4 size_mem = 1000000 # 1 mega-int
7 size_RS = 1000 # Return stack size
8 size_PS = 1000 # Parameter stack size
9 size_TIB = 1000 # 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 H = nextVarAddr; nextVarAddr += 1
40 LATEST = nextVarAddr; nextVarAddr += 1
42 RSP0 = nextVarAddr # bottom of RS
43 PSP0 = RSP0 + size_RS # bottom of PS
44 TIB = PSP0 + size_PS # address of terminal input buffer
45 mem[H] = TIB + size_TIB # location of bottom of dictionary
46 mem[LATEST] = 0 # no previous definition
48 DICT = mem[H] # Save bottom of dictionary as constant
52 RSP::Int64 # Return stack pointer
53 PSP::Int64 # Parameter/data stack pointer
54 IP::Int64 # Instruction pointer
55 W::Int64 # Working register
57 reg = Reg(RSP0, PSP0, 0, 0)
59 # Stack manipulation functions
61 type ParamStackUnderflow <: Exception end
62 type ReturnStackUnderflow <: Exception end
64 Base.showerror(io::IO, ex::ParamStackUnderflow) = print(io, "Parameter stack underflow.")
65 Base.showerror(io::IO, ex::ReturnStackUnderflow) = print(io, "Return stack underflow.")
67 getRSDepth() = reg.RSP - RSP0
68 getPSDepth() = reg.PSP - PSP0
70 function ensurePSDepth(depth::Int64)
72 throw(ParamStackUnderflow())
76 function ensureRSDepth(depth::Int64)
78 throw(ReturnStackUnderflow())
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)]])
110 function putString(str::ASCIIString, addr::Int64)
111 mem[addr:(addr+length(str)-1)] = [Int64(c) for c in str]
114 # Primitive creation and calling functions
116 function defPrim(f::Function; name="nameless")
118 push!(primNames, replace(name, "\004", "EOF"))
120 return -length(primitives)
123 function callPrim(addr::Int64)
124 if addr >=0 || -addr>length(primitives)
125 error("Attempted to execute non-existent primitive at address $addr.")
130 getPrimName(addr::Int64) = primNames[-addr]
132 # Word creation functions
139 function createHeader(name::AbstractString, flags::Int64)
140 mem[mem[H]] = mem[LATEST]
144 mem[mem[H]] = length(name) | flags | NFA_MARK; mem[H] += 1
145 putString(name, mem[H]); mem[H] += length(name)
148 function defPrimWord(name::AbstractString, f::Function; flags::Int64=0)
149 createHeader(name, flags)
151 codeWordAddr = mem[H]
152 mem[codeWordAddr] = defPrim(f, name=name)
158 function defWord(name::AbstractString, wordAddrs::Array{Int64,1}; flags::Int64=0)
159 createHeader(name, flags)
165 for wordAddr in wordAddrs
166 mem[mem[H]] = wordAddr
173 # Variable creation functions
175 function defExistingVar(name::AbstractString, varAddr::Int64; flags::Int64=0)
177 defPrimWord(name, eval(:(() -> begin
183 function defNewVar(name::AbstractString, initial::Int64; flags::Int64=0)
184 createHeader(name, flags)
186 codeWordAddr = mem[H]
189 mem[mem[H]] = DOVAR; mem[H] += 1
190 mem[mem[H]] = initial; mem[H] += 1
192 return varAddr, codeWordAddr
195 function defConst(name::AbstractString, val::Int64; flags::Int64=0)
196 createHeader(name, flags)
198 codeWordAddr = mem[H]
200 mem[mem[H]] = DOCON; mem[H] += 1
201 mem[mem[H]] = val; mem[H] += 1
206 # Threading Primitives (inner interpreter)
208 NEXT = defPrim(() -> begin
214 DOCOL = defPrim(() -> begin
220 DOVAR = defPrim(() -> begin
225 DOCON = defPrim(() -> begin
226 pushPS(mem[reg.W + 1])
230 EXIT = defPrimWord("EXIT", () -> begin
235 # Dictionary entries for core built-in variables, constants
237 H_CFA = defExistingVar("H", H)
238 LATEST_CFA = defExistingVar("LATEST", LATEST)
240 PSP0_CFA = defConst("PSP0", PSP0)
241 RSP0_CFA = defConst("RSP0", RSP0)
243 defConst("DOCOL", DOCOL)
244 defConst("DOCON", DOCON)
245 defConst("DOVAR", DOVAR)
247 defConst("DICT", DICT)
248 defConst("MEMSIZE", size_mem)
250 F_IMMED_CFA = defConst("F_IMMED", F_IMMED)
251 F_HIDDEN_CFA = defConst("F_HIDDEN", F_HIDDEN)
252 F_LENMASK_CFA = defConst("F_LENMASK", F_LENMASK)
253 NFA_MARK_CFA = defConst("NFA_MARK", NFA_MARK)
255 # Basic forth primitives
257 DROP = defPrimWord("DROP", () -> begin
262 SWAP = defPrimWord("SWAP", () -> begin
270 DUP = defPrimWord("DUP", () -> begin
276 OVER = defPrimWord("OVER", () -> begin
278 pushPS(mem[reg.PSP-1])
282 ROT = defPrimWord("ROT", () -> begin
292 NROT = defPrimWord("-ROT", () -> begin
303 TWODROP = defPrimWord("2DROP", () -> begin
309 TWODUP = defPrimWord("2DUP", () -> begin
318 TWOSWAP = defPrimWord("2SWAP", () -> begin
330 TWOOVER = defPrimWord("2OVER", () -> begin
339 QDUP = defPrimWord("?DUP", () -> begin
348 INCR = defPrimWord("1+", () -> begin
354 DECR = defPrimWord("1-", () -> begin
360 INCR2 = defPrimWord("2+", () -> begin
366 DECR2 = defPrimWord("2-", () -> begin
372 ADD = defPrimWord("+", () -> begin
379 SUB = defPrimWord("-", () -> begin
386 MUL = defPrimWord("*", () -> begin
393 DIVMOD = defPrimWord("/MOD", () -> begin
402 TWOMUL = defPrimWord("2*", () -> begin
407 TWODIV = defPrimWord("2/", () -> begin
412 EQ = defPrimWord("=", () -> begin
415 pushPS(a==b ? -1 : 0)
419 NE = defPrimWord("<>", () -> begin
422 pushPS(a!=b ? -1 : 0)
426 LT = defPrimWord("<", () -> begin
433 GT = defPrimWord(">", () -> begin
440 LE = defPrimWord("<=", () -> begin
443 pushPS(a<=b ? -1 : 0)
447 GE = defPrimWord(">=", () -> begin
450 pushPS(a>=b ? -1 : 0)
454 ZE = defPrimWord("0=", () -> begin
455 pushPS(popPS() == 0 ? -1 : 0)
459 ZNE = defPrimWord("0<>", () -> begin
460 pushPS(popPS() != 0 ? -1 : 0)
464 ZLT = defPrimWord("0<", () -> begin
465 pushPS(popPS() < 0 ? -1 : 0)
469 ZGT = defPrimWord("0>", () -> begin
470 pushPS(popPS() > 0 ? -1 : 0)
474 ZLE = defPrimWord("0<=", () -> begin
475 pushPS(popPS() <= 0 ? -1 : 0)
479 ZGE = defPrimWord("0>=", () -> begin
480 pushPS(popPS() >= 0 ? -1 : 0)
484 AND = defPrimWord("AND", () -> begin
491 OR = defPrimWord("OR", () -> begin
498 XOR = defPrimWord("XOR", () -> begin
505 INVERT = defPrimWord("INVERT", () -> begin
512 LIT = defPrimWord("LIT", () -> begin
520 STORE = defPrimWord("!", () -> begin
527 FETCH = defPrimWord("@", () -> begin
533 ADDSTORE = defPrimWord("+!", () -> begin
540 SUBSTORE = defPrimWord("-!", () -> begin
550 TOR = defPrimWord(">R", () -> begin
555 FROMR = defPrimWord("R>", () -> begin
560 RFETCH = defPrimWord("R@", () -> begin
565 RSPFETCH = defPrimWord("RSP@", () -> begin
570 RSPSTORE = defPrimWord("RSP!", () -> begin
575 RDROP = defPrimWord("RDROP", () -> begin
582 PSPFETCH = defPrimWord("PSP@", () -> begin
587 PSPSTORE = defPrimWord("PSP!", () -> begin
594 WFETCH = defPrimWord("W@", () -> begin
599 WSTORE = defPrimWord("W!", () -> begin
606 sources = Array{Any,1}()
607 currentSource() = sources[length(sources)]
609 EOF = defPrimWord("\x04", () -> begin
618 EMIT = defPrimWord("EMIT", () -> begin
623 SPAN, SPAN_CFA = defNewVar("SPAN", 0)
624 EXPECT = defPrimWord("EXPECT", () -> begin
628 if !eof(currentSource())
629 line = chomp(readline(currentSource()))
630 mem[SPAN] = min(length(line), maxLen)
631 putString(line[1:mem[SPAN]], addr)
640 BASE, BASE_CFA = defNewVar("BASE", 10)
641 NUMBER = defPrimWord("NUMBER", () -> begin
643 wordLen = mem[wordAddr-1]
645 s = getString(wordAddr, wordLen)
647 pushPS(parse(Int64, s, mem[BASE]))
652 # Dictionary searches
654 TOCFA = defPrimWord(">CFA", () -> begin
657 lenAndFlags = mem[addr+1]
658 len = lenAndFlags & F_LENMASK
660 pushPS(addr + 2 + len)
665 TOBODY = defWord(">BODY", [INCR, EXIT])
667 FIND = defPrimWord("FIND", () -> begin
669 countedAddr = popPS()
670 wordAddr = countedAddr + 1
671 wordLen = mem[countedAddr]
672 word = lowercase(getString(wordAddr, wordLen))
678 while (latest = mem[latest]) > 0
679 lenAndFlags = mem[latest+1]
680 len = lenAndFlags & F_LENMASK
681 hidden = (lenAndFlags & F_HIDDEN) == F_HIDDEN
683 if hidden || len != wordLen
688 thisWord = lowercase(getString(thisAddr, len))
690 if lowercase(thisWord) == lowercase(word)
698 if (lenAndFlags & F_IMMED) == F_IMMED
714 BRANCH = defPrimWord("BRANCH", () -> begin
715 reg.IP += mem[reg.IP]
719 ZBRANCH = defPrimWord("0BRANCH", () -> begin
721 reg.IP += mem[reg.IP]
731 LITSTRING = defPrimWord("LITSTRING", () -> begin
741 TYPE = defPrimWord("TYPE", () -> begin
744 str = getString(addr, len)
751 TRACE = defPrimWord("TRACE", () -> begin
752 println("reg.W: $(reg.W) reg.IP: $(reg.IP)")
753 print("PS: "); printPS()
754 print("RS: "); printRS()
761 COMMA = defPrimWord(",", () -> begin
762 mem[mem[H]] = popPS()
768 BTICK = defWord("[']",
769 [FROMR, DUP, INCR, TOR, FETCH, EXIT])
771 EXECUTE = defPrimWord("EXECUTE", () -> begin
776 TIB_CFA = defConst("TIB", TIB)
777 NUMTIB, NUMTIB_CFA = defNewVar("#TIB", 0)
778 TOIN, TOIN_CFA = defNewVar(">IN", 0)
780 QUERY = defWord("QUERY",
781 [TIB_CFA, LIT, 160, EXPECT,
782 SPAN_CFA, FETCH, NUMTIB_CFA, STORE,
783 LIT, 0, TOIN_CFA, STORE,
786 WORD = defPrimWord("WORD", () -> begin
789 # Chew up initial occurrences of delim
790 while (mem[TOIN]<mem[NUMTIB] && mem[TIB+mem[TOIN]] == delim)
797 # Start reading in word
799 while (mem[TOIN]<mem[NUMTIB])
800 mem[addr] = mem[TIB+mem[TOIN]]
803 if (mem[addr] == delim)
812 mem[countAddr] = count
818 PARSE = defPrimWord("PARSE", () -> begin
821 # Chew up initial occurrences of delim
824 # Start reading input stream
826 while (mem[TOIN]<mem[NUMTIB])
827 mem[addr] = mem[TIB+mem[TOIN]]
830 if (mem[addr] == delim)
844 BYE = defPrimWord("BYE", () -> begin
849 STATE, STATE_CFA = defNewVar("STATE", 0)
851 INTERPRET = defWord("INTERPRET",
852 [LIT, 32, WORD, # Read next space-delimited word
854 DUP, FETCH, ZE, ZBRANCH, 3,
855 DROP, EXIT, # Exit if TIB is exhausted
857 STATE_CFA, FETCH, ZBRANCH, 24,
859 FIND, QDUP, ZBRANCH, 13,
862 LIT, -1, EQ, INVERT, ZBRANCH, 4,
864 # Immediate: Execute!
865 EXECUTE, BRANCH, -26,
867 # Not immediate: Compile!
870 # No word found, parse number
871 NUMBER, BTICK, LIT, COMMA, COMMA, BRANCH, -36,
874 FIND, QDUP, ZBRANCH, 5,
876 # Found word. Execute!
877 DROP, EXECUTE, BRANCH, -44,
879 # No word found, parse number and leave on stack
884 PROMPT = defPrimWord("PROMPT", () -> begin
885 if (mem[STATE] == 0 && currentSource() == STDIN)
892 QUIT = defWord("QUIT",
893 [LIT, 0, STATE_CFA, STORE,
894 LIT, 0, NUMTIB_CFA, STORE,
900 ABORT = defWord("ABORT",
901 [PSP0_CFA, PSPSTORE, QUIT])
903 INCLUDE = defPrimWord("INCLUDE", () -> begin
907 wordLen = mem[wordAddr-1]
908 word = getString(wordAddr, wordLen)
910 push!(sources, open(word, "r"))
920 HERE = defWord("HERE",
921 [H_CFA, FETCH, EXIT])
923 HEADER = defPrimWord("HEADER", () -> begin
925 wordLen = mem[wordAddr-1]
926 word = getString(wordAddr, wordLen)
928 createHeader(word, 0)
933 CREATE = defWord("CREATE",
934 [LIT, 32, WORD, HEADER,
938 DODOES = defPrim(() -> begin
945 DOES_HELPER = defPrimWord("(DOES>)", () -> begin
951 runtimeAddr = popPS()
953 mem[cfa] = defPrim(eval(:(() -> begin
954 pushPS($(runtimeAddr))
956 end)), name="doesPrim")
961 DOES = defWord("DOES>",
962 [BTICK, LIT, COMMA, HERE, LIT, 3, ADD, COMMA,
963 BTICK, DOES_HELPER, COMMA, BTICK, EXIT, COMMA, EXIT],
966 LBRAC = defPrimWord("[", () -> begin
971 RBRAC = defPrimWord("]", () -> begin
976 HIDDEN = defPrimWord("HIDDEN", () -> begin
977 lenAndFlagsAddr = mem[LATEST] + 1
978 mem[lenAndFlagsAddr] = mem[lenAndFlagsAddr] $ F_HIDDEN
990 SEMICOLON = defWord(";",
994 EXIT], flags=F_IMMED)
996 IMMEDIATE = defPrimWord("IMMEDIATE", () -> begin
997 lenAndFlagsAddr = mem[LATEST] + 1
998 mem[lenAndFlagsAddr] = mem[lenAndFlagsAddr] $ F_IMMED
1006 initFileName = nothing
1007 if isfile("lib.4th")
1008 initFileName = "lib.4th"
1009 elseif isfile(Pkg.dir("forth/src/lib.4th"))
1010 initFileName = Pkg.dir("forth/src/lib.4th")
1013 function run(;initialize=true)
1014 # Begin with STDIN as source
1015 push!(sources, STDIN)
1017 global initialized, initFileName
1018 if !initialized && initialize
1019 if initFileName != nothing
1020 print("Including definitions from $initFileName...")
1021 push!(sources, open(initFileName, "r"))
1024 println("No library file found. Only primitive words available.")
1028 # Start with IP pointing to first instruction of outer interpreter
1031 # Primitive processing loop.
1032 # Everyting else is simply a consequence of this loop!
1036 #println("Entering prim $(getPrimName(jmp))")
1040 showerror(STDOUT, ex)
1043 while !isempty(sources) && currentSource() != STDIN
1044 close(pop!(sources))
1056 function dump(startAddr::Int64; count::Int64 = 100, cellsPerLine::Int64 = 10)
1057 chars = Array{Char,1}(cellsPerLine)
1059 lineStartAddr = cellsPerLine*div((startAddr-1),cellsPerLine) + 1
1060 endAddr = startAddr + count - 1
1062 q, r = divrem((endAddr-lineStartAddr+1), cellsPerLine)
1063 numLines = q + (r > 0 ? 1 : 0)
1069 for c in 1:cellsPerLine
1070 if i >= startAddr && i <= endAddr
1072 if mem[i]>=32 && mem[i]<128
1073 chars[c] = Char(mem[i])
1085 println("\t", ASCIIString(chars))
1090 count = reg.PSP - PSP0
1094 for i in (PSP0+1):reg.PSP
1099 println("Parameter stack empty")
1104 count = reg.RSP - RSP0
1108 for i in (RSP0+1):reg.RSP
1113 println("Return stack empty")
1117 DUMP = defPrimWord("DUMP", () -> begin
1121 dump(addr, count=count)