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:
#
callPrim(addr::Int64) = primitives[-addr]()
-# Word creation
+# Word creation functions
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)
+
+ mem[mem[HERE]] = DOCON; mem[HERE] += 1
+ mem[mem[HERE]] = val; mem[HERE] += 1
return val
end
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 = defExistingVar("PSP0", PSP0)
+RSP0_CFA = defExistingVar("RSP0", RSP0)
+
+defConst("DOCOL", DOCOL)
+defConst("DOCON", DOCON)
+defConst("DOVAR", DOVAR)
+
+defConst("DICT", DICT)
+defConst("MEMSIZE", size_mem)
+
+F_IMMED = defConst("F_IMMED", 128)
+F_HIDDEN = defConst("F_HIDDEN", 256)
+F_LENMASK = defConst("F_LENMASK", 127)
+
# Basic forth primitives
DROP = defPrimWord("DROP", () -> begin
d = popPS()
pushPS(b)
pushPS(a)
- pushPS(c)
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)
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
return NEXT
end)
+BASE, BASE_CFA = defNewVar("BASE", 10)
NUMBER = defPrimWord("NUMBER", () -> begin
wordLen = popPS()
# Compilation
-CREATE = defPrimWord("CREATE", () -> begin
+STATE, STATE_CFA = defNewVar("STATE", 0)
+
+HEADER = defPrimWord("HEADER", () -> begin
wordLen = popPS()
wordAddr = popPS()
HIDDEN,
EXIT])
+CREATE = defWord("CREATE",
+ [WORD,
+ HEADER,
+ LIT, DOVAR, COMMA, EXIT]);
+
COLON = defWord(":",
[WORD,
- CREATE,
+ HEADER,
LIT, DOCOL, COMMA,
LATEST_CFA, FETCH, HIDDEN,
RBRAC,
end, flags=F_IMMED)
TICK = defWord("'",
- [STATE_CFA, FETCH, ZBRANCH, 7,
- FROMR, DUP, INCR, TOR, FETCH, EXIT,
- WORD, FIND, TOCFA, EXIT])
+ [WORD, FIND, TOCFA, EXIT])
+
+BTICK = defWord("[']",
+ [FROMR, DUP, INCR, TOR, FETCH, EXIT])
+
# Strings
mem[STATE] = 0
mem[NUMTIB] = 0
+ reg.PSP = mem[PSP0]
+ reg.RSP = mem[RSP0]
reg.IP = QUIT + 1
jmp = NEXT
end