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
58 X::Int64 # Extra register
60 reg = Reg(mem[RSP0], mem[PSP0], 0, 0, 0)
64 type StackUnderflow <: Exception end
66 getRSDepth() = reg.RSP - mem[RSP0]
67 getPSDepth() = reg.PSP - mem[PSP0]
69 function ensurePSDepth(depth::Int64)
71 throw(StackUnderflow())
75 function ensureRSDepth(depth::Int64)
77 throw(StackUnderflow())
81 function pushRS(val::Int64)
93 function pushPS(val::Int64)
94 mem[reg.PSP += 1] = val
105 # Handy functions for adding/retrieving strings to/from memory.
107 getString(addr::Int64, len::Int64) = ASCIIString([Char(c) for c in mem[addr:(addr+len-1)]])
108 function putString(str::ASCIIString, addr::Int64)
109 mem[addr:(addr+length(str)-1)] = [Int64(c) for c in str]
112 # Primitive creation and calling functions
114 function createHeader(name::AbstractString, flags::Int64)
115 mem[mem[HERE]] = mem[LATEST]
116 mem[LATEST] = mem[HERE]
119 mem[mem[HERE]] = length(name) | flags; mem[HERE] += 1
120 putString(name, mem[HERE]); mem[HERE] += length(name)
123 function defPrim(name::AbstractString, f::Function; flags::Int64=0)
124 createHeader(name, flags)
126 codeWordAddr = mem[HERE]
128 mem[codeWordAddr] = -length(primitives)
131 push!(primNames, name)
136 callPrim(addr::Int64) = primitives[-addr]()
138 function defExistingVar(name::AbstractString, varAddr::Int64; flags::Int64=0)
139 defPrim(name, eval(:(() -> begin
145 function defNewVar(name::AbstractString, initial::Int64; flags::Int64=0)
146 createHeader(name, flags)
148 codeWordAddr = mem[HERE]
149 varAddr = mem[HERE] + 1
150 push!(primitives, eval(:(() -> begin
154 mem[mem[HERE]] = -length(primitives); mem[HERE] += 1
156 mem[mem[HERE]] = initial; mem[HERE] += 1
158 return varAddr, codeWordAddr
161 function defConst(name::AbstractString, val::Int64; flags::Int64=0)
162 defPrim(name, eval(:(() -> begin
170 function defWord(name::AbstractString, wordAddrs::Array{Int64,1}; flags::Int64=0)
171 createHeader(name, flags)
174 mem[mem[HERE]] = mem[DOCOL]
177 for wordAddr in wordAddrs
178 mem[mem[HERE]] = wordAddr
185 # Threading Primitives (inner interpreter)
187 NEXT = defPrim("NEXT", () -> begin
193 DOCOL = defPrim("DOCOL", () -> begin
199 EXIT = defPrim("EXIT", () -> begin
204 # Basic forth primitives
206 DROP = defPrim("DROP", () -> begin
211 SWAP = defPrim("SWAP", () -> begin
219 DUP = defPrim("DUP", () -> begin
224 OVER = defPrim("OVER", () -> begin
226 pushPS(mem[reg.PSP-1])
230 ROT = defPrim("ROT", () -> begin
240 NROT = defPrim("-ROT", () -> begin
250 TWODROP = defPrim("2DROP", () -> begin
256 TWODUP = defPrim("2DUP", () -> begin
265 TWOSWAP = defPrim("2SWAP", () -> begin
277 QDUP = defPrim("?DUP", () -> begin
286 INCR = defPrim("1+", () -> begin
292 DECR = defPrim("1-", () -> begin
298 INCR2 = defPrim("2+", () -> begin
304 DECR2 = defPrim("2-", () -> begin
310 ADD = defPrim("+", () -> begin
317 SUB = defPrim("-", () -> begin
324 MUL = defPrim("*", () -> begin
331 DIVMOD = defPrim("/MOD", () -> begin
340 EQU = defPrim("=", () -> begin
343 pushPS(a==b ? -1 : 0)
347 NEQU = defPrim("<>", () -> begin
350 pushPS(a!=b ? -1 : 0)
354 LT = defPrim("<", () -> begin
361 GT = defPrim(">", () -> begin
368 LE = defPrim("<=", () -> begin
371 pushPS(a<=b ? -1 : 0)
375 GE = defPrim(">=", () -> begin
378 pushPS(a>=b ? -1 : 0)
382 ZEQU = defPrim("0=", () -> begin
383 pushPS(popPS() == 0 ? -1 : 0)
387 ZNEQU = defPrim("0<>", () -> begin
388 pushPS(popPS() != 0 ? -1 : 0)
392 ZLT = defPrim("0<", () -> begin
393 pushPS(popPS() < 0 ? -1 : 0)
397 ZGT = defPrim("0>", () -> begin
398 pushPS(popPS() > 0 ? -1 : 0)
402 ZLE = defPrim("0<=", () -> begin
403 pushPS(popPS() <= 0 ? -1 : 0)
407 ZGE = defPrim("0>=", () -> begin
408 pushPS(popPS() >= 0 ? -1 : 0)
412 AND = defPrim("AND", () -> begin
419 OR = defPrim("OR", () -> begin
426 XOR = defPrim("XOR", () -> begin
433 INVERT = defPrim("INVERT", () -> begin
440 LIT = defPrim("LIT", () -> begin
448 STORE = defPrim("!", () -> begin
455 FETCH = defPrim("@", () -> begin
461 ADDSTORE = defPrim("+!", () -> begin
468 SUBSTORE = defPrim("-!", () -> begin
478 HERE_CFA = defExistingVar("HERE", HERE)
479 LATEST_CFA = defExistingVar("LATEST", LATEST)
480 PSP0_CFA = defExistingVar("PSP0", PSP0)
481 RSP0_CFA = defExistingVar("RSP0", RSP0)
482 STATE, STATE_CFA = defNewVar("STATE", 0)
483 BASE, BASE_CFA = defNewVar("BASE", 10)
487 defConst("VERSION", 1)
488 defConst("DOCOL", DOCOL)
489 defConst("DICT", DICT)
490 F_IMMED = defConst("F_IMMED", 128)
491 F_HIDDEN = defConst("F_HIDDEN", 256)
492 F_LENMASK = defConst("F_LENMASK", 127)
496 TOR = defPrim(">R", () -> begin
501 FROMR = defPrim("R>", () -> begin
506 RSPFETCH = defPrim("RSP@", () -> begin
511 RSPSTORE = defPrim("RSP!", () -> begin
516 RDROP = defPrim("RDROP", () -> begin
523 PSPFETCH = defPrim("PSP@", () -> begin
528 PSPSTORE = defPrim("PSP!", () -> begin
536 NUMTIB, NUMTIB_CFA = defNewVar("#TIB", 0)
537 TOIN, TOIN_CFA = defNewVar(">IN", 0)
539 KEY = defPrim("KEY", () -> begin
540 if mem[TOIN] >= mem[NUMTIB]
543 mem[NUMTIB] = length(line)
547 pushPS(mem[TIB + mem[TOIN]])
553 EMIT = defPrim("EMIT", () -> begin
558 WORD = defPrim("WORD", () -> begin
580 if c == ' ' || c == '\t'
591 # Treat newline as a special word
593 mem[wordAddr + offset] = Int64(c)
600 mem[wordAddr + offset] = Int64(c)
606 if c == ' ' || c == '\t' || c == '\n'
621 NUMBER = defPrim("NUMBER", () -> begin
626 s = getString(wordAddr, wordLen)
629 pushPS(parse(Int64, s, mem[BASE]))
632 pushPS(1) # Error indication
638 # Dictionary searches
640 FIND = defPrim("FIND", () -> begin
644 word = lowercase(getString(wordAddr, wordLen))
649 while (latest = mem[latest]) > 0
650 lenAndFlags = mem[latest+1]
651 len = lenAndFlags & F_LENMASK
652 hidden = (lenAndFlags & F_HIDDEN) == F_HIDDEN
654 if hidden || len != wordLen
659 thisWord = lowercase(getString(thisAddr, len))
661 if lowercase(thisWord) == lowercase(word)
671 TOCFA = defPrim(">CFA", () -> begin
674 lenAndFlags = mem[addr+1]
675 len = lenAndFlags & F_LENMASK
677 pushPS(addr + 2 + len)
682 TODFA = defWord(">DFA", [TOCFA, INCR, EXIT])
686 CREATE = defPrim("CREATE", () -> begin
690 word = getString(wordAddr, wordLen)
692 createHeader(word, 0)
697 COMMA = defPrim(",", () -> begin
698 mem[mem[HERE]] = popPS()
704 LBRAC = defPrim("[", () -> begin
709 RBRAC = defPrim("]", () -> begin
714 HIDDEN = defPrim("HIDDEN", () -> begin
716 mem[addr] = mem[addr] $ F_HIDDEN
720 HIDE = defWord("HIDE",
730 LATEST, FETCH, HIDDEN,
734 SEMICOLON = defWord(";",
736 LATEST, FETCH, HIDDEN,
738 EXIT], flags=F_IMMED)
740 IMMEDIATE = defPrim("IMMEDIATE", () -> begin
741 lenAndFlagsAddr = mem[LATEST] + 1
742 mem[lenAndFlagsAddr] = mem[lenAndFlagsAddr] $ F_IMMED
746 TICK = defWord("'", [WORD, FIND, TOCFA, EXIT])
750 BRANCH = defPrim("BRANCH", () -> begin
751 reg.IP += mem[reg.IP]
755 ZBRANCH = defPrim("0BRANCH", () -> begin
757 reg.IP += mem[reg.IP]
767 LITSTRING = defPrim("LITSTRING", () -> begin
777 TELL = defPrim("TELL", () -> begin
780 str = getString(addr, len)
787 INTERPRET = defPrim("INTERPRET", () -> begin
791 wordName = getString(mem[reg.PSP-1], mem[reg.PSP])
792 println("... ", replace(wordName, "\n", "\\n"), " ...")
794 callPrim(mem[TWODUP])
797 wordAddr = mem[reg.PSP]
803 isImmediate = (mem[wordAddr+1] & F_IMMED) != 0
806 callPrim(mem[ROT]) # get rid of extra copy of word string details
810 if mem[STATE] == 0 || isImmediate
814 # Append CFA to dictionary
818 # Not in dictionary, assume number
822 callPrim(mem[NUMBER])
825 println("Parse error at word: '$wordName'")
831 # Number already on stack!
833 # Append literal to dictionary
843 QUIT = defWord("QUIT",
848 NL = defPrim("\n", () -> begin
857 CHAR = defPrim("CHAR", () -> begin
861 word = getString(wordAddr, wordLen)
862 pushPS(Int64(word[1]))
867 EXECUTE = defPrim("EXECUTE", () -> begin
871 BYE = defPrim("BYE", () -> begin
877 # Start with IP pointing to first instruction of outer interpreter
880 # Primitive processing loop.
881 # Everyting else is simply a consequence of this loop!
883 while (jmp = callPrim(jmp)) != 0
884 println("Evaluating prim $jmp [$(primNames[-jmp])]")
890 function dump(startAddr::Int64; count::Int64 = 100, cellsPerLine::Int64 = 10)
891 chars = Array{Char,1}(cellsPerLine)
893 lineStartAddr = cellsPerLine*div((startAddr-1),cellsPerLine) + 1
894 endAddr = startAddr + count - 1
896 q, r = divrem((endAddr-lineStartAddr+1), cellsPerLine)
897 numLines = q + (r > 0 ? 1 : 0)
903 for c in 1:cellsPerLine
904 if i >= startAddr && i <= endAddr
906 if mem[i]>=32 && mem[i]<128
907 chars[c] = Char(mem[i])
919 println("\t", ASCIIString(chars))
924 count = reg.PSP - mem[PSP0]
928 for i in (mem[PSP0]+1):reg.PSP
933 println("Parameter stack empty")
938 count = reg.RSP - mem[RSP0]
942 for i in (mem[RSP0]+1):reg.RSP
947 println("Return stack empty")