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
138 function createHeader(name::AbstractString, flags::Int64)
139 mem[mem[H]] = mem[LATEST]
143 mem[mem[H]] = length(name) | flags; mem[H] += 1
144 putString(name, mem[H]); mem[H] += length(name)
147 function defPrimWord(name::AbstractString, f::Function; flags::Int64=0)
148 createHeader(name, flags)
150 codeWordAddr = mem[H]
151 mem[codeWordAddr] = defPrim(f, name=name)
157 function defWord(name::AbstractString, wordAddrs::Array{Int64,1}; flags::Int64=0)
158 createHeader(name, flags)
164 for wordAddr in wordAddrs
165 mem[mem[H]] = wordAddr
172 # Variable creation functions
174 function defExistingVar(name::AbstractString, varAddr::Int64; flags::Int64=0)
176 defPrimWord(name, eval(:(() -> begin
182 function defNewVar(name::AbstractString, initial::Int64; flags::Int64=0)
183 createHeader(name, flags)
185 codeWordAddr = mem[H]
188 mem[mem[H]] = DOVAR; mem[H] += 1
189 mem[mem[H]] = initial; mem[H] += 1
191 return varAddr, codeWordAddr
194 function defConst(name::AbstractString, val::Int64; flags::Int64=0)
195 createHeader(name, flags)
197 codeWordAddr = mem[H]
199 mem[mem[H]] = DOCON; mem[H] += 1
200 mem[mem[H]] = val; mem[H] += 1
205 # Threading Primitives (inner interpreter)
207 NEXT = defPrim(() -> begin
213 DOCOL = defPrim(() -> begin
219 DOVAR = defPrim(() -> begin
224 DOCON = defPrim(() -> begin
225 pushPS(mem[reg.W + 1])
229 EXIT = defPrimWord("EXIT", () -> begin
234 # Dictionary entries for core built-in variables, constants
236 H_CFA = defExistingVar("H", H)
237 LATEST_CFA = defExistingVar("LATEST", LATEST)
239 PSP0_CFA = defConst("PSP0", PSP0)
240 RSP0_CFA = defConst("RSP0", RSP0)
242 defConst("DOCOL", DOCOL)
243 defConst("DOCON", DOCON)
244 defConst("DOVAR", DOVAR)
246 defConst("DICT", DICT)
247 defConst("MEMSIZE", size_mem)
249 F_IMMED_CFA = defConst("F_IMMED", F_IMMED)
250 F_HIDDEN_CFA = defConst("F_HIDDEN", F_HIDDEN)
251 F_LENMASK_CFA = defConst("F_LENMASK", F_LENMASK)
253 # Basic forth primitives
255 DROP = defPrimWord("DROP", () -> begin
260 SWAP = defPrimWord("SWAP", () -> begin
268 DUP = defPrimWord("DUP", () -> begin
274 OVER = defPrimWord("OVER", () -> begin
276 pushPS(mem[reg.PSP-1])
280 ROT = defPrimWord("ROT", () -> begin
290 NROT = defPrimWord("-ROT", () -> begin
301 TWODROP = defPrimWord("2DROP", () -> begin
307 TWODUP = defPrimWord("2DUP", () -> begin
316 TWOSWAP = defPrimWord("2SWAP", () -> begin
328 TWOOVER = defPrimWord("2OVER", () -> begin
337 QDUP = defPrimWord("?DUP", () -> begin
346 INCR = defPrimWord("1+", () -> begin
352 DECR = defPrimWord("1-", () -> begin
358 INCR2 = defPrimWord("2+", () -> begin
364 DECR2 = defPrimWord("2-", () -> begin
370 ADD = defPrimWord("+", () -> begin
377 SUB = defPrimWord("-", () -> begin
384 MUL = defPrimWord("*", () -> begin
391 DIVMOD = defPrimWord("/MOD", () -> begin
400 TWOMUL = defPrimWord("2*", () -> begin
405 TWODIV = defPrimWord("2/", () -> begin
410 EQ = defPrimWord("=", () -> begin
413 pushPS(a==b ? -1 : 0)
417 NE = defPrimWord("<>", () -> begin
420 pushPS(a!=b ? -1 : 0)
424 LT = defPrimWord("<", () -> begin
431 GT = defPrimWord(">", () -> begin
438 LE = defPrimWord("<=", () -> begin
441 pushPS(a<=b ? -1 : 0)
445 GE = defPrimWord(">=", () -> begin
448 pushPS(a>=b ? -1 : 0)
452 ZE = defPrimWord("0=", () -> begin
453 pushPS(popPS() == 0 ? -1 : 0)
457 ZNE = defPrimWord("0<>", () -> begin
458 pushPS(popPS() != 0 ? -1 : 0)
462 ZLT = defPrimWord("0<", () -> begin
463 pushPS(popPS() < 0 ? -1 : 0)
467 ZGT = defPrimWord("0>", () -> begin
468 pushPS(popPS() > 0 ? -1 : 0)
472 ZLE = defPrimWord("0<=", () -> begin
473 pushPS(popPS() <= 0 ? -1 : 0)
477 ZGE = defPrimWord("0>=", () -> begin
478 pushPS(popPS() >= 0 ? -1 : 0)
482 AND = defPrimWord("AND", () -> begin
489 OR = defPrimWord("OR", () -> begin
496 XOR = defPrimWord("XOR", () -> begin
503 INVERT = defPrimWord("INVERT", () -> begin
510 LIT = defPrimWord("LIT", () -> begin
518 STORE = defPrimWord("!", () -> begin
525 FETCH = defPrimWord("@", () -> begin
531 ADDSTORE = defPrimWord("+!", () -> begin
538 SUBSTORE = defPrimWord("-!", () -> begin
548 TOR = defPrimWord(">R", () -> begin
553 FROMR = defPrimWord("R>", () -> begin
558 RFETCH = defPrimWord("R@", () -> begin
563 RSPFETCH = defPrimWord("RSP@", () -> begin
568 RSPSTORE = defPrimWord("RSP!", () -> begin
573 RDROP = defPrimWord("RDROP", () -> begin
580 PSPFETCH = defPrimWord("PSP@", () -> begin
585 PSPSTORE = defPrimWord("PSP!", () -> begin
592 WFETCH = defPrimWord("W@", () -> begin
597 WSTORE = defPrimWord("W!", () -> begin
604 sources = Array{Any,1}()
605 currentSource() = sources[length(sources)]
607 EOF = defPrimWord("\x04", () -> begin
616 EMIT = defPrimWord("EMIT", () -> begin
621 SPAN, SPAN_CFA = defNewVar("SPAN", 0)
622 EXPECT = defPrimWord("EXPECT", () -> begin
626 if !eof(currentSource())
627 line = chomp(readline(currentSource()))
628 mem[SPAN] = min(length(line), maxLen)
629 putString(line[1:mem[SPAN]], addr)
638 BASE, BASE_CFA = defNewVar("BASE", 10)
639 NUMBER = defPrimWord("NUMBER", () -> begin
641 wordLen = mem[wordAddr-1]
643 s = getString(wordAddr, wordLen)
645 pushPS(parse(Int64, s, mem[BASE]))
650 # Dictionary searches
652 FIND = defPrimWord("FIND", () -> begin
654 countedAddr = popPS()
655 wordAddr = countedAddr + 1
656 wordLen = mem[countedAddr]
657 word = lowercase(getString(wordAddr, wordLen))
662 while (latest = mem[latest]) > 0
663 lenAndFlags = mem[latest+1]
664 len = lenAndFlags & F_LENMASK
665 hidden = (lenAndFlags & F_HIDDEN) == F_HIDDEN
667 if hidden || len != wordLen
672 thisWord = lowercase(getString(thisAddr, len))
674 if lowercase(thisWord) == lowercase(word)
684 TOCFA = defPrimWord(">CFA", () -> begin
687 lenAndFlags = mem[addr+1]
688 len = lenAndFlags & F_LENMASK
690 pushPS(addr + 2 + len)
695 TOPFA = defWord(">PFA", [TOCFA, INCR, EXIT])
699 BRANCH = defPrimWord("BRANCH", () -> begin
700 reg.IP += mem[reg.IP]
704 ZBRANCH = defPrimWord("0BRANCH", () -> begin
706 reg.IP += mem[reg.IP]
716 LITSTRING = defPrimWord("LITSTRING", () -> begin
726 TYPE = defPrimWord("TYPE", () -> begin
729 str = getString(addr, len)
736 TRACE = defPrimWord("TRACE", () -> begin
737 println("reg.W: $(reg.W) reg.IP: $(reg.IP)")
738 print("PS: "); printPS()
739 print("RS: "); printRS()
746 COMMA = defPrimWord(",", () -> begin
747 mem[mem[H]] = popPS()
753 BTICK = defWord("[']",
754 [FROMR, DUP, INCR, TOR, FETCH, EXIT])
756 EXECUTE = defPrimWord("EXECUTE", () -> begin
761 TIB_CFA = defConst("TIB", TIB)
762 NUMTIB, NUMTIB_CFA = defNewVar("#TIB", 0)
763 TOIN, TOIN_CFA = defNewVar(">IN", 0)
765 QUERY = defWord("QUERY",
766 [TIB_CFA, LIT, 160, EXPECT,
767 SPAN_CFA, FETCH, NUMTIB_CFA, STORE,
768 LIT, 0, TOIN_CFA, STORE,
771 WORD = defPrimWord("WORD", () -> begin
774 # Chew up initial occurrences of delim
775 while (mem[TOIN]<mem[NUMTIB] && mem[TIB+mem[TOIN]] == delim)
782 # Start reading in word
784 while (mem[TOIN]<mem[NUMTIB])
785 mem[addr] = mem[TIB+mem[TOIN]]
788 if (mem[addr] == delim)
797 mem[countAddr] = count
803 PARSE = defPrimWord("PARSE", () -> begin
806 # Chew up initial occurrences of delim
809 # Start reading input stream
811 while (mem[TOIN]<mem[NUMTIB])
812 mem[addr] = mem[TIB+mem[TOIN]]
815 if (mem[addr] == delim)
829 BYE = defPrimWord("BYE", () -> begin
834 STATE, STATE_CFA = defNewVar("STATE", 0)
836 INTERPRET = defWord("INTERPRET",
837 [LIT, 32, WORD, # Read next space-delimited word
839 DUP, FETCH, ZE, ZBRANCH, 3,
840 DROP, EXIT, # Exit if TIB is exhausted
842 STATE_CFA, FETCH, ZBRANCH, 31,
844 DUP, FIND, QDUP, ZBRANCH, 19,
848 DUP, TOCFA, SWAP, INCR, FETCH, LIT, F_IMMED, AND, ZBRANCH, 4,
849 # Immediate: Execute!
850 EXECUTE, BRANCH, -33,
852 # Not immediate: Compile!
855 # No word found, parse number
856 NUMBER, BTICK, LIT, COMMA, COMMA, BRANCH, -43,
859 DUP, FIND, QDUP, ZBRANCH, 7,
861 # Found word. Execute!
862 SWAP, DROP, TOCFA, EXECUTE, BRANCH, -54,
864 # No word found, parse number and leave on stack
869 PROMPT = defPrimWord("PROMPT", () -> begin
870 if (mem[STATE] == 0 && currentSource() == STDIN)
877 QUIT = defWord("QUIT",
878 [LIT, 0, STATE_CFA, STORE,
879 LIT, 0, NUMTIB_CFA, STORE,
885 ABORT = defWord("ABORT",
886 [PSP0_CFA, PSPSTORE, QUIT])
888 INCLUDE = defPrimWord("INCLUDE", () -> begin
892 wordLen = mem[wordAddr-1]
893 word = getString(wordAddr, wordLen)
895 push!(sources, open(word, "r"))
905 HEADER = defPrimWord("HEADER", () -> begin
907 wordLen = mem[wordAddr-1]
908 word = getString(wordAddr, wordLen)
910 createHeader(word, 0)
915 CREATE = defWord("CREATE",
916 [LIT, 32, WORD, HEADER,
920 DODOES = defPrim(() -> begin
926 BDOES = defPrimWord("(DOES>)", () -> begin
932 mem[cfa] = defPrim(eval(:(() -> begin
935 end)), name="doesPrim")
937 mem[mem[H]] = LIT; mem[H] += 1
938 mem[mem[H]] = cfa+1; mem[H] += 1
943 DOES = defWord("DOES>",
946 LBRAC = defPrimWord("[", () -> begin
951 RBRAC = defPrimWord("]", () -> begin
956 HIDDEN = defPrimWord("HIDDEN", () -> begin
958 mem[addr] = mem[addr] $ F_HIDDEN
962 HIDE = defWord("HIDE",
972 LATEST_CFA, FETCH, HIDDEN,
976 SEMICOLON = defWord(";",
978 LATEST_CFA, FETCH, HIDDEN,
980 EXIT], flags=F_IMMED)
982 IMMEDIATE = defPrimWord("IMMEDIATE", () -> begin
983 lenAndFlagsAddr = mem[LATEST] + 1
984 mem[lenAndFlagsAddr] = mem[lenAndFlagsAddr] $ F_IMMED
992 initFileName = nothing
994 initFileName = "lib.4th"
995 elseif isfile(Pkg.dir("forth/src/lib.4th"))
996 initFileName = Pkg.dir("forth/src/lib.4th")
999 function run(;initialize=true)
1000 # Begin with STDIN as source
1001 push!(sources, STDIN)
1003 global initialized, initFileName
1004 if !initialized && initialize
1005 if initFileName != nothing
1006 print("Including definitions from $initFileName...")
1007 push!(sources, open(initFileName, "r"))
1010 println("No library file found. Only primitive words available.")
1014 # Start with IP pointing to first instruction of outer interpreter
1017 # Primitive processing loop.
1018 # Everyting else is simply a consequence of this loop!
1022 #println("Entering prim $(getPrimName(jmp))")
1026 showerror(STDOUT, ex)
1029 while !isempty(sources) && currentSource() != STDIN
1030 close(pop!(sources))
1042 function dump(startAddr::Int64; count::Int64 = 100, cellsPerLine::Int64 = 10)
1043 chars = Array{Char,1}(cellsPerLine)
1045 lineStartAddr = cellsPerLine*div((startAddr-1),cellsPerLine) + 1
1046 endAddr = startAddr + count - 1
1048 q, r = divrem((endAddr-lineStartAddr+1), cellsPerLine)
1049 numLines = q + (r > 0 ? 1 : 0)
1055 for c in 1:cellsPerLine
1056 if i >= startAddr && i <= endAddr
1058 if mem[i]>=32 && mem[i]<128
1059 chars[c] = Char(mem[i])
1071 println("\t", ASCIIString(chars))
1076 count = reg.PSP - PSP0
1080 for i in (PSP0+1):reg.PSP
1085 println("Parameter stack empty")
1090 count = reg.RSP - RSP0
1094 for i in (RSP0+1):reg.RSP
1099 println("Return stack empty")
1103 DUMP = defPrimWord("DUMP", () -> begin
1107 dump(addr, count=count)