PSP::Int64 # Parameter/data stack pointer
IP::Int64 # Instruction pointer
W::Int64 # Working register
-
- source::Any # Input stream in use
end
-reg = Reg(mem[RSP0], mem[PSP0], 0, 0, STDIN)
+reg = Reg(mem[RSP0], mem[PSP0], 0, 0)
# Stack manipulation functions
-type StackUnderflow <: Exception end
+type ParamStackUnderflow <: Exception end
+type ReturnStackUnderflow <: Exception end
+
+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]
function ensurePSDepth(depth::Int64)
if getPSDepth()<depth
- throw(StackUnderflow())
+ throw(ParamStackUnderflow())
end
end
function ensureRSDepth(depth::Int64)
if getRSDepth()<depth
- throw(StackUnderflow())
+ throw(ReturnStackUnderflow())
end
end
a = popPS()
b = popPS()
c = popPS()
+ pushPS(b)
pushPS(a)
pushPS(c)
- pushPS(b)
return NEXT
end)
a = popPS()
b = popPS()
c = popPS()
- pushPS(b)
pushPS(a)
pushPS(c)
+ pushPS(b)
return NEXT
end)
+
TWODROP = defPrimWord("2DROP", () -> begin
popPS()
popPS()
return NEXT
end)
+TWOMUL = defPrimWord("2*", () -> begin
+ pushPS(popPS() << 1)
+ return NEXT
+end)
+
+TWODIV = defPrimWord("2/", () -> begin
+ pushPS(popPS() >> 1)
+ return NEXT
+end)
+
EQU = defPrimWord("=", () -> begin
b = popPS()
a = popPS()
return NEXT
end)
+RFETCH = defPrimWord("R@", () -> begin
+ pushPS(mem[reg.RSP])
+ return NEXT
+end)
+
RSPFETCH = defPrimWord("RSP@", () -> begin
pushPS(reg.RSP)
return NEXT
# I/O
+sources = Array{Any,1}()
+currentSource() = sources[length(sources)]
+
defConst("TIB", TIB)
NUMTIB, NUMTIB_CFA = defNewVar("#TIB", 0)
TOIN, TOIN_CFA = defNewVar(">IN", 0)
if mem[TOIN] >= mem[NUMTIB]
mem[TOIN] = 0
- if !eof(reg.source)
- line = readline(reg.source)
+ if !eof(currentSource())
+ line = readline(currentSource())
mem[NUMTIB] = length(line)
putString(line, TIB)
else
TODFA = defWord(">DFA", [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)
+
# Compilation
CREATE = defPrimWord("CREATE", () -> begin
return NEXT
end, flags=F_IMMED)
-TICK = defWord("'", [WORD, FIND, TOCFA, 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)
+TICK = defWord("'",
+ [STATE_CFA, FETCH, ZBRANCH, 7,
+ FROMR, DUP, INCR, TOR, FETCH, EXIT,
+ WORD, FIND, TOCFA, EXIT])
# Strings
return mem[reg.W]
end)
+type ParseError <: Exception
+ wordName::ASCIIString
+end
+Base.showerror(io::IO, ex::ParseError) = print(io, "Parse error at word: '$(ex.wordName)'.")
+
+DEBUG, DEBUG_CFA = defNewVar("DEBUG", 0)
+
INTERPRET = defPrimWord("INTERPRET", () -> begin
callPrim(mem[WORD])
wordName = getString(mem[reg.PSP-1], mem[reg.PSP])
- #println("... ", replace(replace(wordName, "\004", "EOF"), "\n", "\\n"), " ...")
+ if mem[DEBUG] != 0
+ println("... ", replace(replace(wordName, "\004", "EOF"), "\n", "\\n"), " ...")
+ end
callPrim(mem[TWODUP])
callPrim(mem[FIND])
isImmediate = (mem[wordAddr+1] & F_IMMED) != 0
callPrim(mem[TOCFA])
- callPrim(mem[ROT]) # get rid of extra copy of word string details
+ callPrim(mem[NROT]) # get rid of extra copy of word string details
popPS()
popPS()
if mem[STATE] == 0 || isImmediate
# Execute!
- #println("Executing CFA at $(mem[reg.PSP])")
return callPrim(mem[EXECUTE])
else
# Append CFA to dictionary
callPrim(mem[NUMBER])
if popPS() != 0
- println("Parse error at word: '$wordName'")
- return NEXT
+ throw(ParseError(wordName))
end
if mem[STATE] == 0
return 0
end)
+PROMPT = defPrimWord("PROMPT", () -> begin
+ println(" ok")
+end)
+
NL = defPrimWord("\n", () -> begin
- if mem[STATE] == 0 && reg.source == STDIN
- println(" ok")
+ if mem[STATE] == 0 && currentSource() == STDIN
+ callPrim(mem[PROMPT])
end
return NEXT
end, flags=F_IMMED)
INCLUDE = defPrimWord("INCLUDE", () -> begin
-
callPrim(mem[WORD])
wordLen = popPS()
wordAddr = popPS()
word = getString(wordAddr, wordLen)
- reg.source = open(word, "r")
+ push!(sources, open(word, "r"))
# Clear input buffer
mem[NUMTIB] = 0
end)
EOF_WORD = defPrimWord("\x04", () -> begin
- if reg.source == STDIN
- return 0
- else
- close(reg.source)
- reg.source = STDIN
+ if currentSource() != STDIN
+ close(currentSource())
+ end
+
+ pop!(sources)
+
+ if length(sources)>0
+ if currentSource() == STDIN
+ callPrim(mem[PROMPT])
+ end
+
return NEXT
+ else
+ return 0
end
end, flags=F_IMMED)
return NEXT
end)
+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
+
+
#### VM loop ####
-function run()
+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
jmp = NEXT
while jmp != 0
try
- #println("Evaluating prim $jmp $(primNames[-jmp])")
+ if mem[DEBUG] != 0
+ println("Evaluating prim ", jmp," ", primNames[-jmp])
+ end
+
jmp = callPrim(jmp)
catch ex
- if isa(ex, StackUnderflow)
- println("Stack underflow!")
+ showerror(STDOUT, ex)
+ println()
- mem[NUMTIB] = 0
- reg.IP = QUIT + 1
- jmp = NEXT
+ while !isempty(sources) && currentSource() != STDIN
+ close(pop!(sources))
end
+
+ mem[STATE] = 0
+ mem[NUMTIB] = 0
+ reg.IP = QUIT + 1
+ jmp = NEXT
end
end
end
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