7 size_RS = 1024 # Return stack size
8 size_PS = 1024 # Parameter stack size
9 size_TIB = 1096 # Terminal input buffer size
11 # The mem array constitutes the memory of the VM. It has the following geography:
13 # mem = +-----------------------+
14 # | Built-in Variables |
15 # +-----------------------+
17 # +-----------------------+
19 # +-----------------------+
20 # | Terminal Input Buffer |
21 # +-----------------------+
23 # +-----------------------+
25 # Note that all words (user-defined, primitive, variables, etc) are included in
28 # Simple linear addressing is used with one exception: references to primitive code
29 # blocks, which are represented as anonymous functions, appear as negative indicies
30 # into the primitives array which contains these functions.
32 mem = Array{Int64,1}(size_mem)
33 primitives = Array{Function,1}()
34 primNames = Array{ASCIIString,1}()
39 RSP0 = nextVarAddr; nextVarAddr += 1
40 PSP0 = nextVarAddr; nextVarAddr += 1
41 HERE = nextVarAddr; nextVarAddr += 1
42 LATEST = nextVarAddr; nextVarAddr += 1
44 mem[RSP0] = nextVarAddr # bottom of RS
45 mem[PSP0] = mem[RSP0] + size_RS # bottom of PS
46 TIB = mem[PSP0] + size_PS # address of terminal input buffer
47 mem[HERE] = TIB + size_TIB # location of bottom of dictionary
48 mem[LATEST] = 0 # no previous definition
50 DICT = mem[HERE] # Save bottom of dictionary as constant
54 RSP::Int64 # Return stack pointer
55 PSP::Int64 # Parameter/data stack pointer
56 IP::Int64 # Instruction pointer
57 W::Int64 # Working register
59 source::Any # Input stream in use
61 reg = Reg(mem[RSP0], mem[PSP0], 0, 0, STDIN)
63 # Stack manipulation functions
65 type StackUnderflow <: Exception end
67 getRSDepth() = reg.RSP - mem[RSP0]
68 getPSDepth() = reg.PSP - mem[PSP0]
70 function ensurePSDepth(depth::Int64)
72 throw(StackUnderflow())
76 function ensureRSDepth(depth::Int64)
78 throw(StackUnderflow())
82 function pushRS(val::Int64)
94 function pushPS(val::Int64)
95 mem[reg.PSP += 1] = val
106 # Handy functions for adding/retrieving strings to/from memory.
108 getString(addr::Int64, len::Int64) = ASCIIString([Char(c) for c in mem[addr:(addr+len-1)]])
109 function putString(str::ASCIIString, addr::Int64)
110 mem[addr:(addr+length(str)-1)] = [Int64(c) for c in str]
113 # Primitive creation and calling functions
115 function defPrim(f::Function; name="nameless")
117 push!(primNames, name)
119 return -length(primitives)
122 callPrim(addr::Int64) = primitives[-addr]()
126 function createHeader(name::AbstractString, flags::Int64)
127 mem[mem[HERE]] = mem[LATEST]
128 mem[LATEST] = mem[HERE]
131 mem[mem[HERE]] = length(name) | flags; mem[HERE] += 1
132 putString(name, mem[HERE]); mem[HERE] += length(name)
135 function defPrimWord(name::AbstractString, f::Function; flags::Int64=0)
136 createHeader(name, flags)
138 codeWordAddr = mem[HERE]
139 mem[codeWordAddr] = defPrim(f, name=name)
145 function defWord(name::AbstractString, wordAddrs::Array{Int64,1}; flags::Int64=0)
146 createHeader(name, flags)
149 mem[mem[HERE]] = DOCOL
152 for wordAddr in wordAddrs
153 mem[mem[HERE]] = wordAddr
162 function defExistingVar(name::AbstractString, varAddr::Int64; flags::Int64=0)
164 defPrimWord(name, eval(:(() -> begin
170 function defNewVar(name::AbstractString, initial::Int64; flags::Int64=0)
171 createHeader(name, flags)
173 codeWordAddr = mem[HERE]
174 varAddr = mem[HERE] + 1
176 f = eval(:(() -> begin
181 mem[mem[HERE]] = defPrim(f, name=name); mem[HERE] += 1
182 mem[mem[HERE]] = initial; mem[HERE] += 1
184 return varAddr, codeWordAddr
187 function defConst(name::AbstractString, val::Int64; flags::Int64=0)
188 defPrimWord(name, eval(:(() -> begin
196 # Threading Primitives (inner interpreter)
198 NEXT = defPrim(() -> begin
204 DOCOL = defPrim(() -> begin
210 EXIT = defPrimWord("EXIT", () -> begin
215 # Basic forth primitives
217 DROP = defPrimWord("DROP", () -> begin
222 SWAP = defPrimWord("SWAP", () -> begin
230 DUP = defPrimWord("DUP", () -> begin
235 OVER = defPrimWord("OVER", () -> begin
237 pushPS(mem[reg.PSP-1])
241 ROT = defPrimWord("ROT", () -> begin
251 NROT = defPrimWord("-ROT", () -> begin
261 TWODROP = defPrimWord("2DROP", () -> begin
267 TWODUP = defPrimWord("2DUP", () -> begin
276 TWOSWAP = defPrimWord("2SWAP", () -> begin
288 QDUP = defPrimWord("?DUP", () -> begin
297 INCR = defPrimWord("1+", () -> begin
303 DECR = defPrimWord("1-", () -> begin
309 INCR2 = defPrimWord("2+", () -> begin
315 DECR2 = defPrimWord("2-", () -> begin
321 ADD = defPrimWord("+", () -> begin
328 SUB = defPrimWord("-", () -> begin
335 MUL = defPrimWord("*", () -> begin
342 DIVMOD = defPrimWord("/MOD", () -> begin
351 EQU = defPrimWord("=", () -> begin
354 pushPS(a==b ? -1 : 0)
358 NEQU = defPrimWord("<>", () -> begin
361 pushPS(a!=b ? -1 : 0)
365 LT = defPrimWord("<", () -> begin
372 GT = defPrimWord(">", () -> begin
379 LE = defPrimWord("<=", () -> begin
382 pushPS(a<=b ? -1 : 0)
386 GE = defPrimWord(">=", () -> begin
389 pushPS(a>=b ? -1 : 0)
393 ZEQU = defPrimWord("0=", () -> begin
394 pushPS(popPS() == 0 ? -1 : 0)
398 ZNEQU = defPrimWord("0<>", () -> begin
399 pushPS(popPS() != 0 ? -1 : 0)
403 ZLT = defPrimWord("0<", () -> begin
404 pushPS(popPS() < 0 ? -1 : 0)
408 ZGT = defPrimWord("0>", () -> begin
409 pushPS(popPS() > 0 ? -1 : 0)
413 ZLE = defPrimWord("0<=", () -> begin
414 pushPS(popPS() <= 0 ? -1 : 0)
418 ZGE = defPrimWord("0>=", () -> begin
419 pushPS(popPS() >= 0 ? -1 : 0)
423 AND = defPrimWord("AND", () -> begin
430 OR = defPrimWord("OR", () -> begin
437 XOR = defPrimWord("XOR", () -> begin
444 INVERT = defPrimWord("INVERT", () -> begin
451 LIT = defPrimWord("LIT", () -> begin
459 STORE = defPrimWord("!", () -> begin
466 FETCH = defPrimWord("@", () -> begin
472 ADDSTORE = defPrimWord("+!", () -> begin
479 SUBSTORE = defPrimWord("-!", () -> begin
489 HERE_CFA = defExistingVar("HERE", HERE)
490 LATEST_CFA = defExistingVar("LATEST", LATEST)
491 PSP0_CFA = defExistingVar("PSP0", PSP0)
492 RSP0_CFA = defExistingVar("RSP0", RSP0)
493 STATE, STATE_CFA = defNewVar("STATE", 0)
494 BASE, BASE_CFA = defNewVar("BASE", 10)
498 defConst("VERSION", 1)
499 defConst("DOCOL", DOCOL)
500 defConst("DICT", DICT)
501 F_IMMED = defConst("F_IMMED", 128)
502 F_HIDDEN = defConst("F_HIDDEN", 256)
503 F_LENMASK = defConst("F_LENMASK", 127)
507 TOR = defPrimWord(">R", () -> begin
512 FROMR = defPrimWord("R>", () -> begin
517 RSPFETCH = defPrimWord("RSP@", () -> begin
522 RSPSTORE = defPrimWord("RSP!", () -> begin
527 RDROP = defPrimWord("RDROP", () -> begin
534 PSPFETCH = defPrimWord("PSP@", () -> begin
539 PSPSTORE = defPrimWord("PSP!", () -> begin
546 WFETCH = defPrimWord("W@", () -> begin
551 WSTORE = defPrimWord("W!", () -> begin
559 NUMTIB, NUMTIB_CFA = defNewVar("#TIB", 0)
560 TOIN, TOIN_CFA = defNewVar(">IN", 0)
562 KEY = defPrimWord("KEY", () -> begin
563 if mem[TOIN] >= mem[NUMTIB]
566 if reg.source != STDIN && eof(reg.source)
570 line = readline(reg.source)
571 mem[NUMTIB] = length(line)
575 pushPS(mem[TIB + mem[TOIN]])
581 EMIT = defPrimWord("EMIT", () -> begin
586 WORD = defPrimWord("WORD", () -> begin
608 if c == ' ' || c == '\t'
619 # Treat newline as a special word
621 mem[wordAddr + offset] = Int64(c)
628 mem[wordAddr + offset] = Int64(c)
634 if c == ' ' || c == '\t' || c == '\n'
649 NUMBER = defPrimWord("NUMBER", () -> begin
654 s = getString(wordAddr, wordLen)
657 pushPS(parse(Int64, s, mem[BASE]))
660 pushPS(1) # Error indication
666 # Dictionary searches
668 FIND = defPrimWord("FIND", () -> begin
672 word = lowercase(getString(wordAddr, wordLen))
677 while (latest = mem[latest]) > 0
678 lenAndFlags = mem[latest+1]
679 len = lenAndFlags & F_LENMASK
680 hidden = (lenAndFlags & F_HIDDEN) == F_HIDDEN
682 if hidden || len != wordLen
687 thisWord = lowercase(getString(thisAddr, len))
689 if lowercase(thisWord) == lowercase(word)
699 TOCFA = defPrimWord(">CFA", () -> begin
702 lenAndFlags = mem[addr+1]
703 len = lenAndFlags & F_LENMASK
705 pushPS(addr + 2 + len)
710 TODFA = defWord(">DFA", [TOCFA, INCR, EXIT])
714 CREATE = defPrimWord("CREATE", () -> begin
718 word = getString(wordAddr, wordLen)
720 createHeader(word, 0)
725 COMMA = defPrimWord(",", () -> begin
726 mem[mem[HERE]] = popPS()
732 LBRAC = defPrimWord("[", () -> begin
737 RBRAC = defPrimWord("]", () -> begin
742 HIDDEN = defPrimWord("HIDDEN", () -> begin
744 mem[addr] = mem[addr] $ F_HIDDEN
748 HIDE = defWord("HIDE",
758 LATEST_CFA, FETCH, HIDDEN,
762 SEMICOLON = defWord(";",
764 LATEST_CFA, FETCH, HIDDEN,
766 EXIT], flags=F_IMMED)
768 IMMEDIATE = defPrimWord("IMMEDIATE", () -> begin
769 lenAndFlagsAddr = mem[LATEST] + 1
770 mem[lenAndFlagsAddr] = mem[lenAndFlagsAddr] $ F_IMMED
774 TICK = defWord("'", [WORD, FIND, TOCFA, EXIT])
778 BRANCH = defPrimWord("BRANCH", () -> begin
779 reg.IP += mem[reg.IP]
783 ZBRANCH = defPrimWord("0BRANCH", () -> begin
785 reg.IP += mem[reg.IP]
795 LITSTRING = defPrimWord("LITSTRING", () -> begin
805 TELL = defPrimWord("TELL", () -> begin
808 str = getString(addr, len)
815 EXECUTE = defPrimWord("EXECUTE", () -> begin
820 INTERPRET = defPrimWord("INTERPRET", () -> begin
824 wordName = getString(mem[reg.PSP-1], mem[reg.PSP])
825 #println("... ", replace(wordName, "\n", "\\n"), " ...")
827 callPrim(mem[TWODUP])
830 wordAddr = mem[reg.PSP]
835 isImmediate = (mem[wordAddr+1] & F_IMMED) != 0
838 callPrim(mem[ROT]) # get rid of extra copy of word string details
842 if mem[STATE] == 0 || isImmediate
844 #println("Executing CFA at $(mem[reg.PSP])")
845 return callPrim(mem[EXECUTE])
847 # Append CFA to dictionary
851 # Not in dictionary, assume number
855 callPrim(mem[NUMBER])
858 println("Parse error at word: '$wordName'")
863 # Number already on stack!
865 # Append literal to dictionary
875 QUIT = defWord("QUIT",
880 BYE = defPrimWord("BYE", () -> begin
884 NL = defPrimWord("\n", () -> begin
885 if mem[STATE] == 0 && reg.source == STDIN
893 CHAR = defPrimWord("CHAR", () -> begin
897 word = getString(wordAddr, wordLen)
898 pushPS(Int64(word[1]))
903 INCLUDE = defPrimWord("INCLUDE", () -> begin
908 word = getString(wordAddr, wordLen)
910 println("Reading from $word...")
912 reg.source = open(word, "r")
922 # Start with IP pointing to first instruction of outer interpreter
925 # Primitive processing loop.
926 # Everyting else is simply a consequence of this loop!
928 while (jmp = callPrim(jmp)) != 0
929 #println("Evaluating prim $jmp [$(primNames[-jmp])]")
935 function dump(startAddr::Int64; count::Int64 = 100, cellsPerLine::Int64 = 10)
936 chars = Array{Char,1}(cellsPerLine)
938 lineStartAddr = cellsPerLine*div((startAddr-1),cellsPerLine) + 1
939 endAddr = startAddr + count - 1
941 q, r = divrem((endAddr-lineStartAddr+1), cellsPerLine)
942 numLines = q + (r > 0 ? 1 : 0)
948 for c in 1:cellsPerLine
949 if i >= startAddr && i <= endAddr
951 if mem[i]>=32 && mem[i]<128
952 chars[c] = Char(mem[i])
964 println("\t", ASCIIString(chars))
969 count = reg.PSP - mem[PSP0]
973 for i in (mem[PSP0]+1):reg.PSP
978 println("Parameter stack empty")
983 count = reg.RSP - mem[RSP0]
987 for i in (mem[RSP0]+1):reg.RSP
992 println("Return stack empty")