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A minimal Forth compiler in ANSI C
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lbForth.c
/*******************************************************************************
*
* A minimal Forth compiler in C
* By Leif Bruder <leifbruder@gmail.com> http://defineanswer42.wordpress.com
* Release 2014-04-04
*
* Based on Richard W.M. Jones' excellent Jonesforth sources/tutorial
*
* PUBLIC DOMAIN
*
* I, the copyright holder of this work, hereby release it into the public
* domain. This applies worldwide. In case this is not legally possible, I grant
* any entity the right to use this work for any purpose, without any conditions,
* unless such conditions are required by law.
*
*******************************************************************************/
/* Only a single include here; I'll define everything on the fly to keep
* dependencies as low as possible. In this file, the only C standard functions
* used are getchar, putchar and the EOF value. */
#include <stdio.h>
/* Base cell data types. Use short/long on most systems for 16 bit cells. */
/* Experiment here if necessary. */
#define CELL_BASE_TYPE int
#define DOUBLE_CELL_BASE_TYPE long
/* Basic memory configuration */
#define MEM_SIZE 65536 /* main memory size in bytes */
#define STACK_SIZE 192 /* cells reserved for the stack */
#define RSTACK_SIZE 64 /* cells reserved for the return stack */
#define INPUT_LINE_SIZE 32 /* bytes reserved for the WORD buffer */
/******************************************************************************/
/* Our basic data types */
typedef CELL_BASE_TYPE scell;
typedef DOUBLE_CELL_BASE_TYPE dscell;
typedef unsigned CELL_BASE_TYPE cell;
typedef unsigned DOUBLE_CELL_BASE_TYPE dcell;
typedef unsigned char byte;
#define CELL_SIZE sizeof(cell)
#define DCELL_SIZE sizeof(dcell)
/* A few constants that describe the memory layout of this implementation */
#define LATEST_POSITION INPUT_LINE_SIZE
#define HERE_POSITION (LATEST_POSITION + CELL_SIZE)
#define BASE_POSITION (HERE_POSITION + CELL_SIZE)
#define STATE_POSITION (BASE_POSITION + CELL_SIZE)
#define STACK_POSITION (STATE_POSITION + CELL_SIZE)
#define RSTACK_POSITION (STACK_POSITION + STACK_SIZE * CELL_SIZE)
#define HERE_START (RSTACK_POSITION + RSTACK_SIZE * CELL_SIZE)
#define MAX_BUILTIN_ID 71
/* Flags and masks for the dictionary */
#define FLAG_IMMEDIATE 0x80
#define FLAG_HIDDEN 0x40
#define MASK_NAMELENGTH 0x1F
/* This is the main memory to be used by this Forth. There will be no malloc
* in this file. */
byte memory[MEM_SIZE];
/* Pointers to Forth variables stored inside the main memory array */
cell *latest;
cell *here;
cell *base;
cell *state;
cell *sp;
cell *stack;
cell *rsp;
cell *rstack;
/* A few helper variables for the compiler */
int exitReq;
int errorFlag;
cell next;
cell lastIp;
cell quit_address;
cell commandAddress;
cell maxBuiltinAddress;
/* The TIB, stored outside the main memory array for now */
char lineBuffer[128];
int charsInLineBuffer = 0;
int positionInLineBuffer = 0;
/* A basic setup for defining builtins. This Forth uses impossibly low
* adresses as IDs for the builtins so we can define builtins as
* standard C functions. Slower but easier to port. */
#define BUILTIN(id, name, c_name, flags) const int c_name##_id=id; const char* c_name##_name=name; const byte c_name##_flags=flags; void c_name()
#define ADD_BUILTIN(c_name) addBuiltin(c_name##_id, c_name##_name, c_name##_flags, c_name)
typedef void(*builtin)();
builtin builtins[MAX_BUILTIN_ID] = { 0 };
/* This is our initialization script containing all the words we define in
* Forth for convenience. Focus is on simplicity, not speed. Partly copied from
* Jonesforth (see top of file). */
char *initscript_pos;
const char *initScript =
": DECIMAL 10 BASE ! ;\n"
": HEX 16 BASE ! ;\n"
": OCTAL 8 BASE ! ;\n"
": 2DUP OVER OVER ;\n"
": 2DROP DROP DROP ;\n"
": NIP SWAP DROP ;\n"
": 2NIP 2SWAP 2DROP ;\n"
": TUCK SWAP OVER ;\n"
": / /MOD NIP ;\n"
": MOD /MOD DROP ;\n"
": BL 32 ;\n"
": CR 10 EMIT ;\n"
": SPACE BL EMIT ;\n"
": NEGATE 0 SWAP - ;\n"
": DNEGATE 0. 2SWAP D- ;\n"
": CELLS CELL * ;\n"
": ALLOT HERE @ + HERE ! ;\n"
": TRUE -1 ;\n"
": FALSE 0 ;\n"
": 0= 0 = ;\n"
": 0< 0 < ;\n"
": 0> 0 > ;\n"
": <> = 0= ;\n"
": <= > 0= ;\n"
": >= < 0= ;\n"
": 0<= 0 <= ;\n"
": 0>= 0 >= ;\n"
": 1+ 1 + ;\n"
": 1- 1 - ;\n"
": 2+ 2 + ;\n"
": 2- 2 - ;\n"
": 2/ 2 / ;\n"
": 2* 2 * ;\n"
": D2/ 2. D/ ;\n"
": +! DUP @ ROT + SWAP ! ;\n"
": [COMPILE] WORD FIND >CFA , ; IMMEDIATE\n"
": [CHAR] key ' LIT , , ; IMMEDIATE\n"
": RECURSE LATEST @ >CFA , ; IMMEDIATE\n"
": DOCOL 0 ;\n"
": CONSTANT CREATE DOCOL , ' LIT , , ' EXIT , ;\n"
": 2CONSTANT SWAP CREATE DOCOL , ' LIT , , ' LIT , , ' EXIT , ;\n"
": VARIABLE HERE @ CELL ALLOT CREATE DOCOL , ' LIT , , ' EXIT , ;\n" /* TODO: Allot AFTER the code, not before */
": 2VARIABLE HERE @ 2 CELLS ALLOT CREATE DOCOL , ' LIT , , ' EXIT , ;\n" /* TODO: Allot AFTER the code, not before */
": IF ' 0BRANCH , HERE @ 0 , ; IMMEDIATE\n"
": THEN DUP HERE @ SWAP - SWAP ! ; IMMEDIATE\n"
": ELSE ' BRANCH , HERE @ 0 , SWAP DUP HERE @ SWAP - SWAP ! ; IMMEDIATE\n"
": BEGIN HERE @ ; IMMEDIATE\n"
": UNTIL ' 0BRANCH , HERE @ - , ; IMMEDIATE\n"
": AGAIN ' BRANCH , HERE @ - , ; IMMEDIATE\n"
": WHILE ' 0BRANCH , HERE @ 0 , ; IMMEDIATE\n"
": REPEAT ' BRANCH , SWAP HERE @ - , DUP HERE @ SWAP - SWAP ! ; IMMEDIATE\n"
": UNLESS ' 0= , [COMPILE] IF ; IMMEDIATE\n"
": DO HERE @ ' SWAP , ' >R , ' >R , ; IMMEDIATE\n"
": LOOP ' R> , ' R> , ' SWAP , ' 1+ , ' 2DUP , ' = , ' 0BRANCH , HERE @ - , ' 2DROP , ; IMMEDIATE\n"
": +LOOP ' R> , ' R> , ' SWAP , ' ROT , ' + , ' 2DUP , ' <= , ' 0BRANCH , HERE @ - , ' 2DROP , ; IMMEDIATE\n"
": I ' R@ , ; IMMEDIATE\n"
": SPACES DUP 0> IF 0 DO SPACE LOOP ELSE DROP THEN ;\n"
": ABS DUP 0< IF NEGATE THEN ;\n"
": DABS 2DUP 0. D< IF DNEGATE THEN ;\n"
": .DIGIT DUP 9 > IF 55 ELSE 48 THEN + EMIT ;\n"
": .SIGN DUP 0< IF 45 EMIT NEGATE THEN ;\n" /* BUG: 10000000000... will be shown wrong */
": .POS BASE @ /MOD ?DUP IF RECURSE THEN .DIGIT ;\n"
": . .SIGN DUP IF .POS ELSE .DIGIT THEN ;\n"
": COUNTPOS SWAP 1 + SWAP BASE @ / ?DUP IF RECURSE THEN ;\n"
": DIGITS DUP 0< IF 1 ELSE 0 THEN SWAP COUNTPOS ;\n"
": .R OVER DIGITS - SPACES . ;\n"
": . . SPACE ;\n"
": ? @ . ;\n"
": .S DSP@ BEGIN DUP S0@ > WHILE DUP ? CELL - REPEAT DROP ;\n"
": TYPE 0 DO DUP C@ EMIT 1 + LOOP DROP ;\n"
": ALIGN BEGIN HERE @ CELL MOD WHILE 0 C, REPEAT ;\n"
": s\" ' LITSTRING , HERE @ 0 , BEGIN KEY DUP 34 <> WHILE C, REPEAT DROP DUP HERE @ SWAP - CELL - SWAP ! ALIGN ; IMMEDIATE\n"
": .\" [COMPILE] s\" ' TYPE , ; IMMEDIATE\n"
": ( BEGIN KEY [CHAR] ) = UNTIL ; IMMEDIATE\n"
": COUNT DUP 1+ SWAP C@ ;\n"
": MIN 2DUP < IF DROP ELSE NIP THEN ;\n"
": MAX 2DUP > IF DROP ELSE NIP THEN ;\n"
": D0= OR 0= ;\n"
": DMIN 2OVER 2OVER D< IF 2DROP ELSE 2NIP THEN ;\n"
": DMAX 2OVER 2OVER D> IF 2DROP ELSE 2NIP THEN ;\n"
;
/******************************************************************************/
/* The primary data output function. This is the place to change if you want
* to e.g. output data on a microcontroller via a serial interface. */
void putkey(char c)
{
putchar(c);
}
/* The primary data input function. This is where you place the code to e.g.
* read from a serial line. */
int llkey()
{
if (*initscript_pos) return *(initscript_pos++);
return getchar();
}
/* Anything waiting in the keyboard buffer? */
int keyWaiting()
{
return positionInLineBuffer < charsInLineBuffer ? -1 : 0;
}
/* Line buffered character input. We're duplicating the functionality of the
* stdio library here to make the code easier to port to other input sources */
int getkey()
{
int c;
if (keyWaiting())
return lineBuffer[positionInLineBuffer++];
charsInLineBuffer = 0;
while ((c = llkey()) != EOF)
{
if (charsInLineBuffer == sizeof(lineBuffer)) break;
lineBuffer[charsInLineBuffer++] = c;
if (c == '\n') break;
}
positionInLineBuffer = 1;
return lineBuffer[0];
}
/* C string output */
void tell(const char *str)
{
while (*str)
putkey(*str++);
}
/* The basic (data) stack operations */
cell pop()
{
if (*sp == 1)
{
tell("? Stack underflow\n");
errorFlag = 1;
return 0;
}
return stack[--(*sp)];
}
cell tos()
{
if (*sp == 1)
{
tell("? Stack underflow\n");
errorFlag = 1;
return 0;
}
return stack[(*sp)-1];
}
void push(cell data)
{
if (*sp >= STACK_SIZE)
{
tell("? Stack overflow\n");
errorFlag = 1;
return;
}
stack[(*sp)++] = data;
}
dcell dpop()
{
cell tmp[2];
tmp[1] = pop();
tmp[0] = pop();
return *((dcell*)tmp);
}
void dpush(dcell data)
{
cell tmp[2];
*((dcell*)tmp) = data;
push(tmp[0]);
push(tmp[1]);
}
/* The basic return stack operations */
cell rpop()
{
if (*rsp == 1)
{
tell("? RStack underflow\n");
errorFlag = 1;
return 0;
}
return rstack[--(*rsp)];
}
void rpush(cell data)
{
if (*rsp >= RSTACK_SIZE)
{
tell("? RStack overflow\n");
errorFlag = 1;
return;
}
rstack[(*rsp)++] = data;
}
/* Secure memory access */
cell readMem(cell address)
{
if (address > MEM_SIZE)
{
tell("Internal error in readMem: Invalid addres\n");
errorFlag = 1;
return 0;
}
return *((cell*)(memory + address));
}
void writeMem(cell address, cell value)
{
if (address > MEM_SIZE)
{
tell("Internal error in writeMem: Invalid address\n");
errorFlag = 1;
return;
}
*((cell*)(memory + address)) = value;
}
/* Reading a word into the input line buffer */
byte readWord()
{
char *line = (char*)memory;
byte len = 0;
int c;
while ((c = getkey()) != EOF)
{
if (c == ' ') continue;
if (c == '\n') continue;
if (c != '\\') break;
while ((c = getkey()) != EOF)
if (c == '\n')
break;
}
while (c != ' ' && c != '\n' && c != EOF)
{
if (len >= (INPUT_LINE_SIZE - 1))
break;
line[++len] = c;
c = getkey();
}
line[0] = len;
return len;
}
/* toupper() clone so we don't have to pull in ctype.h */
char up(char c)
{
return (c >= 'a' && c <= 'z') ? c - 'a' + 'A' : c;
}
/* Dictionary lookup */
cell findWord(cell address, cell len)
{
cell ret = *latest;
char *name = (char*)&memory[address];
cell i;
int found;
for (ret = *latest; ret; ret = readMem(ret))
{
if ((memory[ret + CELL_SIZE] & MASK_NAMELENGTH) != len) continue;
if (memory[ret + CELL_SIZE] & FLAG_HIDDEN) continue;
found = 1;
for (i = 0; i < len; i++)
{
if (up(memory[ret + i + 1 + CELL_SIZE]) != up(name[i]))
{
found = 0;
break;
}
}
if (found) break;
}
return ret;
}
/* Basic number parsing, base <= 36 only atm */
void parseNumber(byte *word, cell len, dcell *number, cell *notRead, byte *isDouble)
{
int negative = 0;
cell i;
char c;
cell current;
*number = 0;
*isDouble = 0;
if (len == 0)
{
*notRead = 0;
return;
}
if (word[0] == '-')
{
negative = 1;
len--;
word++;
}
else if (word[0] == '+')
{
len--;
word++;
}
for (i = 0; i < len; i++)
{
c = *word;
word++;
if (c == '.') { *isDouble = 1; continue; }
else if (c >= '0' && c <= '9') current = c - '0';
else if (c >= 'A' && c <= 'Z') current = 10 + c - 'A';
else if (c >= 'a' && c <= 'z') current = 10 + c - 'a';
else break;
if (current >= *base) break;
*number = *number * *base + current;
}
*notRead = len - i;
if (negative) *number = (-((scell)*number));
}
/*******************************************************************************
*
* Builtin definitions
*
*******************************************************************************/
BUILTIN(0, "RUNDOCOL", docol, 0)
{
rpush(lastIp);
next = commandAddress + CELL_SIZE;
}
/* The first few builtins are very simple, not need to waste vertical space here */
BUILTIN( 1, "CELL", doCellSize, 0) { push(CELL_SIZE); }
BUILTIN( 2, "@", memRead, 0) { push(readMem(pop())); }
BUILTIN( 3, "C@", memReadByte, 0) { push(memory[pop()]); }
BUILTIN( 4, "KEY", key, 0) { push(getkey()); }
BUILTIN( 5, "EMIT", emit, 0) { putkey(pop() & 255); }
BUILTIN( 6, "DROP", drop, 0) { pop(); }
BUILTIN( 7, "EXIT", doExit, 0) { next = rpop(); }
BUILTIN( 8, "BYE", bye, 0) { exitReq = 1; }
BUILTIN( 9, "LATEST", doLatest, 0) { push(LATEST_POSITION); }
BUILTIN(10, "HERE", doHere, 0) { push(HERE_POSITION); }
BUILTIN(11, "BASE", doBase, 0) { push(BASE_POSITION); }
BUILTIN(12, "STATE", doState, 0) { push(STATE_POSITION); }
BUILTIN(13, "[", gotoInterpreter, FLAG_IMMEDIATE) { *state = 0; }
BUILTIN(14, "]", gotoCompiler, 0) { *state = 1; }
BUILTIN(15, "HIDE", hide, 0) { memory[*latest + CELL_SIZE] ^= FLAG_HIDDEN; }
BUILTIN(16, "R>", rtos, 0) { push(rpop()); }
BUILTIN(17, ">R", stor, 0) { rpush(pop()); }
BUILTIN(18, "KEY?", key_p, 0) { push(keyWaiting()); }
BUILTIN(19, "BRANCH", branch, 0) { next += readMem(next); }
BUILTIN(20, "0BRANCH", zbranch, 0) { next += pop() ? CELL_SIZE : readMem(next); }
BUILTIN(21, "IMMEDIATE", toggleImmediate, FLAG_IMMEDIATE) { memory[*latest + CELL_SIZE] ^= FLAG_IMMEDIATE; }
BUILTIN(22, "FREE", doFree, 0) { push(MEM_SIZE - *here); }
BUILTIN(23, "S0@", s0_r, 0) { push(STACK_POSITION + CELL_SIZE); }
BUILTIN(24, "DSP@", dsp_r, 0) { push(STACK_POSITION + *sp * CELL_SIZE); }
BUILTIN(25, "NOT", not, 0) { push(~pop()); }
BUILTIN(26, "DUP", dup, 0) { push(tos()); }
BUILTIN(27, "!", memWrite, 0)
{
cell address = pop();
cell value = pop();
writeMem(address, value);
}
BUILTIN(28, "C!", memWriteByte, 0)
{
cell address = pop();
cell value = pop();
memory[address] = value & 255;
}
BUILTIN(29, "SWAP", swap, 0)
{
cell a = pop();
cell b = pop();
push(a);
push(b);
}
BUILTIN(30, "OVER", over, 0)
{
cell a = pop();
cell b = tos();
push(a);
push(b);
}
BUILTIN(31, ",", comma, 0)
{
push(*here);
memWrite();
*here += CELL_SIZE;
}
BUILTIN(32, "C,", commaByte, 0)
{
push(*here);
memWriteByte();
*here += sizeof(byte);
}
BUILTIN(33, "WORD", word, 0)
{
byte len = readWord();
push(1);
push(len);
}
BUILTIN(34, "FIND", find, 0)
{
cell len = pop();
cell address = pop();
cell ret = findWord(address, len);
push(ret);
}
cell getCfa(cell address)
{
byte len = (memory[address + CELL_SIZE] & MASK_NAMELENGTH) + 1;
while ((len & (CELL_SIZE-1)) != 0) len++;
return address + CELL_SIZE + len;
}
BUILTIN(35, ">CFA", cfa, 0)
{
cell address = pop();
cell ret = getCfa(address);
if (ret < maxBuiltinAddress)
push(readMem(ret));
else
push(ret);
}
BUILTIN(36, "NUMBER", number, 0)
{
dcell num;
cell notRead;
byte isDouble;
cell len = pop();
byte* address = &memory[pop()];
parseNumber(address, len, &num, &notRead, &isDouble);
if (isDouble) dpush(num); else push((cell)num);
push(notRead);
}
BUILTIN(37, "LIT", lit, 0)
{
push(readMem(next));
next += CELL_SIZE;
}
/* Outer and inner interpreter, TODO split up */
BUILTIN(38, "QUIT", quit, 0)
{
cell address;
dcell number;
cell notRead;
cell command;
int i;
byte isDouble;
cell tmp[2];
int immediate;
for (exitReq = 0; exitReq == 0;)
{
lastIp = next = quit_address;
errorFlag = 0;
word();
find();
address = pop();
if (address)
{
immediate = (memory[address + CELL_SIZE] & FLAG_IMMEDIATE);
commandAddress = getCfa(address);
command = readMem(commandAddress);
if (*state && !immediate)
{
if (command < MAX_BUILTIN_ID && command != docol_id)
push(command);
else
push(commandAddress);
comma();
}
else
{
while (!errorFlag && !exitReq)
{
if (command == quit_id) break;
else if (command < MAX_BUILTIN_ID) builtins[command]();
else
{
lastIp = next;
next = command;
}
commandAddress = next;
command = readMem(commandAddress);
next += CELL_SIZE;
}
}
}
else
{
parseNumber(&memory[1], memory[0], &number, &notRead, &isDouble);
if (notRead)
{
tell("Unknown word: ");
for (i=0; i<memory[0]; i++)
putkey(memory[i+1]);
putkey('\n');
*sp = *rsp = 1;
continue;
}
else
{
if (*state)
{
*((dcell*)tmp) = number;
push(lit_id);
comma();
if (isDouble)
{
push(tmp[0]);
comma();
push(lit_id);
comma();
push(tmp[1]);
comma();
}
else
{
push((cell)number);
comma();
}
}
else
{
if (isDouble) dpush(number); else push((cell)number);
}
}
}
if (errorFlag)
*sp = *rsp = 1;
else if (!keyWaiting() && !(*initscript_pos))
tell(" OK\n");
}
}
BUILTIN(39, "+", plus, 0)
{
scell n1 = pop();
scell n2 = pop();
push(n1 + n2);
}
BUILTIN(40, "-", minus, 0)
{
scell n1 = pop();
scell n2 = pop();
push(n2 - n1);
}
BUILTIN(41, "*", mul, 0)
{
scell n1 = pop();
scell n2 = pop();
push(n1 * n2);
}
BUILTIN(42, "/MOD", divmod, 0)
{
scell n1 = pop();
scell n2 = pop();
push(n2 % n1);
push(n2 / n1);
}
BUILTIN(43, "ROT", rot, 0)
{
cell a = pop();
cell b = pop();
cell c = pop();
push(b);
push(a);
push(c);
}
void createWord(const char* name, byte len, byte flags);
BUILTIN(44, "CREATE", doCreate, 0)
{
byte len;
cell address;
word();
len = pop() & 255;
address = pop();
createWord((char*)&memory[address], len, 0);
}
BUILTIN(45, ":", colon, 0)
{
doCreate();
push(docol_id);
comma();
hide();
*state = 1;
}
BUILTIN(46, ";", semicolon, FLAG_IMMEDIATE)
{
push(doExit_id);
comma();
hide();
*state = 0;
}
BUILTIN(47, "R@", rget, 0)
{
cell tmp = rpop();
rpush(tmp);
push(tmp);
}
BUILTIN(48, "J", doJ, 0)
{
cell tmp1 = rpop();
cell tmp2 = rpop();
cell tmp3 = rpop();
rpush(tmp3);
rpush(tmp2);
rpush(tmp1);
push(tmp3);
}
BUILTIN(49, "'", tick, FLAG_IMMEDIATE)
{
word();
find();
cfa();
if (*state)
{
push(lit_id);
comma();
comma();
}
}
BUILTIN(50, "=", equals, 0)
{
cell a1 = pop();
cell a2 = pop();
push(a2 == a1 ? -1 : 0);
}
BUILTIN(51, "<", smaller, 0)
{
scell a1 = pop();
scell a2 = pop();
push(a2 < a1 ? -1 : 0);
}
BUILTIN(52, ">", larger, 0)
{
scell a1 = pop();
scell a2 = pop();
push(a2 > a1 ? -1 : 0);
}
BUILTIN(53, "AND", doAnd, 0)
{
cell a1 = pop();
cell a2 = pop();
push(a2 & a1);
}
BUILTIN(54, "OR", doOr, 0)
{
cell a1 = pop();
cell a2 = pop();
push(a2 | a1);
}
BUILTIN(55, "?DUP", p_dup, 0)
{
cell a = tos();
if (a) push(a);
}
BUILTIN(56, "LITSTRING", litstring, 0)
{
cell length = readMem(next);
next += CELL_SIZE;
push(next);
push(length);
next += length;
while (next & (CELL_SIZE-1))
next++;
}
BUILTIN(57, "XOR", xor, 0)
{
cell a = pop();
cell b = pop();
push(a ^ b);
}
BUILTIN(58, "*/", timesDivide, 0)
{
cell n3 = pop();
dcell n2 = pop();
dcell n1 = pop();
dcell r = (n1 * n2) / n3;
push((cell)r);
if ((cell)r != r)
{
tell("Arithmetic overflow\n");
errorFlag = 1;
}
}
BUILTIN(59, "*/MOD", timesDivideMod, 0)
{
cell n3 = pop();
dcell n2 = pop();
dcell n1 = pop();
dcell r = (n1 * n2) / n3;
dcell m = (n1 * n2) % n3;
push((cell)m);
push((cell)r);
if ((cell)r != r)
{
tell("Arithmetic overflow\n");
errorFlag = 1;
}
}
BUILTIN(60, "D=", dequals, 0)
{
dcell a1 = dpop();
dcell a2 = dpop();
push(a2 == a1 ? -1 : 0);
}
BUILTIN(61, "D<", dsmaller, 0)
{
dscell a1 = dpop();
dscell a2 = dpop();
push(a2 < a1 ? -1 : 0);
}
BUILTIN(62, "D>", dlarger, 0)
{
dscell a1 = dpop();
dscell a2 = dpop();
push(a2 > a1 ? -1 : 0);
}
BUILTIN(63, "DU<", dusmaller, 0)
{
dcell a1 = dpop();
dcell a2 = dpop();
push(a2 < a1 ? -1 : 0);
}
BUILTIN(64, "D+", dplus, 0)
{
dscell n1 = dpop();
dscell n2 = dpop();
dpush(n1 + n2);
}
BUILTIN(65, "D-", dminus, 0)
{
dscell n1 = dpop();
dscell n2 = dpop();
dpush(n2 - n1);
}
BUILTIN(66, "D*", dmul, 0)
{
dscell n1 = dpop();
dscell n2 = dpop();
dpush(n1 * n2);
}
BUILTIN(67, "D/", ddiv, 0)
{
dscell n1 = dpop();
dscell n2 = dpop();
dpush(n2 / n1);
}
BUILTIN(68, "2SWAP", dswap, 0)
{
dcell a = dpop();
dcell b = dpop();
dpush(a);
dpush(b);
}
BUILTIN(69, "2OVER", dover, 0)
{
dcell a = dpop();
dcell b = dpop();
dpush(b);
dpush(a);
dpush(b);
}
BUILTIN(70, "2ROT", drot, 0)
{
dcell a = dpop();
dcell b = dpop();
dcell c = dpop();
dpush(b);
dpush(a);
dpush(c);
}
/*******************************************************************************
*
* Loose ends
*
*******************************************************************************/
/* Create a word in the dictionary */
void createWord(const char* name, byte len, byte flags)
{
cell newLatest = *here;
push(*latest);
comma();
push(len | flags);
commaByte();
while (len--)
{
push(*name);
commaByte();
name++;
}
while (*here & (CELL_SIZE-1))
{
push(0);
commaByte();
}
*latest = newLatest;
}
/* A simple strlen clone so we don't have to pull in string.h */
byte slen(const char *str)
{
byte ret = 0;
while (*str++) ret++;
return ret;
}
/* Add a builtin to the dictionary */
void addBuiltin(cell code, const char* name, const byte flags, builtin f)
{
if (errorFlag) return;
if (code >= MAX_BUILTIN_ID)
{
tell("Error adding builtin ");
tell(name);
tell(": Out of builtin IDs\n");
errorFlag = 1;
return;
}
if (builtins[code] != 0)
{
tell("Error adding builtin ");
tell(name);
tell(": ID given twice\n");
errorFlag = 1;
return;
}
builtins[code] = f;
createWord(name, slen(name), flags);
push(code);
comma();
push(doExit_id);
comma();
}
/* Program setup and jump to outer interpreter */
int main()
{
errorFlag = 0;
if (DCELL_SIZE != 2*CELL_SIZE)
{
tell("Configuration error: DCELL_SIZE != 2*CELL_SIZE\n");
return 1;
}
state = (cell*)&memory[STATE_POSITION];
base = (cell*)&memory[BASE_POSITION];
latest = (cell*)&memory[LATEST_POSITION];
here = (cell*)&memory[HERE_POSITION];
sp = (cell*)&memory[STACK_POSITION];
stack = (cell*)&memory[STACK_POSITION + CELL_SIZE];
rsp = (cell*)&memory[RSTACK_POSITION];
rstack = (cell*)&memory[RSTACK_POSITION + CELL_SIZE];
*sp = *rsp = 1;
*state = 0;
*base = 10;
*latest = 0;
*here = HERE_START;
ADD_BUILTIN(docol);
ADD_BUILTIN(doCellSize);
ADD_BUILTIN(memRead);
ADD_BUILTIN(memWrite);
ADD_BUILTIN(memReadByte);
ADD_BUILTIN(memWriteByte);
ADD_BUILTIN(key);
ADD_BUILTIN(emit);
ADD_BUILTIN(swap);
ADD_BUILTIN(dup);
ADD_BUILTIN(drop);
ADD_BUILTIN(over);
ADD_BUILTIN(comma);
ADD_BUILTIN(commaByte);
ADD_BUILTIN(word);
ADD_BUILTIN(find);
ADD_BUILTIN(cfa);
ADD_BUILTIN(doExit);
ADD_BUILTIN(quit);
quit_address = getCfa(*latest);
ADD_BUILTIN(number);
ADD_BUILTIN(bye);
ADD_BUILTIN(doLatest);
ADD_BUILTIN(doHere);
ADD_BUILTIN(doBase);
ADD_BUILTIN(doState);
ADD_BUILTIN(plus);
ADD_BUILTIN(minus);
ADD_BUILTIN(mul);
ADD_BUILTIN(divmod);
ADD_BUILTIN(rot);
ADD_BUILTIN(gotoInterpreter);
ADD_BUILTIN(gotoCompiler);
ADD_BUILTIN(doCreate);
ADD_BUILTIN(hide);
ADD_BUILTIN(lit);
ADD_BUILTIN(colon);
ADD_BUILTIN(semicolon);
ADD_BUILTIN(rtos);
ADD_BUILTIN(stor);
ADD_BUILTIN(rget);
ADD_BUILTIN(doJ);
ADD_BUILTIN(tick);
ADD_BUILTIN(key_p);
ADD_BUILTIN(equals);
ADD_BUILTIN(smaller);
ADD_BUILTIN(larger);
ADD_BUILTIN(doAnd);
ADD_BUILTIN(doOr);
ADD_BUILTIN(branch);
ADD_BUILTIN(zbranch);
ADD_BUILTIN(toggleImmediate);
ADD_BUILTIN(doFree);
ADD_BUILTIN(p_dup);
ADD_BUILTIN(s0_r);
ADD_BUILTIN(dsp_r);
ADD_BUILTIN(litstring);
ADD_BUILTIN(not);
ADD_BUILTIN(xor);
ADD_BUILTIN(timesDivide);
ADD_BUILTIN(timesDivideMod);
ADD_BUILTIN(dequals);
ADD_BUILTIN(dsmaller);
ADD_BUILTIN(dlarger);
ADD_BUILTIN(dusmaller);
ADD_BUILTIN(dplus);
ADD_BUILTIN(dminus);
ADD_BUILTIN(dmul);
ADD_BUILTIN(ddiv);
ADD_BUILTIN(dswap);
ADD_BUILTIN(dover);
ADD_BUILTIN(drot);
maxBuiltinAddress = (*here) - 1;
if (errorFlag) return 1;
initscript_pos = (char*)initScript;
quit();
return 0;
}
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