module forth
# VM mem size
-size_mem = 640*1024
+size_mem = 1000000 # 1 mega-int
# Buffer sizes
-size_RS = 1024 # Return stack size
-size_PS = 1024 # Parameter stack size
-size_TIB = 1096 # Terminal input buffer size
+size_RS = 1000 # Return stack size
+size_PS = 1000 # Parameter stack size
+size_TIB = 1000 # Terminal input buffer size
# The mem array constitutes the memory of the VM. It has the following geography:
#
# Built-in variables
nextVarAddr = 1
-RSP0 = nextVarAddr; nextVarAddr += 1
-PSP0 = nextVarAddr; nextVarAddr += 1
HERE = nextVarAddr; nextVarAddr += 1
LATEST = nextVarAddr; nextVarAddr += 1
-mem[RSP0] = nextVarAddr # bottom of RS
-mem[PSP0] = mem[RSP0] + size_RS # bottom of PS
-TIB = mem[PSP0] + size_PS # address of terminal input buffer
-mem[HERE] = TIB + size_TIB # location of bottom of dictionary
-mem[LATEST] = 0 # no previous definition
+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
IP::Int64 # Instruction pointer
W::Int64 # Working register
end
-reg = Reg(mem[RSP0], mem[PSP0], 0, 0)
+reg = Reg(RSP0, PSP0, 0, 0)
# Stack manipulation functions
Base.showerror(io::IO, ex::ParamStackUnderflow) = print(io, "Parameter stack underflow.")
Base.showerror(io::IO, ex::ReturnStackUnderflow) = print(io, "Return stack underflow.")
-getRSDepth() = reg.RSP - mem[RSP0]
-getPSDepth() = reg.PSP - mem[PSP0]
+getRSDepth() = reg.RSP - RSP0
+getPSDepth() = reg.PSP - PSP0
function ensurePSDepth(depth::Int64)
if getPSDepth()<depth
# 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
function defPrim(f::Function; name="nameless")
push!(primitives, f)
- push!(primNames, replace(replace(name, "\004", "EOF"), "\n", "\\n"))
+ push!(primNames, replace(name, "\004", "EOF"))
return -length(primitives)
end
-callPrim(addr::Int64) = primitives[-addr]()
+function callPrim(addr::Int64)
+ if addr >=0 || -addr>length(primitives)
+ error("Attempted to execute non-existent primitive at address $addr.")
+ else
+ primitives[-addr]()
+ end
+end
+getPrimName(addr::Int64) = primNames[-addr]
+
+# Word creation functions
-# Word creation
+F_IMMED = 128
+F_HIDDEN = 256
+F_LENMASK = 127
function createHeader(name::AbstractString, flags::Int64)
mem[mem[HERE]] = mem[LATEST]
return addr
end
-# Variable creation
+# Variable creation functions
function defExistingVar(name::AbstractString, varAddr::Int64; flags::Int64=0)
codeWordAddr = mem[HERE]
varAddr = mem[HERE] + 1
- f = eval(:(() -> begin
- pushPS($(varAddr))
- return NEXT
- end))
-
- mem[mem[HERE]] = defPrim(f, name=name); 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)
- defPrimWord(name, eval(:(() -> begin
- pushPS($(val))
- return NEXT
- end)))
+ createHeader(name, flags)
- return val
+ codeWordAddr = mem[HERE]
+
+ mem[mem[HERE]] = DOCON; mem[HERE] += 1
+ mem[mem[HERE]] = val; mem[HERE] += 1
+
+ return codeWordAddr
end
# Threading Primitives (inner interpreter)
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 = defPrimWord("DROP", () -> begin
return NEXT
end)
-EQU = defPrimWord("=", () -> begin
+EQ = defPrimWord("=", () -> begin
b = popPS()
a = popPS()
pushPS(a==b ? -1 : 0)
return NEXT
end)
-NEQU = defPrimWord("<>", () -> begin
+NE = defPrimWord("<>", () -> begin
b = popPS()
a = popPS()
pushPS(a!=b ? -1 : 0)
return NEXT
end)
-ZEQU = defPrimWord("0=", () -> begin
+ZE = defPrimWord("0=", () -> begin
pushPS(popPS() == 0 ? -1 : 0)
return NEXT
end)
-ZNEQU = defPrimWord("0<>", () -> begin
+ZNE = defPrimWord("0<>", () -> begin
pushPS(popPS() != 0 ? -1 : 0)
return NEXT
end)
end)
-# Built-in variables
-
-HERE_CFA = defExistingVar("HERE", HERE)
-LATEST_CFA = defExistingVar("LATEST", LATEST)
-PSP0_CFA = defExistingVar("PSP0", PSP0)
-RSP0_CFA = defExistingVar("RSP0", RSP0)
-STATE, STATE_CFA = defNewVar("STATE", 0)
-BASE, BASE_CFA = defNewVar("BASE", 10)
-
-# Constants
-
-defConst("VERSION", 1)
-defConst("DOCOL", DOCOL)
-defConst("DICT", DICT)
-F_IMMED = defConst("F_IMMED", 128)
-F_HIDDEN = defConst("F_HIDDEN", 256)
-F_LENMASK = defConst("F_LENMASK", 127)
-
# Return Stack
TOR = defPrimWord(">R", () -> begin
end)
RSPSTORE = defPrimWord("RSP!", () -> begin
- RSP = popPS()
+ reg.RSP = popPS()
return NEXT
end)
end)
PSPSTORE = defPrimWord("PSP!", () -> begin
- PSP = popPS()
+ reg.PSP = popPS()
return NEXT
end)
sources = Array{Any,1}()
currentSource() = sources[length(sources)]
-defConst("TIB", TIB)
-NUMTIB, NUMTIB_CFA = defNewVar("#TIB", 0)
-TOIN, TOIN_CFA = defNewVar(">IN", 0)
-EOF = defConst("EOF", 4)
-
-KEY = defPrimWord("KEY", () -> begin
- if mem[TOIN] >= mem[NUMTIB]
- mem[TOIN] = 0
-
- if !eof(currentSource())
- line = readline(currentSource())
- mem[NUMTIB] = length(line)
- putString(line, TIB)
- else
- mem[NUMTIB] = 1
- mem[TIB] = EOF
- end
+EOF = defPrimWord("\x04", () -> begin
+ close(pop!(sources))
+ if !isempty(sources)
+ return NEXT
+ else
+ return 0
end
-
- pushPS(mem[TIB + mem[TOIN]])
- mem[TOIN] += 1
-
- return NEXT
end)
EMIT = defPrimWord("EMIT", () -> begin
return NEXT
end)
-WORD = defPrimWord("WORD", () -> begin
-
- eof_char = Char(EOF)
- c = eof_char
-
- skip_to_end = false
- while true
-
- callPrim(mem[KEY])
- c = Char(popPS())
-
- if c == '\\'
- skip_to_end = true
- continue
- end
-
- if skip_to_end
- if c == '\n' || c == eof_char
- skip_to_end = false
- end
- continue
- end
-
- if c == ' ' || c == '\t'
- continue
- end
-
- break
- end
-
- wordAddr = mem[HERE]
- offset = 0
-
- if c == '\n' || c == eof_char
- # Treat newline as a special word
-
- mem[wordAddr + offset] = Int64(c)
- pushPS(wordAddr)
- pushPS(1)
- return NEXT
- end
-
- while true
- mem[wordAddr + offset] = Int64(c)
- offset += 1
-
- callPrim(mem[KEY])
- c = Char(popPS())
+SPAN, SPAN_CFA = defNewVar("SPAN", 0)
+EXPECT = defPrimWord("EXPECT", () -> begin
+ maxLen = popPS()
+ addr = popPS()
- if c == ' ' || c == '\t' || c == '\n' || c == eof_char
- # Rewind KEY
- mem[TOIN] -= 1
- break
- end
+ 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
- wordLen = offset
-
- pushPS(wordAddr)
- pushPS(wordLen)
-
return NEXT
end)
+BASE, BASE_CFA = defNewVar("BASE", 10)
NUMBER = defPrimWord("NUMBER", () -> begin
-
- wordLen = popPS()
- wordAddr = popPS()
+ wordAddr = popPS()+1
+ wordLen = mem[wordAddr-1]
s = getString(wordAddr, wordLen)
- try
- pushPS(parse(Int64, s, mem[BASE]))
- pushPS(0)
- catch
- pushPS(1) # Error indication
- end
+ pushPS(parse(Int64, s, mem[BASE]))
return NEXT
end)
FIND = defPrimWord("FIND", () -> begin
- wordLen = popPS()
- wordAddr = popPS()
+ countedAddr = popPS()
+ wordAddr = countedAddr + 1
+ wordLen = mem[countedAddr]
word = lowercase(getString(wordAddr, wordLen))
latest = LATEST
return NEXT
end)
-TODFA = defWord(">DFA", [TOCFA, INCR, EXIT])
+TOPFA = defWord(">PFA", [TOCFA, INCR, EXIT])
# Branching
return NEXT
end)
-# Compilation
+# Strings
-CREATE = defPrimWord("CREATE", () -> begin
+LITSTRING = defPrimWord("LITSTRING", () -> begin
+ len = mem[reg.IP]
+ reg.IP += 1
+ pushPS(reg.IP)
+ pushPS(len)
+ reg.IP += len
- wordLen = popPS()
- wordAddr = popPS()
- word = getString(wordAddr, wordLen)
+ return NEXT
+end)
- createHeader(word, 0)
+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)
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)
+BTICK = defWord("[']",
+ [FROMR, DUP, INCR, TOR, FETCH, EXIT])
-HIDDEN = defPrimWord("HIDDEN", () -> begin
- addr = popPS() + 1
- mem[addr] = mem[addr] $ F_HIDDEN
- return NEXT
+EXECUTE = defPrimWord("EXECUTE", () -> begin
+ reg.W = popPS()
+ return mem[reg.W]
end)
-HIDE = defWord("HIDE",
- [WORD,
- FIND,
- HIDDEN,
- EXIT])
+TIB_CFA = defConst("TIB", TIB)
+NUMTIB, NUMTIB_CFA = defNewVar("#TIB", 0)
+TOIN, TOIN_CFA = defNewVar(">IN", 0)
-COLON = defWord(":",
- [WORD,
- CREATE,
- LIT, DOCOL, COMMA,
- LATEST_CFA, FETCH, HIDDEN,
- RBRAC,
+QUERY = defWord("QUERY",
+ [TIB_CFA, LIT, 160, EXPECT,
+ SPAN_CFA, FETCH, NUMTIB_CFA, STORE,
+ LIT, 0, TOIN_CFA, STORE,
EXIT])
-SEMICOLON = defWord(";",
- [LIT, EXIT, COMMA,
- LATEST_CFA, FETCH, HIDDEN,
- LBRAC,
- EXIT], flags=F_IMMED)
+WORD = defPrimWord("WORD", () -> begin
+ delim = popPS()
-IMMEDIATE = defPrimWord("IMMEDIATE", () -> begin
- lenAndFlagsAddr = mem[LATEST] + 1
- mem[lenAndFlagsAddr] = mem[lenAndFlagsAddr] $ F_IMMED
- return NEXT
-end, flags=F_IMMED)
+ # Chew up initial occurrences of delim
+ while (mem[TOIN]<mem[NUMTIB] && mem[TIB+mem[TOIN]] == delim)
+ mem[TOIN] += 1
+ end
-TICK = defWord("'",
- [WORD, FIND, TOCFA, EXIT])
+ countAddr = mem[HERE]
+ addr = mem[HERE]+1
-BTICK = defWord("[']",
- [FROMR, DUP, INCR, TOR, FETCH, EXIT])
+ # 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
-# Strings
+ count += 1
+ addr += 1
+ end
-LITSTRING = defPrimWord("LITSTRING", () -> begin
- len = mem[reg.IP]
- reg.IP += 1
- pushPS(reg.IP)
- pushPS(len)
- reg.IP += len
+ # Record count
+ mem[countAddr] = count
+ pushPS(countAddr)
return NEXT
end)
-TELL = defPrimWord("TELL", () -> begin
- len = popPS()
- addr = popPS()
- str = getString(addr, len)
- print(str)
- return NEXT
-end)
+PARSE = defPrimWord("PARSE", () -> begin
+ delim = popPS()
-# Outer interpreter
+ # Chew up initial occurrences of delim
+ addr = mem[HERE]
-EXECUTE = defPrimWord("EXECUTE", () -> begin
- reg.W = popPS()
- return mem[reg.W]
-end)
+ # Start reading input stream
+ count = 0
+ while (mem[TOIN]<mem[NUMTIB])
+ mem[addr] = mem[TIB+mem[TOIN]]
+ mem[TOIN] += 1
-type ParseError <: Exception
- wordName::ASCIIString
-end
-Base.showerror(io::IO, ex::ParseError) = print(io, "Parse error at word: '$(ex.wordName)'.")
+ if (mem[addr] == delim)
+ break
+ end
-DEBUG, DEBUG_CFA = defNewVar("DEBUG", 0)
+ count += 1
+ addr += 1
+ end
-INTERPRET = defPrimWord("INTERPRET", () -> begin
+ pushPS(addr)
+ pushPS(count)
- callPrim(mem[WORD])
+ return NEXT
+end)
- wordName = getString(mem[reg.PSP-1], mem[reg.PSP])
- if mem[DEBUG] != 0
- println("... ", replace(replace(wordName, "\004", "EOF"), "\n", "\\n"), " ...")
- end
+BYE = defPrimWord("BYE", () -> begin
+ println("Bye!")
+ return 0
+end)
- callPrim(mem[TWODUP])
- callPrim(mem[FIND])
+STATE, STATE_CFA = defNewVar("STATE", 0)
- wordAddr = mem[reg.PSP]
+INTERPRET = defWord("INTERPRET",
+ [LIT, 32, WORD, # Read next space-delimited word
- if wordAddr>0
- # Word in dictionary
+ DUP, FETCH, ZE, ZBRANCH, 3,
+ DROP, EXIT, # Exit if TIB is exhausted
- isImmediate = (mem[wordAddr+1] & F_IMMED) != 0
- callPrim(mem[TOCFA])
+ STATE_CFA, FETCH, ZBRANCH, 31,
+ # Compiling
+ DUP, FIND, QDUP, ZBRANCH, 19,
- callPrim(mem[NROT]) # get rid of extra copy of word string details
- popPS()
- popPS()
+ # Found word.
+ SWAP, DROP,
+ DUP, TOCFA, SWAP, INCR, FETCH, LIT, F_IMMED, AND, ZBRANCH, 4,
+ # Immediate: Execute!
+ EXECUTE, BRANCH, -33,
- if mem[STATE] == 0 || isImmediate
- # Execute!
- return callPrim(mem[EXECUTE])
- else
- # Append CFA to dictionary
- callPrim(mem[COMMA])
- end
- else
- # Not in dictionary, assume number
+ # Not immediate: Compile!
+ COMMA, BRANCH, -36,
- popPS()
+ # No word found, parse number
+ NUMBER, BTICK, LIT, COMMA, COMMA, BRANCH, -43,
+
+ # Interpreting
+ DUP, FIND, QDUP, ZBRANCH, 7,
- callPrim(mem[NUMBER])
+ # Found word. Execute!
+ SWAP, DROP, TOCFA, EXECUTE, BRANCH, -54,
- if popPS() != 0
- throw(ParseError(wordName))
- end
+ # No word found, parse number and leave on stack
+ NUMBER, BRANCH, -57,
+ EXIT]
+)
- if mem[STATE] == 0
- # Number already on stack!
- else
- # Append literal to dictionary
- pushPS(LIT)
- callPrim(mem[COMMA])
- callPrim(mem[COMMA])
- end
+PROMPT = defPrimWord("PROMPT", () -> begin
+ if (mem[STATE] == 0 && currentSource() == STDIN)
+ println(" ok")
end
return NEXT
end)
QUIT = defWord("QUIT",
- [RSP0_CFA, RSPSTORE,
- INTERPRET,
- BRANCH,-2])
-
-BYE = defPrimWord("BYE", () -> begin
- return 0
-end)
-
-PROMPT = defPrimWord("PROMPT", () -> begin
- println(" ok")
-end)
+ [LIT, 0, STATE_CFA, STORE,
+ LIT, 0, NUMTIB_CFA, STORE,
+ RSP0_CFA, RSPSTORE,
+ QUERY,
+ INTERPRET, PROMPT,
+ BRANCH,-4])
-NL = defPrimWord("\n", () -> begin
- if mem[STATE] == 0 && currentSource() == STDIN
- callPrim(mem[PROMPT])
- end
- return NEXT
-end, flags=F_IMMED)
+ABORT = defWord("ABORT",
+ [PSP0_CFA, PSPSTORE, QUIT])
INCLUDE = defPrimWord("INCLUDE", () -> begin
+ pushPS(32)
callPrim(mem[WORD])
- wordLen = popPS()
- wordAddr = popPS()
+ wordAddr = popPS()+1
+ wordLen = mem[wordAddr-1]
word = getString(wordAddr, wordLen)
push!(sources, open(word, "r"))
return NEXT
end)
-EOF_WORD = defPrimWord("\x04", () -> begin
- if currentSource() != STDIN
- close(currentSource())
- end
+# Compilation
- pop!(sources)
+HEADER = defPrimWord("HEADER", () -> begin
+ wordAddr = popPS()+1
+ wordLen = mem[wordAddr-1]
+ word = getString(wordAddr, wordLen)
- if length(sources)>0
- if currentSource() == STDIN
- callPrim(mem[PROMPT])
- end
+ createHeader(word, 0)
- return NEXT
- else
- return 0
- end
-end, flags=F_IMMED)
+ return NEXT
+end)
-# Odds and Ends
+LBRAC = defPrimWord("[", () -> begin
+ mem[STATE] = 0
+ return NEXT
+end, flags=F_IMMED)
-CHAR = defPrimWord("CHAR", () -> begin
- callPrim(mem[WORD])
- wordLen = popPS()
- wordAddr = popPS()
- word = getString(wordAddr, wordLen)
- pushPS(Int64(word[1]))
+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 = Pkg.dir("forth/src/lib.4th")
end
-
-#### VM loop ####
function run(;initialize=true)
# Begin with STDIN as source
push!(sources, STDIN)
jmp = NEXT
while jmp != 0
try
- if mem[DEBUG] != 0
- println("Evaluating prim ", jmp," ", primNames[-jmp])
- end
-
+ #println("Entering prim $(getPrimName(jmp))")
jmp = callPrim(jmp)
catch ex
close(pop!(sources))
end
- mem[STATE] = 0
- mem[NUMTIB] = 0
- reg.PSP = mem[PSP0]
- reg.RSP = mem[RSP0]
- reg.IP = QUIT + 1
+ # QUIT
+ reg.IP = ABORT + 1
jmp = NEXT
end
end
end
function printPS()
- count = reg.PSP - mem[PSP0]
+ count = reg.PSP - PSP0
if count > 0
print("<$count>")
- for i in (mem[PSP0]+1):reg.PSP
+ for i in (PSP0+1):reg.PSP
print(" $(mem[i])")
end
println()
end
function printRS()
- count = reg.RSP - mem[RSP0]
+ count = reg.RSP - RSP0
if count > 0
print("<$count>")
- for i in (mem[RSP0]+1):reg.RSP
+ for i in (RSP0+1):reg.RSP
print(" $(mem[i])")
end
println()
The Lambda Lab / projects / forth.jl.git / blobdiff