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 the negative index
30 # into the primitives array which contains only 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 reg = Reg(mem[RSP0], mem[PSP0], 0, 0)
63 type StackUnderflow <: Exception end
65 getRSDepth() = reg.RSP - mem[RSP0]
66 getPSDepth() = reg.PSP - mem[PSP0]
68 function ensurePSDepth(depth::Int64)
70 throw(StackUnderflow())
74 function ensureRSDepth(depth::Int64)
76 throw(StackUnderflow())
80 function pushRS(val::Int64)
92 function pushPS(val::Int64)
93 mem[reg.PSP += 1] = val
104 # Handy functions for adding/retrieving strings to/from memory.
106 getString(addr::Int64, len::Int64) = ASCIIString([Char(c) for c in mem[addr:(addr+len-1)]])
107 function putString(str::ASCIIString, addr::Int64)
108 mem[addr:(addr+length(str)-1)] = [Int64(c) for c in str]
111 # Primitive creation and calling functions
113 function defPrim(f::Function; name="nameless")
115 push!(primNames, name)
117 return -length(primitives)
120 callPrim(addr::Int64) = primitives[-addr]()
124 function createHeader(name::AbstractString, flags::Int64)
125 mem[mem[HERE]] = mem[LATEST]
126 mem[LATEST] = mem[HERE]
129 mem[mem[HERE]] = length(name) | flags; mem[HERE] += 1
130 putString(name, mem[HERE]); mem[HERE] += length(name)
133 function defPrimWord(name::AbstractString, f::Function; flags::Int64=0)
134 createHeader(name, flags)
136 codeWordAddr = mem[HERE]
137 mem[codeWordAddr] = defPrim(f, name=name)
143 function defWord(name::AbstractString, wordAddrs::Array{Int64,1}; flags::Int64=0)
144 createHeader(name, flags)
147 mem[mem[HERE]] = DOCOL
150 for wordAddr in wordAddrs
151 mem[mem[HERE]] = wordAddr
160 function defExistingVar(name::AbstractString, varAddr::Int64; flags::Int64=0)
162 defPrimWord(name, eval(:(() -> begin
168 function defNewVar(name::AbstractString, initial::Int64; flags::Int64=0)
169 createHeader(name, flags)
171 codeWordAddr = mem[HERE]
172 varAddr = mem[HERE] + 1
174 f = eval(:(() -> begin
179 mem[mem[HERE]] = defPrim(f, name=name); mem[HERE] += 1
180 mem[mem[HERE]] = initial; mem[HERE] += 1
182 return varAddr, codeWordAddr
185 function defConst(name::AbstractString, val::Int64; flags::Int64=0)
186 defPrimWord(name, eval(:(() -> begin
194 # Threading Primitives (inner interpreter)
196 NEXT = defPrim(() -> begin
202 DOCOL = defPrim(() -> begin
208 EXIT = defPrimWord("EXIT", () -> begin
213 # Basic forth primitives
215 DROP = defPrimWord("DROP", () -> begin
220 SWAP = defPrimWord("SWAP", () -> begin
228 DUP = defPrimWord("DUP", () -> begin
233 OVER = defPrimWord("OVER", () -> begin
235 pushPS(mem[reg.PSP-1])
239 ROT = defPrimWord("ROT", () -> begin
249 NROT = defPrimWord("-ROT", () -> begin
259 TWODROP = defPrimWord("2DROP", () -> begin
265 TWODUP = defPrimWord("2DUP", () -> begin
274 TWOSWAP = defPrimWord("2SWAP", () -> begin
286 QDUP = defPrimWord("?DUP", () -> begin
295 INCR = defPrimWord("1+", () -> begin
301 DECR = defPrimWord("1-", () -> begin
307 INCR2 = defPrimWord("2+", () -> begin
313 DECR2 = defPrimWord("2-", () -> begin
319 ADD = defPrimWord("+", () -> begin
326 SUB = defPrimWord("-", () -> begin
333 MUL = defPrimWord("*", () -> begin
340 DIVMOD = defPrimWord("/MOD", () -> begin
349 EQU = defPrimWord("=", () -> begin
352 pushPS(a==b ? -1 : 0)
356 NEQU = defPrimWord("<>", () -> begin
359 pushPS(a!=b ? -1 : 0)
363 LT = defPrimWord("<", () -> begin
370 GT = defPrimWord(">", () -> begin
377 LE = defPrimWord("<=", () -> begin
380 pushPS(a<=b ? -1 : 0)
384 GE = defPrimWord(">=", () -> begin
387 pushPS(a>=b ? -1 : 0)
391 ZEQU = defPrimWord("0=", () -> begin
392 pushPS(popPS() == 0 ? -1 : 0)
396 ZNEQU = defPrimWord("0<>", () -> begin
397 pushPS(popPS() != 0 ? -1 : 0)
401 ZLT = defPrimWord("0<", () -> begin
402 pushPS(popPS() < 0 ? -1 : 0)
406 ZGT = defPrimWord("0>", () -> begin
407 pushPS(popPS() > 0 ? -1 : 0)
411 ZLE = defPrimWord("0<=", () -> begin
412 pushPS(popPS() <= 0 ? -1 : 0)
416 ZGE = defPrimWord("0>=", () -> begin
417 pushPS(popPS() >= 0 ? -1 : 0)
421 AND = defPrimWord("AND", () -> begin
428 OR = defPrimWord("OR", () -> begin
435 XOR = defPrimWord("XOR", () -> begin
442 INVERT = defPrimWord("INVERT", () -> begin
449 LIT = defPrimWord("LIT", () -> begin
457 STORE = defPrimWord("!", () -> begin
464 FETCH = defPrimWord("@", () -> begin
470 ADDSTORE = defPrimWord("+!", () -> begin
477 SUBSTORE = defPrimWord("-!", () -> begin
487 HERE_CFA = defExistingVar("HERE", HERE)
488 LATEST_CFA = defExistingVar("LATEST", LATEST)
489 PSP0_CFA = defExistingVar("PSP0", PSP0)
490 RSP0_CFA = defExistingVar("RSP0", RSP0)
491 STATE, STATE_CFA = defNewVar("STATE", 0)
492 BASE, BASE_CFA = defNewVar("BASE", 10)
496 defConst("VERSION", 1)
497 defConst("DOCOL", DOCOL)
498 defConst("DICT", DICT)
499 F_IMMED = defConst("F_IMMED", 128)
500 F_HIDDEN = defConst("F_HIDDEN", 256)
501 F_LENMASK = defConst("F_LENMASK", 127)
505 TOR = defPrimWord(">R", () -> begin
510 FROMR = defPrimWord("R>", () -> begin
515 RSPFETCH = defPrimWord("RSP@", () -> begin
520 RSPSTORE = defPrimWord("RSP!", () -> begin
525 RDROP = defPrimWord("RDROP", () -> begin
532 PSPFETCH = defPrimWord("PSP@", () -> begin
537 PSPSTORE = defPrimWord("PSP!", () -> begin
544 WFETCH = defPrimWord("W@", () -> begin
549 WSTORE = defPrimWord("W!", () -> begin
557 NUMTIB, NUMTIB_CFA = defNewVar("#TIB", 0)
558 TOIN, TOIN_CFA = defNewVar(">IN", 0)
560 KEY = defPrimWord("KEY", () -> begin
561 if mem[TOIN] >= mem[NUMTIB]
564 mem[NUMTIB] = length(line)
568 pushPS(mem[TIB + mem[TOIN]])
574 EMIT = defPrimWord("EMIT", () -> begin
579 WORD = defPrimWord("WORD", () -> begin
601 if c == ' ' || c == '\t'
612 # Treat newline as a special word
614 mem[wordAddr + offset] = Int64(c)
621 mem[wordAddr + offset] = Int64(c)
627 if c == ' ' || c == '\t' || c == '\n'
642 NUMBER = defPrimWord("NUMBER", () -> begin
647 s = getString(wordAddr, wordLen)
650 pushPS(parse(Int64, s, mem[BASE]))
653 pushPS(1) # Error indication
659 # Dictionary searches
661 FIND = defPrimWord("FIND", () -> begin
665 word = lowercase(getString(wordAddr, wordLen))
670 while (latest = mem[latest]) > 0
671 lenAndFlags = mem[latest+1]
672 len = lenAndFlags & F_LENMASK
673 hidden = (lenAndFlags & F_HIDDEN) == F_HIDDEN
675 if hidden || len != wordLen
680 thisWord = lowercase(getString(thisAddr, len))
682 if lowercase(thisWord) == lowercase(word)
692 TOCFA = defPrimWord(">CFA", () -> begin
695 lenAndFlags = mem[addr+1]
696 len = lenAndFlags & F_LENMASK
698 pushPS(addr + 2 + len)
703 TODFA = defWord(">DFA", [TOCFA, INCR, EXIT])
707 CREATE = defPrimWord("CREATE", () -> begin
711 word = getString(wordAddr, wordLen)
713 createHeader(word, 0)
718 COMMA = defPrimWord(",", () -> begin
719 mem[mem[HERE]] = popPS()
725 LBRAC = defPrimWord("[", () -> begin
730 RBRAC = defPrimWord("]", () -> begin
735 HIDDEN = defPrimWord("HIDDEN", () -> begin
737 mem[addr] = mem[addr] $ F_HIDDEN
741 HIDE = defWord("HIDE",
751 LATEST_CFA, FETCH, HIDDEN,
755 SEMICOLON = defWord(";",
757 LATEST_CFA, FETCH, HIDDEN,
759 EXIT], flags=F_IMMED)
761 IMMEDIATE = defPrimWord("IMMEDIATE", () -> begin
762 lenAndFlagsAddr = mem[LATEST] + 1
763 mem[lenAndFlagsAddr] = mem[lenAndFlagsAddr] $ F_IMMED
767 TICK = defWord("'", [WORD, FIND, TOCFA, EXIT])
771 BRANCH = defPrimWord("BRANCH", () -> begin
772 reg.IP += mem[reg.IP]
776 ZBRANCH = defPrimWord("0BRANCH", () -> begin
778 reg.IP += mem[reg.IP]
788 LITSTRING = defPrimWord("LITSTRING", () -> begin
798 TELL = defPrimWord("TELL", () -> begin
801 str = getString(addr, len)
808 EXECUTE = defPrimWord("EXECUTE", () -> begin
813 INTERPRET = defPrimWord("INTERPRET", () -> begin
817 wordName = getString(mem[reg.PSP-1], mem[reg.PSP])
818 #println("... ", replace(wordName, "\n", "\\n"), " ...")
820 callPrim(mem[TWODUP])
823 wordAddr = mem[reg.PSP]
828 isImmediate = (mem[wordAddr+1] & F_IMMED) != 0
831 callPrim(mem[ROT]) # get rid of extra copy of word string details
835 if mem[STATE] == 0 || isImmediate
837 #println("Executing CFA at $(mem[reg.PSP])")
838 return callPrim(mem[EXECUTE])
840 # Append CFA to dictionary
844 # Not in dictionary, assume number
848 callPrim(mem[NUMBER])
851 println("Parse error at word: '$wordName'")
856 # Number already on stack!
858 # Append literal to dictionary
868 QUIT = defWord("QUIT",
873 NL = defPrimWord("\n", () -> begin
882 CHAR = defPrimWord("CHAR", () -> begin
886 word = getString(wordAddr, wordLen)
887 pushPS(Int64(word[1]))
892 BYE = defPrimWord("BYE", () -> begin
898 # Start with IP pointing to first instruction of outer interpreter
901 # Primitive processing loop.
902 # Everyting else is simply a consequence of this loop!
904 while (jmp = callPrim(jmp)) != 0
905 #println("Evaluating prim $jmp [$(primNames[-jmp])]")
911 function dump(startAddr::Int64; count::Int64 = 100, cellsPerLine::Int64 = 10)
912 chars = Array{Char,1}(cellsPerLine)
914 lineStartAddr = cellsPerLine*div((startAddr-1),cellsPerLine) + 1
915 endAddr = startAddr + count - 1
917 q, r = divrem((endAddr-lineStartAddr+1), cellsPerLine)
918 numLines = q + (r > 0 ? 1 : 0)
924 for c in 1:cellsPerLine
925 if i >= startAddr && i <= endAddr
927 if mem[i]>=32 && mem[i]<128
928 chars[c] = Char(mem[i])
940 println("\t", ASCIIString(chars))
945 count = reg.PSP - mem[PSP0]
949 for i in (mem[PSP0]+1):reg.PSP
954 println("Parameter stack empty")
959 count = reg.RSP - mem[RSP0]
963 for i in (mem[RSP0]+1):reg.RSP
968 println("Return stack empty")