module forth
-RS = Array{Int64, 1}(1024)
-RSP = 0
+# VM mem size
+size_mem = 1000000 # 1 mega-int
-PS = Array{Int64, 1}(1024)
-PSP =0
+# Buffer sizes
+size_RS = 1000 # Return stack size
+size_PS = 1000 # Parameter stack size
+size_TIB = 1000 # Terminal input buffer size
-IP = 0
-W = 0
-X = 0
+# The mem array constitutes the memory of the VM. It has the following geography:
+#
+# mem = +-----------------------+
+# | Built-in Variables |
+# +-----------------------+
+# | Return Stack |
+# +-----------------------+
+# | Parameter Stack |
+# +-----------------------+
+# | Terminal Input Buffer |
+# +-----------------------+
+# | Dictionary |
+# +-----------------------+
+#
+# Note that all words (user-defined, primitive, variables, etc) are included in
+# the dictionary.
+#
+# Simple linear addressing is used with one exception: references to primitive code
+# blocks, which are represented as anonymous functions, appear as negative indicies
+# into the primitives array which contains these functions.
-jmp = 0
+mem = Array{Int64,1}(size_mem)
+primitives = Array{Function,1}()
+primNames = Array{ASCIIString,1}()
-primitives = Array{Expr,1}()
-memory = Array{Int64,1}(64*1024)
-LATEST = 0
-HERE = 1
+# Built-in variables
+
+nextVarAddr = 1
+HERE = nextVarAddr; nextVarAddr += 1
+LATEST = nextVarAddr; nextVarAddr += 1
+
+RSP0 = nextVarAddr # bottom of RS
+PSP0 = RSP0 + size_RS # bottom of PS
+TIB = PSP0 + size_PS # address of terminal input buffer
+mem[HERE] = TIB + size_TIB # location of bottom of dictionary
+mem[LATEST] = 0 # no previous definition
+
+DICT = mem[HERE] # Save bottom of dictionary as constant
-# Intperpreter state
+# VM registers
+type Reg
+ RSP::Int64 # Return stack pointer
+ PSP::Int64 # Parameter/data stack pointer
+ IP::Int64 # Instruction pointer
+ W::Int64 # Working register
+end
+reg = Reg(RSP0, PSP0, 0, 0)
+
+# Stack manipulation functions
-STATE = 0
+type ParamStackUnderflow <: Exception end
+type ReturnStackUnderflow <: Exception end
-# Current radix
+Base.showerror(io::IO, ex::ParamStackUnderflow) = print(io, "Parameter stack underflow.")
+Base.showerror(io::IO, ex::ReturnStackUnderflow) = print(io, "Return stack underflow.")
-BASE = 10
+getRSDepth() = reg.RSP - RSP0
+getPSDepth() = reg.PSP - PSP0
-# Stack manipulation macros
+function ensurePSDepth(depth::Int64)
+ if getPSDepth()<depth
+ throw(ParamStackUnderflow())
+ end
+end
+
+function ensureRSDepth(depth::Int64)
+ if getRSDepth()<depth
+ throw(ReturnStackUnderflow())
+ end
+end
function pushRS(val::Int64)
- global RSP
- RS[RSP += 1] = val
+ mem[reg.RSP+=1] = val
end
function popRS()
- global RSP
- val = RS[RSP]
- RSP -= 1
+ ensureRSDepth(1)
+
+ val = mem[reg.RSP]
+ reg.RSP -= 1
return val
end
function pushPS(val::Int64)
- global PSP
- PS[PSP += 1] = val
+ mem[reg.PSP += 1] = val
end
function popPS()
- global PSP
- val = PS[PSP]
- PSP -= 1
+ ensurePSDepth(1)
+
+ val = mem[reg.PSP]
+ reg.PSP -= 1
return val
end
-# Primitive creation functions
+# Handy functions for adding/retrieving strings to/from memory.
+
+getString(addr::Int64, len::Int64) = ASCIIString([Char(c) for c in mem[addr:(addr+len-1)]])
+
+function putString(str::ASCIIString, addr::Int64)
+ mem[addr:(addr+length(str)-1)] = [Int64(c) for c in str]
+end
+
+# Primitive creation and calling functions
+
+function defPrim(f::Function; name="nameless")
+ push!(primitives, f)
+ push!(primNames, replace(name, "\004", "EOF"))
+
+ return -length(primitives)
+end
-function defPrim(name::AbstractString, expr::Expr)
- global HERE, LATEST
+function callPrim(addr::Int64)
+ if addr >=0 || -addr>length(primitives)
+ error("Attempted to execute non-existent primitive at address $addr.")
+ else
+ primitives[-addr]()
+ end
+end
+getPrimName(addr::Int64) = primNames[-addr]
- memory[HERE] = LATEST
- LATEST = HERE
- HERE += 1
+# Word creation functions
- memory[HERE] = length(name); HERE += 1
- memory[HERE:(HERE+length(name)-1)] = [Int(c) for c in name]; HERE += length(name)
+F_IMMED = 128
+F_HIDDEN = 256
+F_LENMASK = 127
- push!(primitives, expr)
- memory[HERE] = -length(primitives)
- codeword = HERE
- HERE += 1
+function createHeader(name::AbstractString, flags::Int64)
+ mem[mem[HERE]] = mem[LATEST]
+ mem[LATEST] = mem[HERE]
+ mem[HERE] += 1
- return codeword
+ mem[mem[HERE]] = length(name) | flags; mem[HERE] += 1
+ putString(name, mem[HERE]); mem[HERE] += length(name)
end
-defVar(name::AbstractString, var::Expr) = defPrim(name, Expr(:call, :pushPS, var))
-defConst(name::AbstractString, val::Int64) = defPrim(name, Expr(:call, :pushPS, :val))
+function defPrimWord(name::AbstractString, f::Function; flags::Int64=0)
+ createHeader(name, flags)
-# Threading Primitives
+ codeWordAddr = mem[HERE]
+ mem[codeWordAddr] = defPrim(f, name=name)
+ mem[HERE] += 1
-NEXT = defPrim("NEXT", :(begin
- W = memory[IP]
- IP += 1
- X = memory[W]
- jmp = X
-end))
+ return codeWordAddr
+end
-DOCOL = defPrim("DOCOL", :(begin
- pushRS(IP)
- IP = W + 1
- jmp = NEXT
-end))
+function defWord(name::AbstractString, wordAddrs::Array{Int64,1}; flags::Int64=0)
+ createHeader(name, flags)
-EXIT = defPrim("EXIT", :(begin
- IP = popRS()
- jmp = NEXT
-end))
+ addr = mem[HERE]
+ mem[mem[HERE]] = DOCOL
+ mem[HERE] += 1
+
+ for wordAddr in wordAddrs
+ mem[mem[HERE]] = wordAddr
+ mem[HERE] += 1
+ end
+
+ return addr
+end
+
+# Variable creation functions
+function defExistingVar(name::AbstractString, varAddr::Int64; flags::Int64=0)
+
+ defPrimWord(name, eval(:(() -> begin
+ pushPS($(varAddr))
+ return NEXT
+ end)))
+end
+
+function defNewVar(name::AbstractString, initial::Int64; flags::Int64=0)
+ createHeader(name, flags)
+
+ codeWordAddr = mem[HERE]
+ varAddr = mem[HERE] + 1
+
+ mem[mem[HERE]] = DOVAR; mem[HERE] += 1
+ mem[mem[HERE]] = initial; mem[HERE] += 1
+
+ return varAddr, codeWordAddr
+end
+
+function defConst(name::AbstractString, val::Int64; flags::Int64=0)
+ createHeader(name, flags)
+
+ codeWordAddr = mem[HERE]
+
+ mem[mem[HERE]] = DOCON; mem[HERE] += 1
+ mem[mem[HERE]] = val; mem[HERE] += 1
+
+ return codeWordAddr
+end
+
+# Threading Primitives (inner interpreter)
+
+NEXT = defPrim(() -> begin
+ reg.W = mem[reg.IP]
+ reg.IP += 1
+ return mem[reg.W]
+end, name="NEXT")
+
+DOCOL = defPrim(() -> begin
+ pushRS(reg.IP)
+ reg.IP = reg.W + 1
+ return NEXT
+end, name="DOCOL")
+
+DOVAR = defPrim(() -> begin
+ pushPS(reg.W + 1)
+ return NEXT
+end, name="DOVAR")
+
+DOCON = defPrim(() -> begin
+ pushPS(mem[reg.W + 1])
+ return NEXT
+end, name="DOVAR")
+
+EXIT = defPrimWord("EXIT", () -> begin
+ reg.IP = popRS()
+ return NEXT
+end)
+
+# Dictionary entries for core built-in variables, constants
+
+HERE_CFA = defExistingVar("HERE", HERE)
+LATEST_CFA = defExistingVar("LATEST", LATEST)
+
+PSP0_CFA = defConst("PSP0", PSP0)
+RSP0_CFA = defConst("RSP0", RSP0)
+
+defConst("DOCOL", DOCOL)
+defConst("DOCON", DOCON)
+defConst("DOVAR", DOVAR)
+
+defConst("DICT", DICT)
+defConst("MEMSIZE", size_mem)
+
+F_IMMED_CFA = defConst("F_IMMED", F_IMMED)
+F_HIDDEN_CFA = defConst("F_HIDDEN", F_HIDDEN)
+F_LENMASK_CFA = defConst("F_LENMASK", F_LENMASK)
# Basic forth primitives
-DROP = defPrim("DROP", :(begin
+DROP = defPrimWord("DROP", () -> begin
popPS()
- jmp = NEXT
-end))
+ return NEXT
+end)
-SWAP = defPrim("SWAP", :(begin
- PS[PSP], PS[PSP-1] = PS[PSP-1], PS[PS]
- jmp = NEXT
-end))
+SWAP = defPrimWord("SWAP", () -> begin
+ a = popPS()
+ b = popPS()
+ pushPS(a)
+ pushPS(b)
+ return NEXT
+end)
-DUP = defPrim("DUP", :(begin
- pushPS(PS[PSP])
- jmp = NEXT
-end))
+DUP = defPrimWord("DUP", () -> begin
+ ensurePSDepth(1)
+ pushPS(mem[reg.PSP])
+ return NEXT
+end)
-LIT = defPrim("LIT", :(begin
- pushPS(memory[IP])
- IP += 1
- jmp = NEXT
-end))
+OVER = defPrimWord("OVER", () -> begin
+ ensurePSDepth(2)
+ pushPS(mem[reg.PSP-1])
+ return NEXT
+end)
+
+ROT = defPrimWord("ROT", () -> begin
+ a = popPS()
+ b = popPS()
+ c = popPS()
+ pushPS(b)
+ pushPS(a)
+ pushPS(c)
+ return NEXT
+end)
+
+NROT = defPrimWord("-ROT", () -> begin
+ a = popPS()
+ b = popPS()
+ c = popPS()
+ pushPS(a)
+ pushPS(c)
+ pushPS(b)
+ return NEXT
+end)
+
+
+TWODROP = defPrimWord("2DROP", () -> begin
+ popPS()
+ popPS()
+ return NEXT
+end)
+
+TWODUP = defPrimWord("2DUP", () -> begin
+ ensurePSDepth(2)
+ a = mem[reg.PSP-1]
+ b = mem[reg.PSP]
+ pushPS(a)
+ pushPS(b)
+ return NEXT
+end)
+
+TWOSWAP = defPrimWord("2SWAP", () -> begin
+ a = popPS()
+ b = popPS()
+ c = popPS()
+ d = popPS()
+ pushPS(b)
+ pushPS(a)
+ pushPS(d)
+ pushPS(c)
+ return NEXT
+end)
+
+TWOOVER = defPrimWord("2OVER", () -> begin
+ ensurePSDepth(4)
+ a = mem[reg.PSP-3]
+ b = mem[reg.PSP-2]
+ pushPS(a)
+ pushPS(b)
+ return NEXT
+end)
+
+QDUP = defPrimWord("?DUP", () -> begin
+ ensurePSDepth(1)
+ val = mem[reg.PSP]
+ if val != 0
+ pushPS(val)
+ end
+ return NEXT
+end)
+
+INCR = defPrimWord("1+", () -> begin
+ ensurePSDepth(1)
+ mem[reg.PSP] += 1
+ return NEXT
+end)
+
+DECR = defPrimWord("1-", () -> begin
+ ensurePSDepth(1)
+ mem[reg.PSP] -= 1
+ return NEXT
+end)
+
+INCR2 = defPrimWord("2+", () -> begin
+ ensurePSDepth(1)
+ mem[reg.PSP] += 2
+ return NEXT
+end)
+
+DECR2 = defPrimWord("2-", () -> begin
+ ensurePSDepth(1)
+ mem[reg.PSP] -= 2
+ return NEXT
+end)
+
+ADD = defPrimWord("+", () -> begin
+ b = popPS()
+ a = popPS()
+ pushPS(a+b)
+ return NEXT
+end)
+
+SUB = defPrimWord("-", () -> begin
+ b = popPS()
+ a = popPS()
+ pushPS(a-b)
+ return NEXT
+end)
+
+MUL = defPrimWord("*", () -> begin
+ b = popPS()
+ a = popPS()
+ pushPS(a*b)
+ return NEXT
+end)
+
+DIVMOD = defPrimWord("/MOD", () -> begin
+ b = popPS()
+ a = popPS()
+ q,r = divrem(a,b)
+ pushPS(r)
+ pushPS(q)
+ return NEXT
+end)
+
+TWOMUL = defPrimWord("2*", () -> begin
+ pushPS(popPS() << 1)
+ return NEXT
+end)
+
+TWODIV = defPrimWord("2/", () -> begin
+ pushPS(popPS() >> 1)
+ return NEXT
+end)
+
+EQ = defPrimWord("=", () -> begin
+ b = popPS()
+ a = popPS()
+ pushPS(a==b ? -1 : 0)
+ return NEXT
+end)
+
+NE = defPrimWord("<>", () -> begin
+ b = popPS()
+ a = popPS()
+ pushPS(a!=b ? -1 : 0)
+ return NEXT
+end)
+
+LT = defPrimWord("<", () -> begin
+ b = popPS()
+ a = popPS()
+ pushPS(a<b ? -1 : 0)
+ return NEXT
+end)
+
+GT = defPrimWord(">", () -> begin
+ b = popPS()
+ a = popPS()
+ pushPS(a>b ? -1 : 0)
+ return NEXT
+end)
+
+LE = defPrimWord("<=", () -> begin
+ b = popPS()
+ a = popPS()
+ pushPS(a<=b ? -1 : 0)
+ return NEXT
+end)
+
+GE = defPrimWord(">=", () -> begin
+ b = popPS()
+ a = popPS()
+ pushPS(a>=b ? -1 : 0)
+ return NEXT
+end)
+
+ZE = defPrimWord("0=", () -> begin
+ pushPS(popPS() == 0 ? -1 : 0)
+ return NEXT
+end)
+
+ZNE = defPrimWord("0<>", () -> begin
+ pushPS(popPS() != 0 ? -1 : 0)
+ return NEXT
+end)
+
+ZLT = defPrimWord("0<", () -> begin
+ pushPS(popPS() < 0 ? -1 : 0)
+ return NEXT
+end)
+
+ZGT = defPrimWord("0>", () -> begin
+ pushPS(popPS() > 0 ? -1 : 0)
+ return NEXT
+end)
+
+ZLE = defPrimWord("0<=", () -> begin
+ pushPS(popPS() <= 0 ? -1 : 0)
+ return NEXT
+end)
+
+ZGE = defPrimWord("0>=", () -> begin
+ pushPS(popPS() >= 0 ? -1 : 0)
+ return NEXT
+end)
+
+AND = defPrimWord("AND", () -> begin
+ b = popPS()
+ a = popPS()
+ pushPS(a & b)
+ return NEXT
+end)
+
+OR = defPrimWord("OR", () -> begin
+ b = popPS()
+ a = popPS()
+ pushPS(a | b)
+ return NEXT
+end)
+
+XOR = defPrimWord("XOR", () -> begin
+ b = popPS()
+ a = popPS()
+ pushPS(a $ b)
+ return NEXT
+end)
+
+INVERT = defPrimWord("INVERT", () -> begin
+ pushPS(~popPS())
+ return NEXT
+end)
+
+# Literals
+
+LIT = defPrimWord("LIT", () -> begin
+ pushPS(mem[reg.IP])
+ reg.IP += 1
+ return NEXT
+end)
# Memory primitives
-STORE = defPrim("!", :(begin
+STORE = defPrimWord("!", () -> begin
addr = popPS()
dat = popPS()
- memory[addr] = dat
- jmp = NEXT
-end))
+ mem[addr] = dat
+ return NEXT
+end)
-FETCH = defPrim("@", :(begin
+FETCH = defPrimWord("@", () -> begin
addr = popPS()
- pushPS(memory[addr])
- jmp = NEXT
-end))
+ pushPS(mem[addr])
+ return NEXT
+end)
-ADDSTORE = defPrim("+!", :(begin
+ADDSTORE = defPrimWord("+!", () -> begin
addr = popPS()
toAdd = popPS()
- memory[addr] += toAdd
- jmp = NEXT
-end))
+ mem[addr] += toAdd
+ return NEXT
+end)
-SUBSTORE = defPrim("-!", :(begin
+SUBSTORE = defPrimWord("-!", () -> begin
addr = popPS()
toSub = popPS()
- memory[addr] -= toSub
- jmp = NEXT
-end))
+ mem[addr] -= toSub
+ return NEXT
+end)
-# Built-in variables
+# Return Stack
-defVar("STATE", :STATE)
-defVar("HERE", :HERE)
-defVar("LATEST", :LATEST)
-defVAR("BASE", :BASE)
+TOR = defPrimWord(">R", () -> begin
+ pushRS(popPS())
+ return NEXT
+end)
-# Constants
+FROMR = defPrimWord("R>", () -> begin
+ pushPS(popRS())
+ return NEXT
+end)
-defConst("VERSION", 1)
-defConst("DOCOL", DOCOL)
+RFETCH = defPrimWord("R@", () -> begin
+ pushPS(mem[reg.RSP])
+ return NEXT
+end)
-# Return Stack
+RSPFETCH = defPrimWord("RSP@", () -> begin
+ pushPS(reg.RSP)
+ return NEXT
+end)
-TOR = defPrim(">R", :(pushRS(popPS())))
-FROMR = defPrim("R>", :(pushPS(popRS())))
-RSPFETCH = defPrim("RSP@", :(pushPS(RSP)))
-RSPSTORE = defPrim("RSP!", :(RSP = popPS()))
-RDROP = defPrim("RDROP", :(popRS()))
+RSPSTORE = defPrimWord("RSP!", () -> begin
+ reg.RSP = popPS()
+ return NEXT
+end)
+
+RDROP = defPrimWord("RDROP", () -> begin
+ popRS()
+ return NEXT
+end)
# Parameter Stack
-PSPFETCH = defPrim("PSP@", :(pushPS(PSP)))
-PSPSTORE = defPrim("PSP!", :(PSP = popPS()))
+PSPFETCH = defPrimWord("PSP@", () -> begin
+ pushPS(reg.PSP)
+ return NEXT
+end)
+
+PSPSTORE = defPrimWord("PSP!", () -> begin
+ reg.PSP = popPS()
+ return NEXT
+end)
+
+# Working Register
+
+WFETCH = defPrimWord("W@", () -> begin
+ pushPS(reg.W)
+ return NEXT
+end)
+
+WSTORE = defPrimWord("W!", () -> begin
+ reg.W = popPS()
+ return NEXT
+end)
+
+# I/O
+
+sources = Array{Any,1}()
+currentSource() = sources[length(sources)]
+
+EOF = defPrimWord("\x04", () -> begin
+ close(pop!(sources))
+ if !isempty(sources)
+ return NEXT
+ else
+ return 0
+ end
+end)
+
+EMIT = defPrimWord("EMIT", () -> begin
+ print(Char(popPS()))
+ return NEXT
+end)
+
+SPAN, SPAN_CFA = defNewVar("SPAN", 0)
+EXPECT = defPrimWord("EXPECT", () -> begin
+ maxLen = popPS()
+ addr = popPS()
+
+ if !eof(currentSource())
+ line = chomp(readline(currentSource()))
+ mem[SPAN] = min(length(line), maxLen)
+ putString(line[1:mem[SPAN]], addr)
+ else
+ mem[SPAN] = 1
+ mem[addr] = 4 # eof
+ end
+
+ return NEXT
+end)
-# VM loop
-jmp = NEXT
-function runVM()
- while true
- eval(primitives[-memory[jmp]])
+BASE, BASE_CFA = defNewVar("BASE", 10)
+NUMBER = defPrimWord("NUMBER", () -> begin
+ wordAddr = popPS()+1
+ wordLen = mem[wordAddr-1]
+
+ s = getString(wordAddr, wordLen)
+
+ pushPS(parse(Int64, s, mem[BASE]))
+
+ return NEXT
+end)
+
+# Dictionary searches
+
+FIND = defPrimWord("FIND", () -> begin
+
+ countedAddr = popPS()
+ wordAddr = countedAddr + 1
+ wordLen = mem[countedAddr]
+ word = lowercase(getString(wordAddr, wordLen))
+
+ latest = LATEST
+
+ i = 0
+ while (latest = mem[latest]) > 0
+ lenAndFlags = mem[latest+1]
+ len = lenAndFlags & F_LENMASK
+ hidden = (lenAndFlags & F_HIDDEN) == F_HIDDEN
+
+ if hidden || len != wordLen
+ continue
+ end
+
+ thisAddr = latest+2
+ thisWord = lowercase(getString(thisAddr, len))
+
+ if lowercase(thisWord) == lowercase(word)
+ break
+ end
+ end
+
+ pushPS(latest)
+
+ return NEXT
+end)
+
+TOCFA = defPrimWord(">CFA", () -> begin
+
+ addr = popPS()
+ lenAndFlags = mem[addr+1]
+ len = lenAndFlags & F_LENMASK
+
+ pushPS(addr + 2 + len)
+
+ return NEXT
+end)
+
+TOPFA = defWord(">PFA", [TOCFA, INCR, EXIT])
+
+# Branching
+
+BRANCH = defPrimWord("BRANCH", () -> begin
+ reg.IP += mem[reg.IP]
+ return NEXT
+end)
+
+ZBRANCH = defPrimWord("0BRANCH", () -> begin
+ if (popPS() == 0)
+ reg.IP += mem[reg.IP]
+ else
+ reg.IP += 1
+ end
+
+ return NEXT
+end)
+
+# Strings
+
+LITSTRING = defPrimWord("LITSTRING", () -> begin
+ len = mem[reg.IP]
+ reg.IP += 1
+ pushPS(reg.IP)
+ pushPS(len)
+ reg.IP += len
+
+ return NEXT
+end)
+
+TYPE = defPrimWord("TYPE", () -> begin
+ len = popPS()
+ addr = popPS()
+ str = getString(addr, len)
+ print(str)
+ return NEXT
+end)
+
+# Outer interpreter
+
+TRACE = defPrimWord("TRACE", () -> begin
+ println("reg.W: $(reg.W) reg.IP: $(reg.IP)")
+ print("PS: "); printPS()
+ print("RS: "); printRS()
+ print("[paused]")
+ readline()
+
+ return NEXT
+end)
+
+COMMA = defPrimWord(",", () -> begin
+ mem[mem[HERE]] = popPS()
+ mem[HERE] += 1
+
+ return NEXT
+end)
+
+BTICK = defWord("[']",
+ [FROMR, DUP, INCR, TOR, FETCH, EXIT])
+
+EXECUTE = defPrimWord("EXECUTE", () -> begin
+ reg.W = popPS()
+ return mem[reg.W]
+end)
+
+TIB_CFA = defConst("TIB", TIB)
+NUMTIB, NUMTIB_CFA = defNewVar("#TIB", 0)
+TOIN, TOIN_CFA = defNewVar(">IN", 0)
+
+QUERY = defWord("QUERY",
+ [TIB_CFA, LIT, 160, EXPECT,
+ SPAN_CFA, FETCH, NUMTIB_CFA, STORE,
+ LIT, 0, TOIN_CFA, STORE,
+ EXIT])
+
+WORD = defPrimWord("WORD", () -> begin
+ delim = popPS()
+
+ # Chew up initial occurrences of delim
+ while (mem[TOIN]<mem[NUMTIB] && mem[TIB+mem[TOIN]] == delim)
+ mem[TOIN] += 1
+ end
+
+ countAddr = mem[HERE]
+ addr = mem[HERE]+1
+
+ # Start reading in word
+ count = 0
+ while (mem[TOIN]<mem[NUMTIB])
+ mem[addr] = mem[TIB+mem[TOIN]]
+ mem[TOIN] += 1
+
+ if (mem[addr] == delim)
+ break
+ end
+
+ count += 1
+ addr += 1
+ end
+
+ # Record count
+ mem[countAddr] = count
+ pushPS(countAddr)
+
+ return NEXT
+end)
+
+PARSE = defPrimWord("PARSE", () -> begin
+ delim = popPS()
+
+ # Chew up initial occurrences of delim
+ addr = mem[HERE]
+
+ # Start reading input stream
+ count = 0
+ while (mem[TOIN]<mem[NUMTIB])
+ mem[addr] = mem[TIB+mem[TOIN]]
+ mem[TOIN] += 1
+
+ if (mem[addr] == delim)
+ break
+ end
+
+ count += 1
+ addr += 1
+ end
+
+ pushPS(addr)
+ pushPS(count)
+
+ return NEXT
+end)
+
+BYE = defPrimWord("BYE", () -> begin
+ println("Bye!")
+ return 0
+end)
+
+STATE, STATE_CFA = defNewVar("STATE", 0)
+
+INTERPRET = defWord("INTERPRET",
+ [LIT, 32, WORD, # Read next space-delimited word
+
+ DUP, FETCH, ZE, ZBRANCH, 3,
+ DROP, EXIT, # Exit if TIB is exhausted
+
+ STATE_CFA, FETCH, ZBRANCH, 31,
+ # Compiling
+ DUP, FIND, QDUP, ZBRANCH, 19,
+
+ # Found word.
+ SWAP, DROP,
+ DUP, TOCFA, SWAP, INCR, FETCH, LIT, F_IMMED, AND, ZBRANCH, 4,
+ # Immediate: Execute!
+ EXECUTE, BRANCH, -33,
+
+ # Not immediate: Compile!
+ COMMA, BRANCH, -36,
+
+ # No word found, parse number
+ NUMBER, BTICK, LIT, COMMA, COMMA, BRANCH, -43,
+
+ # Interpreting
+ DUP, FIND, QDUP, ZBRANCH, 7,
+
+ # Found word. Execute!
+ SWAP, DROP, TOCFA, EXECUTE, BRANCH, -54,
+
+ # No word found, parse number and leave on stack
+ NUMBER, BRANCH, -57,
+ EXIT]
+)
+
+PROMPT = defPrimWord("PROMPT", () -> begin
+ if (mem[STATE] == 0 && currentSource() == STDIN)
+ println(" ok")
+ end
+
+ return NEXT
+end)
+
+QUIT = defWord("QUIT",
+ [LIT, 0, STATE_CFA, STORE,
+ LIT, 0, NUMTIB_CFA, STORE,
+ RSP0_CFA, RSPSTORE,
+ QUERY,
+ INTERPRET, PROMPT,
+ BRANCH,-4])
+
+ABORT = defWord("ABORT",
+ [PSP0_CFA, PSPSTORE, QUIT])
+
+INCLUDE = defPrimWord("INCLUDE", () -> begin
+ pushPS(32)
+ callPrim(mem[WORD])
+ wordAddr = popPS()+1
+ wordLen = mem[wordAddr-1]
+ word = getString(wordAddr, wordLen)
+
+ push!(sources, open(word, "r"))
+
+ # Clear input buffer
+ mem[NUMTIB] = 0
+
+ return NEXT
+end)
+
+# Compilation
+
+HEADER = defPrimWord("HEADER", () -> begin
+ wordAddr = popPS()+1
+ wordLen = mem[wordAddr-1]
+ word = getString(wordAddr, wordLen)
+
+ createHeader(word, 0)
+
+ return NEXT
+end)
+
+LBRAC = defPrimWord("[", () -> begin
+ mem[STATE] = 0
+ return NEXT
+end, flags=F_IMMED)
+
+RBRAC = defPrimWord("]", () -> begin
+ mem[STATE] = 1
+ return NEXT
+end, flags=F_IMMED)
+
+HIDDEN = defPrimWord("HIDDEN", () -> begin
+ addr = popPS() + 1
+ mem[addr] = mem[addr] $ F_HIDDEN
+ return NEXT
+end)
+
+HIDE = defWord("HIDE",
+ [LIT, 32, WORD,
+ FIND,
+ HIDDEN,
+ EXIT])
+
+COLON = defWord(":",
+ [LIT, 32, WORD,
+ HEADER,
+ LIT, DOCOL, COMMA,
+ LATEST_CFA, FETCH, HIDDEN,
+ RBRAC,
+ EXIT])
+
+SEMICOLON = defWord(";",
+ [LIT, EXIT, COMMA,
+ LATEST_CFA, FETCH, HIDDEN,
+ LBRAC,
+ EXIT], flags=F_IMMED)
+
+IMMEDIATE = defPrimWord("IMMEDIATE", () -> begin
+ lenAndFlagsAddr = mem[LATEST] + 1
+ mem[lenAndFlagsAddr] = mem[lenAndFlagsAddr] $ F_IMMED
+ return NEXT
+end, flags=F_IMMED)
+
+
+#### VM loop ####
+
+initialized = false
+initFileName = nothing
+if isfile("lib.4th")
+ initFileName = "lib.4th"
+elseif isfile(Pkg.dir("forth/src/lib.4th"))
+ initFileName = Pkg.dir("forth/src/lib.4th")
+end
+
+function run(;initialize=true)
+ # Begin with STDIN as source
+ push!(sources, STDIN)
+
+ global initialized, initFileName
+ if !initialized && initialize
+ if initFileName != nothing
+ print("Including definitions from $initFileName...")
+ push!(sources, open(initFileName, "r"))
+ initialized = true
+ else
+ println("No library file found. Only primitive words available.")
+ end
+ end
+
+ # Start with IP pointing to first instruction of outer interpreter
+ reg.IP = QUIT + 1
+
+ # Primitive processing loop.
+ # Everyting else is simply a consequence of this loop!
+ jmp = NEXT
+ while jmp != 0
+ try
+ #println("Entering prim $(getPrimName(jmp))")
+ jmp = callPrim(jmp)
+
+ catch ex
+ showerror(STDOUT, ex)
+ println()
+
+ while !isempty(sources) && currentSource() != STDIN
+ close(pop!(sources))
+ end
+
+ # QUIT
+ reg.IP = ABORT + 1
+ jmp = NEXT
+ end
+ end
+end
+
+# Debugging tools
+
+function dump(startAddr::Int64; count::Int64 = 100, cellsPerLine::Int64 = 10)
+ chars = Array{Char,1}(cellsPerLine)
+
+ lineStartAddr = cellsPerLine*div((startAddr-1),cellsPerLine) + 1
+ endAddr = startAddr + count - 1
+
+ q, r = divrem((endAddr-lineStartAddr+1), cellsPerLine)
+ numLines = q + (r > 0 ? 1 : 0)
+
+ i = lineStartAddr
+ for l in 1:numLines
+ print(i,":")
+
+ for c in 1:cellsPerLine
+ if i >= startAddr && i <= endAddr
+ print("\t",mem[i])
+ if mem[i]>=32 && mem[i]<128
+ chars[c] = Char(mem[i])
+ else
+ chars[c] = '.'
+ end
+ else
+ print("\t")
+ chars[c] = ' '
+ end
+
+ i += 1
+ end
+
+ println("\t", ASCIIString(chars))
+ end
+end
+
+function printPS()
+ count = reg.PSP - PSP0
+
+ if count > 0
+ print("<$count>")
+ for i in (PSP0+1):reg.PSP
+ print(" $(mem[i])")
+ end
+ println()
+ else
+ println("Parameter stack empty")
end
end
+function printRS()
+ count = reg.RSP - RSP0
+
+ if count > 0
+ print("<$count>")
+ for i in (RSP0+1):reg.RSP
+ print(" $(mem[i])")
+ end
+ println()
+ else
+ println("Return stack empty")
+ end
+end
+
+DUMP = defPrimWord("DUMP", () -> begin
+ count = popPS()
+ addr = popPS()
+
+ dump(addr, count=count)
+
+ return NEXT
+end)
+
end
The Lambda Lab / projects / forth.jl.git / blobdiff