module forth
-# VM memory size
-size_memory = 640*1024
+# VM mem size
+size_mem = 640*1024
# Buffer sizes
-size_RS = 1024 # Return stack size
-size_PS = 1024 # Parameter stack size
-size_TIB = 4096 # Terminal input buffer size
+size_RS = 1024 # Return stack size
+size_PS = 1024 # Parameter stack size
+size_TIB = 1096 # Terminal input buffer size
-# VM registers
-RSP = 0 # Return stack pointer
-PSP =0 # Parameter/data stack pointer
-IP = 0 # Instruction pointer
-W = 0 # Working register
-X = 0 # Extra register
-
-RSP0 = 1
-PSP0 = RSP0 + size_RS
-here = PSP0 + size_PS + size_TIB # location of bottom of dictionary
-latest = 0 # no previous definition
-
-# The following array constitutes the memory of the VM. It has the following geography:
+# The mem array constitutes the memory of the VM. It has the following geography:
#
-# memory = +-----------------------+
-# | Return Stack |
-# +-----------------------+
-# | Parameter Stack |
-# +-----------------------+
-# | Terminal Input Buffer |
-# +-----------------------+
-# | Dictionary |
-# +-----------------------+
+# 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.
# blocks, which are represented as anonymous functions, appear the negative index
# into the primitives array which contains only these functions.
-memory = Array{Int64,1}(size_memory)
+mem = Array{Int64,1}(size_mem)
primitives = Array{Function,1}()
+# Built-in variables
+
+nextVarAddr = 1
+RSP0 = nextVarAddr; nextVarAddr += 1
+PSP0 = nextVarAddr; nextVarAddr += 1
+HERE = nextVarAddr; nextVarAddr += 1
+LATEST = nextVarAddr; nextVarAddr += 1
-# Stack manipulation functions
+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
+
+DICT = mem[HERE] # Save bottom of dictionary as constant
+
+# VM registers
+type Reg
+ RSP::Int64 # Return stack pointer
+ PSP::Int64 # Parameter/data stack pointer
+ IP::Int64 # Instruction pointer
+ W::Int64 # Working register
+ X::Int64 # Extra register
+end
+reg = Reg(mem[RSP0], mem[PSP0], 0, 0, 0)
+
+# Stack manipulation
+
+type StackUnderflow <: Exception end
+
+getRSDepth() = reg.RSP - mem[RSP0]
+getPSDepth() = reg.PSP - mem[PSP0]
+
+function ensurePSDepth(depth::Int64)
+ if getPSDepth()<depth
+ throw(StackUnderflow())
+ end
+end
+
+function ensureRSDepth(depth::Int64)
+ if getRSDepth()<depth
+ throw(StackUnderflow())
+ end
+end
function pushRS(val::Int64)
- global RSP
- memory[RSP+=1] = val
+ mem[reg.RSP+=1] = val
end
function popRS()
- global RSP
- val = memory[RSP]
- RSP -= 1
+ ensureRSDepth(1)
+
+ val = mem[reg.RSP]
+ reg.RSP -= 1
return val
end
function pushPS(val::Int64)
- global PSP
- memory[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 and calling functions
-function defPrim(name::AbstractString, f::Function)
- global latest, here
+function createHeader(name::AbstractString, flags::Int64)
+ mem[mem[HERE]] = mem[LATEST]
+ mem[LATEST] = mem[HERE]
+ mem[HERE] += 1
- memory[here] = latest
- latest = here
- here += 1
+ mem[mem[HERE]] = length(name) | flags; mem[HERE] += 1
+ mem[mem[HERE]:(mem[HERE]+length(name)-1)] = [Int(c) for c in name]; mem[HERE] += length(name)
+end
- memory[here] = length(name); here += 1
- memory[here:(here+length(name)-1)] = [Int(c) for c in name]; here += length(name)
+function defPrim(name::AbstractString, f::Function; flags::Int64=0)
+ createHeader(name, flags)
+ codeWordAddr = mem[HERE]
push!(primitives, f)
- memory[here] = -length(primitives)
- here += 1
+ mem[codeWordAddr] = -length(primitives)
+ mem[HERE] += 1
- return -length(primitives)
+ return codeWordAddr
end
callPrim(addr::Int64) = primitives[-addr]()
-function defVar(name::AbstractString, val::Int64)
- global latest, here
+function defExistingVar(name::AbstractString, varAddr::Int64; flags::Int64=0)
+ defPrim(name, eval(:(() -> begin
+ pushPS($(varAddr))
+ return mem[NEXT]
+ end)))
+end
+
+function defNewVar(name::AbstractString, initial::Int64; flags::Int64=0)
+ createHeader(name, flags)
+
+ varAddr = mem[HERE] + 1
+ push!(primitives, eval(:(() -> begin
+ pushPS($(varAddr))
+ return mem[NEXT]
+ end)))
+ mem[mem[HERE]] = -length(primitives); mem[HERE] += 1
- memory[here] = latest
- latest = here
- here += 1
+ mem[mem[HERE]] = initial; mem[HERE] += 1
- memory[here] = length(name); here += 1
- memory[here:(here+length(name)-1)] = [Int(c) for c in name]; here += length(name)
+ return varAddr
+end
+
+function defConst(name::AbstractString, val::Int64; flags::Int64=0)
+ defPrim(name, eval(:(() -> begin
+ pushPS($(val))
+ return mem[NEXT]
+ end)))
+
+ return val
+end
- push!(primitives, () -> begin
+function defWord(name::AbstractString, wordAddrs::Array{Int64,1}; flags::Int64=0)
+ createHeader(name, flags)
- end)
+ addr = mem[HERE]
+ mem[mem[HERE]] = mem[DOCOL]
+ mem[HERE] += 1
- pushPS($var)
- jmp = NEXT
+ for wordAddr in wordAddrs
+ mem[mem[HERE]] = wordAddr
+ mem[HERE] += 1
+ end
+
+ return addr
end
-# Threading Primitives
+# Threading Primitives (inner interpreter)
NEXT = defPrim("NEXT", () -> begin
- W = memory[IP]
- IP += 1
- X = memory[W]
- return X
+ reg.W = mem[reg.IP]
+ reg.IP += 1
+ return mem[reg.W]
end)
DOCOL = defPrim("DOCOL", () -> begin
- pushRS(IP)
- IP = W + 1
- return NEXT
+ pushRS(reg.IP)
+ reg.IP = reg.W + 1
+ return mem[NEXT]
end)
EXIT = defPrim("EXIT", () -> begin
- IP = popRS()
- return NEXT
+ reg.IP = popRS()
+ return mem[NEXT]
end)
-
# Basic forth primitives
DROP = defPrim("DROP", () -> begin
popPS()
- return NEXT
+ return mem[NEXT]
end)
SWAP = defPrim("SWAP", () -> begin
- PS[PSP], PS[PSP-1] = PS[PSP-1], PS[PS]
- return NEXT
+ a = popPS()
+ b = popPS()
+ pushPS(a)
+ pushPS(b)
+ return mem[NEXT]
end)
DUP = defPrim("DUP", () -> begin
- pushPS(PS[PSP])
- return NEXT
+ pushPS(mem[reg.PSP])
+ return mem[NEXT]
+end)
+
+OVER = defPrim("OVER", () -> begin
+ ensurePSDepth(2)
+ pushPS(mem[reg.PSP-1])
+ return mem[NEXT]
+end)
+
+ROT = defPrim("ROT", () -> begin
+ a = popPS()
+ b = popPS()
+ c = popPS()
+ pushPS(a)
+ pushPS(c)
+ pushPS(b)
+ return mem[NEXT]
+end)
+
+NROT = defPrim("-ROT", () -> begin
+ a = popPS()
+ b = popPS()
+ c = popPS()
+ pushPS(b)
+ pushPS(a)
+ pushPS(c)
+ return mem[NEXT]
+end)
+
+TWODROP = defPrim("2DROP", () -> begin
+ popPS()
+ popPS()
+ return mem[NEXT]
+end)
+
+TWODUP = defPrim("2DUP", () -> begin
+ ensurePSDepth(2)
+ a = mem[reg.PSP-1]
+ b = mem[reg.PSP]
+ pushPS(a)
+ pushPS(b)
+ return mem[NEXT]
+end)
+
+TWOSWAP = defPrim("2SWAP", () -> begin
+ a = popPS()
+ b = popPS()
+ c = popPS()
+ d = popPS()
+ pushPS(b)
+ pushPS(a)
+ pushPS(c)
+ pushPS(d)
+ return mem[NEXT]
+end)
+
+QDUP = defPrim("?DUP", () -> begin
+ ensurePSDepth(1)
+ val = mem[reg.PSP]
+ if val != 0
+ pushPS(val)
+ end
+ return mem[NEXT]
+end)
+
+INCR = defPrim("1+", () -> begin
+ ensurePSDepth(1)
+ mem[reg.PSP] += 1
+ return mem[NEXT]
+end)
+
+DECR = defPrim("1-", () -> begin
+ ensurePSDepth(1)
+ mem[reg.PSP] -= 1
+ return mem[NEXT]
+end)
+
+INCR2 = defPrim("2+", () -> begin
+ ensurePSDepth(1)
+ mem[reg.PSP] += 2
+ return mem[NEXT]
+end)
+
+DECR2 = defPrim("2-", () -> begin
+ ensurePSDepth(1)
+ mem[reg.PSP] -= 2
+ return mem[NEXT]
+end)
+
+ADD = defPrim("+", () -> begin
+ b = popPS()
+ a = popPS()
+ pushPS(a+b)
+ return mem[NEXT]
+end)
+
+SUB = defPrim("-", () -> begin
+ b = popPS()
+ a = popPS()
+ pushPS(a-b)
+ return mem[NEXT]
+end)
+
+MUL = defPrim("*", () -> begin
+ b = popPS()
+ a = popPS()
+ pushPS(a*b)
+ return mem[NEXT]
+end)
+
+DIVMOD = defPrim("/MOD", () -> begin
+ b = popPS()
+ a = popPS()
+ q,r = divrem(a,b)
+ pushPS(r)
+ pushPS(q)
+ return mem[NEXT]
+end)
+
+EQU = defPrim("=", () -> begin
+ b = popPS()
+ a = popPS()
+ pushPS(a==b ? -1 : 0)
+ return mem[NEXT]
+end)
+
+NEQU = defPrim("<>", () -> begin
+ b = popPS()
+ a = popPS()
+ pushPS(a!=b ? -1 : 0)
+ return mem[NEXT]
+end)
+
+LT = defPrim("<", () -> begin
+ b = popPS()
+ a = popPS()
+ pushPS(a<b ? -1 : 0)
+ return mem[NEXT]
+end)
+
+GT = defPrim(">", () -> begin
+ b = popPS()
+ a = popPS()
+ pushPS(a>b ? -1 : 0)
+ return mem[NEXT]
+end)
+
+LE = defPrim("<=", () -> begin
+ b = popPS()
+ a = popPS()
+ pushPS(a<=b ? -1 : 0)
+ return mem[NEXT]
+end)
+
+GE = defPrim(">=", () -> begin
+ b = popPS()
+ a = popPS()
+ pushPS(a>=b ? -1 : 0)
+ return mem[NEXT]
+end)
+
+ZEQU = defPrim("0=", () -> begin
+ pushPS(popPS() == 0 ? -1 : 0)
+ return mem[NEXT]
+end)
+
+ZNEQU = defPrim("0<>", () -> begin
+ pushPS(popPS() != 0 ? -1 : 0)
+ return mem[NEXT]
+end)
+
+ZLT = defPrim("0<", () -> begin
+ pushPS(popPS() < 0 ? -1 : 0)
+ return mem[NEXT]
+end)
+
+ZGT = defPrim("0>", () -> begin
+ pushPS(popPS() > 0 ? -1 : 0)
+ return mem[NEXT]
+end)
+
+ZLE = defPrim("0<=", () -> begin
+ pushPS(popPS() <= 0 ? -1 : 0)
+ return mem[NEXT]
end)
+ZGE = defPrim("0>=", () -> begin
+ pushPS(popPS() >= 0 ? -1 : 0)
+ return mem[NEXT]
+end)
+
+AND = defPrim("AND", () -> begin
+ b = popPS()
+ a = popPS()
+ pushPS(a & b)
+ return mem[NEXT]
+end)
+
+OR = defPrim("OR", () -> begin
+ b = popPS()
+ a = popPS()
+ pushPS(a | b)
+ return mem[NEXT]
+end)
+
+XOR = defPrim("XOR", () -> begin
+ b = popPS()
+ a = popPS()
+ pushPS(a $ b)
+ return mem[NEXT]
+end)
+
+INVERT = defPrim("INVERT", () -> begin
+ pushPS(~popPS())
+ return mem[NEXT]
+end)
+
+# Literals
+
LIT = defPrim("LIT", () -> begin
- pushPS(memory[IP])
- IP += 1
- return NEXT
+ pushPS(mem[reg.IP])
+ reg.IP += 1
+ return mem[NEXT]
end)
# Memory primitives
-STORE = defPrim("!", quote
+STORE = defPrim("!", () -> begin
addr = popPS()
dat = popPS()
- memory[addr] = dat
- return NEXT
+ mem[addr] = dat
+ return mem[NEXT]
end)
-FETCH = defPrim("@", quote
+FETCH = defPrim("@", () -> begin
addr = popPS()
- pushPS(memory[addr])
- return NEXT
+ pushPS(mem[addr])
+ return mem[NEXT]
end)
-ADDSTORE = defPrim("+!", quote
+ADDSTORE = defPrim("+!", () -> begin
addr = popPS()
toAdd = popPS()
- memory[addr] += toAdd
- return NEXT
+ mem[addr] += toAdd
+ return mem[NEXT]
end)
-SUBSTORE = defPrim("-!", quote
+SUBSTORE = defPrim("-!", () -> begin
addr = popPS()
toSub = popPS()
- memory[addr] -= toSub
- return NEXT
+ mem[addr] -= toSub
+ return mem[NEXT]
end)
# Built-in variables
-defVar("STATE", :state)
-defVar("HERE", :here)
-defVar("LATEST", :latest)
-defVar("BASE", :base)
+defExistingVar("HERE", HERE)
+defExistingVar("LATEST", LATEST)
+defExistingVar("PSP0", PSP0)
+defExistingVar("RSP0", RSP0)
+STATE = defNewVar("STATE", 0)
+BASE = 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 = defPrim(">R", () -> begin
pushRS(popPS())
- return NEXT
+ return mem[NEXT]
end)
FROMR = defPrim("R>", () -> begin
pushPS(popRS())
- return NEXT
+ return mem[NEXT]
end)
RSPFETCH = defPrim("RSP@", () -> begin
- pushPS(RSP)
- return NEXT
+ pushPS(reg.RSP)
+ return mem[NEXT]
end)
RSPSTORE = defPrim("RSP!", () -> begin
RSP = popPS()
- return NEXT
+ return mem[NEXT]
end)
RDROP = defPrim("RDROP", () -> begin
popRS()
- return NEXT
+ return mem[NEXT]
end)
# Parameter Stack
PSPFETCH = defPrim("PSP@", () -> begin
- pushPS(PSP)
- return NEXT
+ pushPS(reg.PSP)
+ return mem[NEXT]
end)
PSPSTORE = defPrim("PSP!", () -> begin
PSP = popPS()
- return NEXT
+ return mem[NEXT]
end)
# I/O
-defConst("TIB", tib)
-defVar("#TIB", :numtib)
-defVar(">IN", :toin)
+defConst("TIB", TIB)
+NUMTIB = defNewVar("#TIB", 0)
+TOIN = defNewVar(">IN", 0)
KEY = defPrim("KEY", () -> begin
- if toin >= numtib
-
+ if mem[TOIN] >= mem[NUMTIB]
+ mem[TOIN] = 0
+ line = readline()
+ mem[NUMTIB] = length(line)
+ mem[TIB:(TIB+mem[NUMTIB]-1)] = [Int64(c) for c in collect(line)]
end
- return NEXT
+ pushPS(mem[TIB + mem[TOIN]])
+ mem[TOIN] += 1
+
+ return mem[NEXT]
end)
EMIT = defPrim("EMIT", () -> begin
-
- return NEXT
+ print(Char(popPS()))
+ return mem[NEXT]
end)
WORD = defPrim("WORD", () -> begin
+
+ c = -1
+
+ 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'
+ skip_to_end = false
+ end
+ continue
+ end
+
+ if c == ' ' || c == '\t'
+ continue
+ end
+
+ break
+ end
- return NEXT
+ wordAddr = mem[HERE]
+ offset = 0
+
+ while true
+ mem[wordAddr + offset] = Int64(c)
+ offset += 1
+
+ callPrim(mem[KEY])
+ c = Char(popPS())
+
+ if c == ' ' || c == '\t' || c == '\n'
+ break
+ end
+ end
+
+ wordLen = offset
+
+ pushPS(wordAddr)
+ pushPS(wordLen)
+
+ return mem[NEXT]
end)
NUMBER = defPrim("NUMBER", () -> begin
- return NEXT
+ wordLen = popPS()
+ wordAddr = popPS()
+
+ s = ASCIIString([Char(c) for c in mem[wordAddr:(wordAddr+wordLen-1)]])
+
+ try
+ pushPS(parse(Int64, s, mem[BASE]))
+ pushPS(0)
+ catch
+ pushPS(1) # Error indication
+ end
+
+ return mem[NEXT]
+end)
+
+# Dictionary searches
+
+FIND = defPrim("FIND", () -> begin
+
+ wordLen = popPS()
+ wordAddr = popPS()
+ word = ASCIIString([Char(c) for c in mem[wordAddr:(wordAddr+wordLen-1)]])
+
+ latest = mem[LATEST]
+
+ while latest>0
+ lenAndFlags = mem[latest+1]
+ len = lenAndFlags & F_LENMASK
+ hidden = (lenAndFlags & F_HIDDEN) == F_HIDDEN
+
+ if hidden || len != wordLen
+ latest = mem[latest]
+ continue
+ end
+
+ thisAddr = latest+2
+ thisWord = ASCIIString([Char(c) for c in mem[thisAddr:(thisAddr+len-1)]])
+
+ if thisWord == word
+ break
+ end
+ end
+
+ pushPS(latest)
+
+ return mem[NEXT]
end)
+TOCFA = defPrim(">CFA", () -> begin
+
+ addr = popPS()
+ lenAndFlags = mem[addr+1]
+ len = lenAndFlags & F_LENMASK
+
+ pushPS(addr + 2 + len)
+
+ return mem[NEXT]
+end)
+
+TODFA = defWord(">DFA", [TOCFA, INCR, EXIT])
+
+# Compilation
+
+CREATE = defPrim("CREATE", () -> begin
+
+ wordLen = popPS()
+ wordAddr = popPS()
+ word = ASCIIString([Char(c) for c in mem[wordAddr:(wordAddr+wordLen-1)]])
+
+ mem[mem[HERE]] = mem[LATEST]; mem[HERE] += 1
+ mem[LATEST] = mem[HERE]
+ mem[mem[HERE]] = wordLen; mem[HERE] += 1
+
+ mem[mem[HERE]:(mem[HERE]+wordLen-1)] = collect(Int64, word)
+ mem[HERE] += wordLen
+
+ return mem[NEXT]
+end)
+
+COMMA = defPrim(",", () -> begin
+ mem[mem[HERE]] = popPS()
+ mem[HERE] += 1
+
+ return mem[NEXT]
+end)
+
+LBRAC = defPrim("[", () -> begin
+ mem[STATE] = 0
+ return mem[NEXT]
+end, flags=F_IMMED)
+
+RBRAC = defPrim("]", () -> begin
+ mem[STATE] = 1
+ return mem[NEXT]
+end, flags=F_IMMED)
+
+HIDDEN = defPrim("HIDDEN", () -> begin
+ addr = popPS() + 1
+ mem[addr] = mem[addr] $ F_HIDDEN
+ return mem[NEXT]
+end)
+
+HIDE = defWord("HIDE",
+ [WORD,
+ FIND,
+ HIDDEN,
+ EXIT])
+
+COLON = defWord(":",
+ [WORD,
+ CREATE,
+ LIT, DOCOL, COMMA,
+ LATEST, FETCH, HIDDEN,
+ RBRAC,
+ EXIT])
+
+SEMICOLON = defWord(";",
+ [LIT, EXIT, COMMA,
+ LATEST, FETCH, HIDDEN,
+ LBRAC,
+ EXIT], flags=F_IMMED)
+
+IMMEDIATE = defPrim("IMMEDIATE", () -> begin
+ lenAndFlagsAddr = mem[LATEST] + 1
+ mem[lenAndFlagsAddr] = mem[lenAndFlagsAddr] $ F_IMMED
+ return mem[NEXT]
+end, flags=F_IMMED)
+
+TICK = defWord("'", [WORD, FIND, TOCFA, EXIT])
+
+# Branching
+
+BRANCH = defPrim("BRANCH", () -> begin
+ reg.IP += mem[reg.IP]
+ return mem[NEXT]
+end)
+
+ZBRANCH = defPrim("0BRANCH", () -> begin
+ if (popPS() == 0)
+ reg.IP += mem[reg.IP]
+ else
+ reg.IP += 1
+ end
+
+ return mem[NEXT]
+end)
+
+# Strings
+
#### VM loop ####
function runVM()
- jmp = NEXT
+ jmp = mem[NEXT]
while (jmp = callPrim(jmp)) != 0 end
end
+# Debugging tools
+
+function dump(startAddr::Int64; count::Int64 = 100, cellsPerLine::Int64 = 10)
+ chars = Array{Char,1}(cellsPerLine)
+
+ for i in 0:(count-1)
+ addr = startAddr + i
+ if i%cellsPerLine == 0
+ print("$addr:")
+ end
+
+ print("\t$(mem[addr]) ")
+
+ if (mem[addr]>=32 && mem[addr]<128)
+ chars[i%cellsPerLine + 1] = Char(mem[addr])
+ else
+ chars[i%cellsPerLine + 1] = '.'
+ end
+
+ if i%cellsPerLine == cellsPerLine-1
+ println(string("\t", ASCIIString(chars)))
+ end
+ end
+end
+
+function printPS()
+ count = reg.PSP - mem[PSP0]
+
+ if count > 0
+ print("<$count>")
+ for i in (mem[PSP0]+1):reg.PSP
+ print(" $(mem[i])")
+ end
+ println()
+ else
+ println("Parameter stack empty")
+ end
+end
+
+function printRS()
+ count = reg.RSP - mem[RSP0]
+
+ if count > 0
+ print("<$count>")
+ for i in (mem[RSP0]+1):reg.RSP
+ print(" $(mem[i])")
+ end
+ println()
+ else
+ println("Return stack empty")
+ end
+end
+
end
The Lambda Lab / projects / forth.jl.git / blobdiff