CamelForth
Resources
Basics
Stack manipulation
1 2 3 / put 1 2 and 3 on stack
. / pip from stack and dispaly
.s / show stack (gfort)
2 dup / duplicate: 2 2
1 2 swap / swap 2 items: 2 1
1 2 over / copy secondmost item to top: 1 2 1
1 2 drop / drop top item: 1
1 2 3 rot / move thirdmost item to top: 2 3 1
Words
TABLE 1. GLOSSARY OF WORDS IN CAMEL80.AZM
Words which are (usually) written in CODE.
NAME stack in -- stack out description
Guide to stack diagrams: R: = return stack,
c = 8-bit character, flag = boolean (0 or -1),
n = signed 16-bit, u = unsigned 16-bit,
d = signed 32-bit, ud = unsigned 32-bit,
+n = unsigned 15-bit, x = any cell value,
i*x j*x = any number of cell values,
a-addr = aligned adrs, c-addr = character adrs
p-addr = I/O port adrs, sys = system-specific.
Refer to ANS Forth document for more details.
ANS Forth Core words
These are required words whose definitions are
specified by the ANS Forth document.
! x a-addr -- store cell in memory
+ n1/u1 n2/u2 -- n3/u3 add n1+n2
+! n/u a-addr -- add cell to memory
- n1/u1 n2/u2 -- n3/u3 subtract n1-n2
< n1 n2 -- flag test n1<n2, signed
= x1 x2 -- flag test x1=x2
> n1 n2 -- flag test n1>n2, signed
>R x -- R: -- x push to return stack
?DUP x -- 0 | x x DUP if nonzero
@ a-addr -- x fetch cell from memory
0< n -- flag true if TOS negative
0= n/u -- flag return true if TOS=0
1+ n1/u1 -- n2/u2 add 1 to TOS
1- n1/u1 -- n2/u2 subtract 1 from TOS
2* x1 -- x2 arithmetic left shift
2/ x1 -- x2 arithmetic right shift
AND x1 x2 -- x3 logical AND
CONSTANT n -- define a Forth constant
C! c c-addr -- store char in memory
C@ c-addr -- c fetch char from memory
DROP x -- drop top of stack
DUP x -- x x duplicate top of stack
EMIT c -- output character to console
EXECUTE i*x xt -- j*x execute Forth word 'xt'
EXIT -- exit a colon definition
FILL c-addr u c -- fill memory with char
I -- n R: sys1 sys2 -- sys1 sys2
get the innermost loop index
INVERT x1 -- x2 bitwise inversion
J -- n R: 4*sys -- 4*sys
get the second loop index
KEY -- c get character from keyboard
LSHIFT x1 u -- x2 logical L shift u places
NEGATE x1 -- x2 two's complement
OR x1 x2 -- x3 logical OR
OVER x1 x2 -- x1 x2 x1 per stack diagram
ROT x1 x2 x3 -- x2 x3 x1 per stack diagram
RSHIFT x1 u -- x2 logical R shift u places
R> -- x R: x -- pop from return stack
R@ -- x R: x -- x fetch from rtn stk
SWAP x1 x2 -- x2 x1 swap top two items
UM* u1 u2 -- ud unsigned 16x16->32 mult.
UM/MOD ud u1 -- u2 u3 unsigned 32/16->16 div.
UNLOOP -- R: sys1 sys2 -- drop loop parms
U< u1 u2 -- flag test u1<n2, unsigned
VARIABLE -- define a Forth variable
XOR x1 x2 -- x3 logical XOR
ANS Forth Extensions
These are optional words whose definitions are
specified by the ANS Forth document.
<> x1 x2 -- flag test not equal
BYE i*x -- return to CP/M
CMOVE c-addr1 c-addr2 u -- move from bottom
CMOVE> c-addr1 c-addr2 u -- move from top
KEY? -- flag return true if char waiting
M+ d1 n -- d2 add single to double
NIP x1 x2 -- x2 per stack diagram
TUCK x1 x2 -- x2 x1 x2 per stack diagram
U> u1 u2 -- flag test u1>u2, unsigned
Private Extensions
These are words which are unique to CamelForth.
Many of these are necessary to implement ANS
Forth words, but are not specified by the ANS
document. Others are functions I find useful.
(do) n1|u1 n2|u2 -- R: -- sys1 sys2
run-time code for DO
(loop) R: sys1 sys2 -- | sys1 sys2
run-time code for LOOP
(+loop) n -- R: sys1 sys2 -- | sys1 sys2
run-time code for +LOOP
>< x1 -- x2 swap bytes
?branch x -- branch if TOS zero
BDOS DE C -- A call CP/M BDOS
branch -- branch always
lit -- x fetch inline literal to stack
PC! c p-addr -- output char to port
PC@ p-addr -- c input char from port
RP! a-addr -- set return stack pointer
RP@ -- a-addr get return stack pointer
SCAN c-addr1 u1 c -- c-addr2 u2
find matching char
SKIP c-addr1 u1 c -- c-addr2 u2
skip matching chars
SP! a-addr -- set data stack pointer
SP@ -- a-addr get data stack pointer
S= c-addr1 c-addr2 u -- n string compare
n<0: s1<s2, n=0: s1=s2, n>0: s1>s2
USER n -- define user variable 'n'
