2r

	$valid
	#02 AND ^$two-byte JNZ
	SWP2r
	$two-byte
	POP2r
	LIT2r .opcodes-start SUB2r LITr [ 07 ] DIVr
	OVR #00 EQU ^$byte-mode JNZ

	,write-short SHORT_FLAG ^$end JMP

	$byte-mode
	SWP POP
	,write-byte #00

	$end
	,opcodes-op-lit ,opcodes-start SUB2 #07 DIV ADD ADD ,write-byte JSR2
	JSR2
	STHr ,write-byte JSR2
	POPr
	JMP2r

(
	Semicolons introduce variables. The variable name is added to the label
	tree as usual, but all of the subfields are collected into their own tree
	pointed to in the variable name's binary data.
)
@normal-;   [ 0000 ]    [ 0000 ]    [ 3b ]
	#80 ~assembler.token ,label-tree ,add-label JSR2
	~assembler.heap #0000 OVR2 STR2
	DUP2 =assembler.subtree
	#0002 ADD2 =assembler.heap

	~assembler.state #0c ORA =assembler.state
	JMP2r

@variable-root
@variable-{ .variable-nul .variable-} [ 7b ]
	JMP2r

@variable-nul [ 0000 ]    .normal-(   [ 00 ]
	JMP2r

@variable-} [ 0000 ]    [ 0000 ]    [ 7d ]
	~assembler.state #f3 AND =assembler.state
	JMP2r

@variable-name
	#00 ~assembler.token ~assembler.subtree ,add-label JSR2
	~assembler.heap #0003 SUB2 =assembler.vartmp
	~assembler.state #f7 AND =assembler.state
	JMP2r

@variable-size
	~assembler.token ,parse-hex-length JSR2
	^$valid JNZ
	( FIXME complain about invalid size )
	JMP2r

	$valid
	DUP #02 GTH ^$end JNZ
	DUP ~assembler.vartmp POK2
	^$end JMP

	$loop
	#00 ,write-byte JSR2
	#01 SUB
	$end
	DUP ^$loop JNZ
	POP
	~assembler.state #0c ORA =assembler.state
	JMP2r

(
	Percent signs introduce macros. The macro name is added to the macro tree,
	and all the arguments are collected into a list that follows the label's
	binary data.
)
@normal-%   [ 0000 ]    .normal-(   [ 25 ]
	,macro-tree ~assembler.token #ff ,traverse-tree JSR2
	^$new-macro JNZ

	( macro already exists, we assume defined in a previous pass
	  we totally ignore the contents )
	POP2
	~assembler.state #02 ORA =assembler.state
	JMP2r

	$new-macro
	~assembler.token SWP2 ,append-tree JSR2
	POP2
	~assembler.state #01 ORA =assembler.state
	JMP2r

@macro-root
@macro-{   .macro-nul .macro-}   [ 7b ]
	JMP2r

@macro-}   [ 0000 ]    [ 0000 ]    [ 7d ]
	~assembler.heap DUP2 #00 ROT ROT POK2
	#0001 ADD2 =assembler.heap
	~assembler.state #fc AND =assembler.state
	JMP2r

@macro-nul [ 0000 ]    .normal-(   [ 00 ]
	JMP2r

@macro-main
	~assembler.token ,append-heap JSR2
	POP2
	JMP2r


@normal-"   .normal-nul .normal-#   [ 22 ]
	( FIXME NYI )
	JMP2r

@normal-{   [ 0000 ]    [ 0000 ]    [ 7b ]
	( these are spurious, but ignore them anyway )
	JMP2r

@normal-}   [ 0000 ]    .normal-~   [ 7d ]
	( these are spurious, but ignore them anyway )
	JMP2r

@normal-nul [ 0000 ]    [ 0000 ]    [ 00 ]
@ignore
	JMP2r

@normal-main
	~assembler.token
	,opcodes-tree OVR2 #03 ,traverse-tree JSR2
	^$not-opcode JNZ

	,opcodes-asm SUB2 #0007 DIV2
	SWP2 #0003 ADD2
	$flags
	DUP2 PEK2
	DUP #00 EQU ^$end-flags JNZ
	DUP #32 NEQ ^$not-two JNZ
	POP SWP2 SHORT_FLAG ORA SWP2 #0001 ADD2 ^$flags JMP
	$not-two
	DUP #72 NEQ ^$not-r JNZ
	POP SWP2 RETURN_FLAG ORA SWP2 #0001 ADD2 ^$flags JMP
	$not-r
	POP POP2 ~assembler.token SWP2
	^$not-opcode JMP

	$end-flags
	POP POP2
	,write-byte JSR2
	POP
	JMP2r

	$not-opcode
	POP2
	,macro-tree SWP2 #ff ,traverse-tree JSR2
	^$not-macro JNZ
	,assemble-macro JMP2 ( tail call )

	$not-macro
	( FIXME complain about bad opcode / nonexistent macro )
	POP2
	JMP2r

(
	Here's the big set of trees relating to labels. Starting from l-root, all
	the devices are stored here, perhaps some helper functions in the future,
	too.

	left-node* right-node* node-key-cstring binary-data

	The node-keys are terminated with NUL since, unlike the opcodes and first
	characters, the keys are variable length.

	The binary-data is either three or five bytes long:
		flags value* [ subtree-pointer* ]

	The flags byte is divided up into bits:

	bit 0-1: 00 means store / load helpers cannot be used,
	         01 means the helpers use POK / PEK,
	         02 means the helpers use STR / LDR,
	         03 is invalid;
	bits 2-6 are reserved; and
	bit 7: 80 means there is a subtree.

	If there is a subtree, it is searched when the reference contains a dot.
)

@l-Audio           [ 0000 ]          [ 0000 ]         [ Audio 00 ]      [ 80 ] .Audio .l-Audio-root
@l-Audio-delay     [ 0000 ]          [ 0000 ]         [ delay 00 ]      [ 02 ] .Audio.delay
@l-Audio-envelope .l-Audio-delay    .l-Audio-finish   [ envelope 00 ]   [ 02 ] .Audio.envelope
@l-Audio-finish    [ 0000 ]          [ 0000 ]         [ finish 00 ]     [ 01 ] .Audio.finish
@l-Audio-root
@l-Audio-pitch    .l-Audio-envelope .l-Audio-value    [ pitch 00 ]      [ 01 ] .Audio.pitch
@l-Audio-play      [ 0000 ]          [ 0000 ]         [ play 00 ]       [ 01 ] .Audio.play
@l-Audio-value    .l-Audio-play     .l-Audio-volume   [ value 00 ]      [ 02 ] .Audio.value
@l-Audio-volume    [ 0000 ]         .l-Audio-wave     [ volume 00 ]     [ 01 ] .Audio.volume
@l-Audio-wave      [ 0000 ]          [ 0000 ]         [ wave 00 ]       [ 02 ] .Audio.wave
@l-Console        .l-Audio          .l-Controller     [ Console 00 ]    [ 80 ] .Console .l-Console-root
@l-Console-byte    [ 0000 ]         .l-Console-char   [ byte 00 ]       [ 01 ] .Console.byte
@l-Console-char    [ 0000 ]          [ 0000 ]         [ char 00 ]       [ 01 ] .Console.char
@l-Console-root
@l-Console-short  .l-Console-byte   .l-Console-string [ short 00 ]      [ 02 ] .Console.short
@l-Console-string  [ 0000 ]         .l-Console-vector [ string 00 ]     [ 02 ] .Console.string
@l-Console-vector  [ 0000 ]          [ 0000 ]         [ vector 00 ]     [ 02 ] .Console.vector
@l-Controller      [ 0000 ]          [ 0000 ]         [ Controller 00 ] [ 80 ] .Controller .l-Controller-root
@l-Controller-button  [ 0000 ]          [ 0000 ]         [ button 00 ]     [ 01 ] .Controller.button
@l-Controller-root
@l-Controller-key .l-Controller-button .l-Controller-vector [ key 00 ]        [ 01 ] .Controller.key
@l-Controller-vector  [ 0000 ]          [ 0000 ]         [ vector 00 ]     [ 02 ] .Controller.vector
@l-root
@l-DateTime       .l-Console        .l-Mouse          [ DateTime 00 ]   [ 80 ] .DateTime .l-DateTime-root
@l-DateTime-day    [ 0000 ]          [ 0000 ]         [ day 00 ]        [ 01 ] .DateTime.day
@l-DateTime-dotw  .l-DateTime-day   .l-DateTime-doty  [ dotw 00 ]       [ 01 ] .DateTime.dotw
@l-DateTime-doty   [ 0000 ]         .l-DateTime-hour  [ doty 00 ]       [ 02 ] .DateTime.doty
@l-DateTime-hour   [ 0000 ]          [ 0000 ]         [ hour 00 ]       [ 01 ] .DateTime.hour
@l-DateTime-root
@l-DateTime-isdst .l-DateTime-dotw  .l-DateTime-refresh [ isdst 00 ]      [ 01 ] .DateTime.isdst
@l-DateTime-minute  [ 0000 ]         .l-DateTime-month [ minute 00 ]     [ 01 ] .DateTime.minute
@l-DateTime-month  [ 0000 ]          [ 0000 ]         [ month 00 ]      [ 01 ] .DateTime.month
@l-DateTime-refresh .l-DateTime-minute .l-DateTime-second [ refresh 00 ]    [ 01 ] .DateTime.refresh
@l-DateTime-second  [ 0000 ]         .l-DateTime-year  [ second 00 ]     [ 01 ] .DateTime.second
@l-DateTime-year   [ 0000 ]          [ 0000 ]         [ year 00 ]       [ 02 ] .DateTime.year
@l-File            [ 0000 ]          [ 0000 ]         [ File 00 ]       [ 80 ] .File .l-File-root
@l-File-length     [ 0000 ]         .l-File-load      [ length 00 ]     [ 02 ] .File.length
@l-File-load       [ 0000 ]          [ 0000 ]         [ load 00 ]       [ 02 ] .File.load
@l-File-root
@l-File-name      .l-File-length    .l-File-save      [ name 00 ]       [ 02 ] .File.name
@l-File-save       [ 0000 ]         .l-File-vector    [ save 00 ]       [ 02 ] .File.save
@l-File-vector     [ 0000 ]          [ 0000 ]         [ vector 00 ]     [ 02 ] .File.vector
@l-Mouse          .l-File           .l-Screen         [ Mouse 00 ]      [ 80 ] .Mouse .l-Mouse-root
@l-Mouse-chord     [ 0000 ]         .l-Mouse-state    [ chord 00 ]      [ 01 ] .Mouse.chord
@l-Mouse-state     [ 0000 ]          [ 0000 ]         [ state 00 ]      [ 01 ] .Mouse.state
@l-Mouse-root
@l-Mouse-vector   .l-Mouse-chord    .l-Mouse-x        [ vector 00 ]     [ 02 ] .Mouse.vector
@l-Mouse-x         [ 0000 ]         .l-Mouse-y        [ x 00 ]          [ 02 ] .Mouse.x
@l-Mouse-y         [ 0000 ]          [ 0000 ]         [ y 00 ]          [ 02 ] .Mouse.y
@l-Screen          [ 0000 ]         .l-System         [ Screen 00 ]     [ 80 ] .Screen .l-Screen-root
@l-Screen-addr     [ 0000 ]          [ 0000 ]         [ addr 00 ]       [ 02 ] .Screen.addr
@l-Screen-color   .l-Screen-addr    .l-Screen-height  [ color 00 ]      [ 01 ] .Screen.color
@l-Screen-height   [ 0000 ]          [ 0000 ]         [ height 00 ]     [ 02 ] .Screen.height
@l-Screen-root
@l-Screen-vector  .l-Screen-color   .l-Screen-x       [ vector 00 ]     [ 02 ] .Screen.vector
@l-Screen-width    [ 0000 ]          [ 0000 ]         [ width 00 ]      [ 02 ] .Screen.width
@l-Screen-x       .l-Screen-width   .l-Screen-y       [ x 00 ]          [ 02 ] .Screen.x
@l-Screen-y        [ 0000 ]          [ 0000 ]         [ y 00 ]          [ 02 ] .Screen.y
@l-System          [ 0000 ]          [ 0000 ]         [ System 00 ]     [ 80 ] .System .l-System-root
@l-System-b        [ 0000 ]          [ 0000 ]         [ b 00 ]          [ 02 ] .System.b
@l-System-root
@l-System-g       .l-System-b       .l-System-r       [ g 00 ]          [ 02 ] .System.g
@l-System-r        [ 0000 ]         .l-System-vector  [ r 00 ]          [ 02 ] .System.r
@l-System-vector   [ 0000 ]          [ 0000 ]         [ vector 00 ]     [ 02 ] .System.vector

@assembler-heap-start