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Dictionary¶
Example Dictionary Listing¶
Address: 0000DFD4 Link: 0000DFEC Flags: 00000040 Code: 0000DFE4 Name: pull-down
Address: 0000DFEC Link: 0000E024 Flags: 00001820 Code: 0000DFFC Name: green-on
Address: 0000E024 Link: 0000E05C Flags: 00001820 Code: 0000E034 Name: green-off
see green-on
0000DFFC: 2090 movs r0 #90
0000DFFE: 04C0 lsls r0 r0 #13
0000E000: 3080 adds r0 #80
0000E002: 0100 lsls r0 r0 #4
0000E004: 6983 ldr r3 [ r0 #18 ]
0000E006: 2280 movs r2 #80
0000E008: 0092 lsls r2 r2 #2
0000E00A: 4313 orrs r3 r2
0000E00C: 6183 str r3 [ r0 #18 ]
0000E00E: 4770 bx lr
Forth Definition Components¶
Address Link Flags Code Name
Word Header Fields¶
Name |
Description |
|---|---|
ADDRESS |
Start of the definition block, always 16 Bytes before the CODE section |
LINK |
Address of the next definition, the one after this one |
FLAGS |
see “FLAG Codes” below |
CODE |
The address of the start of the executable code for this Word. Call this address to execute this Word. |
NAME |
The name of the definition (Word) |
FLAG Codes¶
Taken from: mecrisp-stellaris-source/common/datastackandmacros.s
Flag |
RA Only? |
Description |
|---|---|---|
0x0000 |
Visible, non-immediate |
|
0x0008 |
Opcodable; 0: special case 1: plusminus 2: computational logic 3: DC unequal 4: push 5: memory Write, |
|
0x0010 |
Immediate |
|
0x0020 |
Inline - that means, it’s contents will be inlined until $4130, the ret opcode is found. On ARM, this is either $4770 bx lr or $BD00 pop {pc}. |
|
0x0030 |
Immediate+Inline means: Immediate, Compile-Only |
|
0x0080 |
Ramallot means that RAM is reserved and initialised by catchflashpointers for this definition on startup |
|
0x0040 |
0-foldable, e.g. constants |
|
0x0041 |
1-foldable, e.g. 1+ |
|
0x0042 |
2-foldable, e.g. swap, xor |
|
0x0043 |
3-foldable |
|
0x0044 |
4-foldable |
|
0x0045 |
5-foldable |
|
0x0046 |
6-foldable |
|
0x0047 |
7-foldable |
|
0x0100 |
buffers in compiletoflash mode |
|
0x0200 |
Y |
Allocator, this definition has individal optimisation code and a second entry point for the optimiser after the first bx lr or pop {pc} opcode. |
0x0400 |
Y |
Jump Eaters, this definition can handle cached jump instructions itself, for merging of comparisons with control structures. |
0x0800 |
Y |
Bxlr, is used once for ; and means that despite ; is immediate we can keep the direct bx lr return without the need to write the push {lr} opcode first for a later pop {pc}. Usually, the optimiser falls back to the push {lr} … pop {pc} sequence as soon as a call is compiled or something flagged as immediate is encountered. |
0x1000 |
Y |
Inlinecache, denotes that this definition carries an automatically generated inline cache table, which allows recompilation of this definition elsewhere with local optimisations in place. |
0x2000 |
Y |
Literator, never shows up in the dictionary, but appears in inline cache table to denote literals instead of code entry point with flag pairs. |
0x4000 |
Y |
User, is unused in all Mecrisp-Stellaris cores. This flag is free for the user, and the loadable vocabulary extension relies on it. |
0xFFFF |
Invisible |
RA Core Register Usage¶
Register Purpose Notes
r0 Free scratch register Saved on interrupt entry by hardware r1 Free scratch register Saved on interrupt entry by hardware r2: Free scratch register Saved on interrupt entry by hardware r3: Free scratch register Saved on interrupt entry by hardware
r4: Inner loop count Needs Push and Pop when used otherwise r5: Inner loop limit Needs Push and Pop when used otherwise
r6=TOS: Top-Of-Stack Stack design is interrupt safe ) r7=PSP: Parameter Stack Pointer Stack design is interrupt safe )
r8: Unused r9: Unused r10: Unused r11: Unused r12: Unused Saved on interrupt entry by hardware
r13=SP: Return Stack Pointer r14=LR: Link Register r15=PC: Program Counter, always odd
Number Bases¶
prefix |
Base |
exactly ANS |
|
|---|---|---|---|
% |
binary |
( - - ) |
Sets base to 2 |
# |
decimal |
( - - ) |
Sets base to 10 |
$ |
hex |
( - - ) |
Sets base to 16 |
base |
( - - a-addr ) |
Base variable address |
|
Data Types¶
Name |
Bits |
Description |
|---|---|---|
Word |
32 |
Native Mecrisp-Stellaris data length |
Cell |
32 |
Same as Word above |
Half Word |
16 |
Half Word length |
Character |
8 |
One Byte |
Bit |
1 |
Smallest |
Key to Tables¶
Phrase |
Description |
Comment |
Examples |
|---|---|---|---|
n, n1, |
single-length signed integer |
-2147483648 to 2147483647 |
$80000000 . -2147483648, $7FFFFFFF . 2147483647 |
d, d1, |
double-length signed integer |
-9,223,372,036,854,775,808 to 9,223,372,036,854,775,807 |
$FFFFFFFF $FFFFFFFF m* d. 1 ok. ( -1 * -1 = 1 ) |
u, u1, |
single-length unsigned integer |
0 to 4294967295 |
$FFFFFFFF u. 4294967295, |
ud, ud1 |
unsigned double-length integer |
0 to 18,446,744,065,119,617,025 |
$FFFFFFFF $FFFFFFFF um* ud. 18446744065119617025 |
c |
character (byte) |
8 bits, 0 to 255 |
$FF |
h |
halfword |
16 bits, 0 to 65,535 |
$FFFF |
x |
cell |
logic, memory operations, logging, bitmaps … |
|
a-addr |
cell address |
||
h-addr |
half word address |
||
c-addr |
character (byte) address |
||
R: |
return stack |
||
flag |
Binary 1 or 0 |
||
“name” |
input stream token |
Compiler Error Messages¶
Derived by grepping the source for “write”, “writeln” and “Fehler” (error).
Message |
Source |
Comments |
|---|---|---|
Jump too far |
Dreaded conditional jump range limitation. Workaround: create new Word with offending code. |
|
Cannot write into core ! |
flash16bytesblockwrite.s |
|
Cannot write into core ! |
flash.s |
|
Create needs name ! |
compiler-flash.s |
Often caused by a lone “;” |
Flash full |
compiler-flash.s |
The chip Flash Memory is full. |
interpreter.s |
Cannot be used interactively, must be inside a Definition (Word) |
|
controlstructures.s |
All jumps use Thumb 1 short opcodes. Solution; split your code into smaller Words |
|
Not enough RAM |
compiler-flash.s |
Not enough RAM is available to complete the Word |
not found. |
interpreter.s |
Name of word, constant, variable, etc cannot be found, usually a source typo |
ok. |
interpreter.s |
All is good! |
Ram full |
compiler-flash.s |
The chip RAM is full |
Redefine |
compiler-flash.s |
A Word, constant, variable, etc has been defined more than once |
Stack underflow |
interpreter.s |
The Data Stack is empty, you tried to pop data off it, but there is no data there |
Stack not balanced. |
compiler.s |
The Return Stack is unbalanced, use of >R and R> was not equal |
Stack overflow |
interpreter.s |
The Data Stack is full, default size is 64 elements, same as the Return Stack. |
Structures don’t match |
controlstructures.s |
Example: a missing “then” from a “if else then” statement |
Unhandled Interrupt ! |
interrupts-common.s |
A Interrupt has been triggered, but no code is handling it. See Exceptions |
Variables collide with dictionary |
compiler-flash.s |
|
Wrong address or data for writing flash ! |
flash.s for your MCU |
See notes |
Terminal-IO¶
Exactly ANS, some logical extension |
||
|---|---|---|
emit? |
( - - Flag ) |
Ready to send a character ? |
key? |
( - - Flag ) |
Checks if a key is waiting |
key |
( - - Char ) |
Waits for and fetches the pressed key |
emit |
( Char - - ) |
Emits a character |
hook-emit? |
( - - a-addr ) |
Hooks for redirecting terminal IO on the fly |
hook-key? |
||
hook-key |
||
hook-emit |
||
serial-emit? |
( - - Flag ) |
Serial interface terminal routines as default communications |
serial-key? |
||
serial-key |
( - - Char ) |
Waits for and fetches the pressed key |
serial-emit |
( Char - - ) |
Emits a character |
hook-pause |
( - - a-addr ) |
Hook for a multitasker |
pause |
( - - ) |
Task switch, none for default |
Character Manipulation¶
How to convert numbers to characters and convert characters to numbers.
Command |
Stack Notation |
Description |
Code or Comment |
Result |
|---|---|---|---|---|
[char] * |
( - - char ) |
Compiles code of following char when executed |
When used in a definition (function, Word) |
|
char * |
( - - char ) |
Gives code of following char |
char 3 hex. |
00000033 ok. |
emit |
( char - - ) |
Emits a character |
$33 emit |
3 ok. |
Stack Jugglers¶
Single-Jugglers¶
Exactly ANS, some logical extension |
RA Core Only ? |
||
|---|---|---|---|
depth |
( - - +n ) |
Gives number of single-cell stack items. |
|
nip |
( x1 x2 - - x2 ) |
Drop the first item below the top of the stack |
|
drop |
( x - - ) |
||
rot |
( x1 x2 x3 - - x2 x3 x1 ) |
||
-rot |
( x1 x2 x3 - - x3 x1 x2 ) |
||
swap |
( x1 x2 - - x2 x1 ) |
||
tuck |
( x1 x2 - - x2 x1 x2 ) |
||
over |
( x1 x2 - - x1 x2 x1 ) |
||
?dup |
( x - - 0 | x x ) |
||
dup |
( x - - x x ) |
||
pick |
( … xi+1 xi … x1 x0 i - - … x1 x0 xi ) |
Copy a element X levels down the stack to the top of the stack |
|
>r |
( x - - ) (R: - - x ) |
Push to Return Stack (the Return Stack must be balanced) |
|
r> |
( - - x ) (R: x - - ) |
Pull from Return Stack |
|
r@ |
( - - x ) (R: x - - x ) |
Copy from Return Stack |
|
rdrop |
( - - ) (R: x - - ) |
||
rdepth |
( - - +n ) |
Gives number of return stack items. |
|
rpick |
( i - - xi ) R: ( … xi … x0 - - … xi … x0 ) |
||
( xu xu-1 … x0 u – xu-1 … x0 xu ) |
Remove u. Rotate u+1 items on the top of the stack. |
Yes |
|
( xu-1 … x0 xu u – xu xu-1 … x0 ) |
Yes |
||
Double-Jugglers¶
They perform the same for double numbers |
|
|---|---|
2nip |
( x1 x2 x3 x4 - -x3 x4 ) |
2drop |
( x1 x2 - - ) |
2rot |
( x1 x2 x3 x4 x5 x6 - - x3 x4 x5 x6 x1 x2 ) |
2-rot |
( x1 x2 x3 x4 x5 x6 - - x5 x6 x1 x2 x3 x4 ) |
2swap |
( x1 x2 x3 x4 - - x3 x4 x1 x2 ) |
2tuck |
( x1 x2 x3 x4 - - x3 x4 x1 x2 x3 x4 ) |
2over |
( x1 x2 x3 x4 - - x1 x2 x3 x4 x1 x2 ) |
2dup |
( x1 x2 - - x1 x2 x1 x2 ) |
2>r |
( x1 x2 - - ) (R: - -x1 x2 ) |
2r> |
( - - x1 x2 ) (R: x1 x2 - - ) |
2r@ |
( - - x1 x2 ) (R: x1 x2 - -x1 x2 ) |
2rdrop |
( - - ) (R: x1 x2 - - ) |
Stack pointers¶
Stack Pointers |
||
|---|---|---|
sp@ |
( - - a-addr ) |
Fetch data stack pointer |
sp! |
( a-addr - - ) |
Store data stack pointer |
rp@ |
( - - a-addr ) |
Fetch return stack pointer |
rp! |
( a-addr - - ) |
Store return stack pointer |
Logic¶
exactly ANS, some logical extensions |
||
|---|---|---|
arshift |
( x1 u - - x2 ) |
Arithmetric right-shift of u bit-places |
rshift |
( x1 u - - x2 ) |
Logical right-shift of u bit-places |
lshift |
( x1 u - - x2 ) |
Logical left-shift of u bit-places |
shr |
( x1 - - x2 ) |
Logical right-shift of one bit-place |
shl |
( x1 - - x2 ) |
Logical left-shift of one bit-place |
ror |
( x1 - - x2 ) |
Logical right-rotation of one bit-place |
rol |
( x1 - - x2 ) |
Logical left-rotation of one bit-place |
bic |
( x1 x2 - - x3 ) |
Bit clear, identical to “not and” |
not |
( x1 - - x2 ) |
Invert all bits |
xor |
( x1 x2 - - x3 ) |
Bitwise Exclusive-OR |
or |
( x1 x2 - - x3 ) |
Bitwise OR |
and |
( x1 x2 - - x3 ) |
Bitwise AND |
false |
( - - 0 ) |
False-Flag |
true |
( - - -1 ) |
True-Flag |
clz |
( x1 - - u ) |
Count leading zeros |
Single Number Math¶
exactly ANS |
some logical extensions |
|
|---|---|---|
u/mod |
( u1 u2 - - u3 u4 ) |
32/32 = 32 rem 32 Division u1 / u2 = u4 remainder u3 |
/mod |
( n1 n2 - - n3 n4 ) |
n1 / n2 = n4 rem n3 |
mod |
( n1 n2 - - n3 ) |
n1 / n2 = remainder n3 |
/ |
( n1 n2 - - n3 ) |
n1 / n2 = n3 |
* |
( u1 n1 u2 n2 - - u3 n3 ) |
32*32 = 32 Multiplication |
( n1 n2 - - n1 n2 ) |
Keeps smaller of top two items |
|
( n1 n2 - - n1 n2 ) |
Keeps greater of top two items |
|
( u1 u2 - - u1 u2 ) |
Keeps unsigned smaller |
|
( u1 u2 - - u1 u2 ) |
Keeps unsigned greater |
|
2- |
( u1 n1 - - u2 n2 ) |
Subtracts two, optimized |
1- |
( u1 n1 - - u2 n2 ) |
Subtracts one, optimized |
2+ |
( u1 n1 - - u2 n2 ) |
Adds two, optimized |
1+ |
( u1 n1 - - u2 n2 ) |
Adds one, optimized |
even |
( u1 n1 - - u2 n2 ) |
Makes even. Adds one if uneven. |
2* |
( n1 - - n2 ) |
Arithmetric left-shift |
2/ |
( n1 - - n2 ) |
Arithmetric right-shift |
abs |
( n - - u ) |
Absolute value |
negate |
( n1 - - n2 ) |
Negate |
- |
( u1|n1 u2|n2 - - u3|n3 ) |
Subtraction |
+ |
( u1|n1 u2|n2 - - u3|n3 ) |
Addition |
Double Number Math¶
exactly ANS, some logical extensions |
||
|---|---|---|
um* |
( u1 u2 - - ud ) |
32*32 = 64 Multiplication |
ud* |
( ud1 ud2 - - ud3 ) |
64*64 = 64 Multiplication |
udm* |
(ud1 ud2 - - ud3-Low ud4-High ) |
64*64=128 Multiplication |
um/mod |
( ud u1 - - u2 u3 ) |
ud / u1 = u3 remainder u2 |
ud/mod |
( ud1 ud2 - - ud3 ud4 ) |
64/64 = 64 rem 64 Division ud1 / ud2 = ud4 remainder ud3 |
m* |
( n1 n2 - - d ) |
n1 * n2 = d |
m/mod |
( d n1 - - n2 n3 ) |
d / n1 = n3 remainder r2 |
d/mod |
( d1 d2 - - d3 d4 ) |
d1 / d2 = d4 remainder d3 |
d/ |
( d1 d2 - - d3 ) |
d1 / d2 = d3 |
*/ |
( n1 n2 n3 - - n4 ) |
n1 * n2 / n3 = n4 |
u*/ |
( u1 u2 u3 - - u4 ) |
u1 * u2 / u3 = u4 |
*/mod |
( n1 n2 n3 - - n4 n5 ) |
n1 * n2 / n3 = n5 remainder n4 |
u*/mod |
( u1 u2 u3 - - u4 u5 ) |
u1 * u2 / u3 = u5 remainder u4 |
d2* |
( d1 - - d2 ) |
Arithmetric left-shift |
d2/ |
( d1 - - d2 ) |
Arithmetric right-shift |
dshl |
( ud1 - - ud2 ) |
Logical left-shift, same as d2* |
dshr |
( ud1 - - ud2 ) |
Logical right-shift |
dabs |
( d - - ud ) |
Absolute value |
dnegate |
( d1 - - d2 ) |
Negate |
d- |
( ud1|d1 ud2|d2 - - ud3|d3 ) |
Subtraction |
d+ |
( ud1|d1 ud2|d2 - - ud3|d3 ) |
Addition |
s>d |
( n - - d ) |
Turn a single into a double |
Fixed Point Arithmetic¶
See also
Fixed Point Page Fixed Point Examples
s31.32 fixed point numbers, speciality!
Fixpoint numbers are stored ( n-comma n-whole ) and can be handled like signed double numbers |
||
|---|---|---|
d+ |
( df1 df2 - - df3 ) |
Addition of two fixpoint numbers |
d- |
( df1 df2 - - df3 ) |
Subtraction of two fixpoint numbers |
f/ |
( df1 df2 - - df3 ) |
Division of two fixpoint numbers |
f* |
( df1 df2 - - df3 ) |
Multiplication |
hold< |
( char - - ) |
Adds character to pictured number output buffer from behind |
f#S |
( n-comma1 - - n-comma2 ) |
Adds 32 comma-digits to number output |
f# |
( n-comma1 - - n-comma2 ) |
Adds one comma-digit to number output |
f. |
( df - - ) |
Prints a fixpoint number with 32 fractional digits |
f.n |
( df n - - ) |
Prints a fixpoint number with n fractional digits |
number |
( c-addr length - - 0 ) |
Tries to convert a string to a number. 0 = FAILED |
( c-addr length - - n 1 ) |
1 = success, a 32 byte number is on the STACK |
|
( c-addr length - - n-low n-high 2 ) |
2 = success, TWO 32 bit numbers, a HIGH BYTE and a LOW BYTE on the STACK |
|
Decision Making¶
Single-Comparisons¶
exactly ANS, some logical extensions |
||
|---|---|---|
Unigned Comparisons |
||
u<= |
( u1 u2 - - flag ) |
u1 less-or-equal u2 |
u>= |
( u1 u2 - - flag ) |
u1 greater-or-equal u2 |
u> |
( u1 u2 - - flag ) |
u1 greater-than u2 |
u< |
( u1 u2 - - flag ) |
u1 less-than u2 |
Signed Comparisons¶
exactly ANS, some logical extensions |
||
|---|---|---|
<= |
( n1 n2 - - flag ) |
n1 less-or-equal n2 |
>= |
( n1 n2 - - flag ) |
n1 greater-or-equal n2 |
> |
( n1 n2 - - flag ) |
n1 greater-than n2 |
< |
( n1 n2 - - flag ) |
n1 less-than n2 |
0< |
( n - flag ) |
n less than zero |
0<> |
( n - - flag ) |
n not equal to zero |
0= |
( n - - flag ) |
n equals zero |
<> |
( n1 n2 - - flag ) |
n1 not-equals n2 |
= |
( n1 n2 - - flag ) |
n1 equals n2 |
Double-Comparisons¶
They perform the same for double numbers. |
|
|---|---|
du> |
( ud1 ud2 - - flag ) |
du< |
( ud1 ud2 - - flag ) |
d> |
( d1 d2 - - flag ) |
d< |
( d1 d2 - - flag ) |
d0< |
( d - - flag ) |
d0= |
( d - - flag ) |
d<> |
( d1 d2 - - flag ) |
d= |
( d1 d2 - - flag ) |
Bits: Test, Toggle, Clear and Set¶
Note: TRUE = 1, FALSE = 0. If a Bit is HIGH it leaves TRUE on the stack, otherwise FALSE
Word |
Stack Comment |
Description |
|---|---|---|
cbit@ |
( mask c-addr - - flag ) |
Test bit in byte-location |
hbit@ |
( mask h-addr - - flag ) |
Test bit in halfword-location |
( mask a-addr - - flag ) |
Test bit in word-location |
|
cxor! |
( mask c-addr - - ) |
Toggle bit in byte-location |
hxor! |
( mask h-addr - - ) |
Toggle bit in halfword-location |
xor! |
( mask a-addr - - ) |
Toggle bit in word-location |
cbic! |
( mask c-addr - - ) |
Clear bit in byte-location |
hbic! |
( mask h-addr - - ) |
Clear bit in halfword-location |
bic! |
( mask a-addr - - ) |
Clear bit in word-location |
cbis! |
( mask c-addr - - ) |
Set bit in byte-location |
hbis! |
( mask h-addr - - ) |
Set bit in halfword-location |
bis! |
( mask a-addr - - ) |
Set bit in word-location |
Memory Status¶
Word |
Stack Comment |
Description |
|---|---|---|
unused |
( - - free memory ) |
Displays memory depending on compile mode (Ram or Flash) |
Memory Access¶
subtle differences to ANS, special cpu-specific extensions
Fetch-Modify-Store operations like +! or bic! are NOT ATOMIC.
Word |
Stack Comment |
Description |
|
|---|---|---|---|
move |
( c-addr1 c-addr2 u - - ) |
Moves u Bytes in Memory |
|
fill |
( c-addr u c ) |
Fill u Bytes of Memory with value c |
|
2constant name |
( ud|d - - ) |
Makes a double constant. |
Y |
constant name |
( u|n - - ) |
Makes a single constant. i.e. “$1024 constant one-kb” |
Y |
2variable name |
( ud|d - - ) |
Makes an initialized double variable |
Y |
variable name |
( u|n - - ) |
Makes an initialized single variable. i.e. “0 variable one-kb” |
Y |
nvariable name |
( n1*u|n n1 - - ) |
Makes an initialized variable with specified size of n1, Maximum is 15 words |
Y |
buffer: name |
( u - - ) |
Creates a buffer in RAM u bytes in length |
Y |
2@ |
( a-addr - - ud|d ) |
Fetches double number from memory |
|
2! |
( ud|d a-addr - - ) |
Stores double number in memory |
|
@ |
( a-addr - - u|n ) |
Fetches single number from memory |
|
! |
( u|n a-addr - - ) |
Stores single number in memory |
|
+! |
( u|n a-addr - - ) |
Plus Store, use to increment a variable, register etc |
|
h@ |
( c-addr - - char ) |
Fetches halfword from memory |
|
h! |
( char c-addr ) |
Stores halfword in memory |
|
h+! |
( u|n a-addr - - ) |
Add to halfword memory location |
|
c@ |
( c-addr - - char ) |
Fetches byte from memory |
|
c! |
( char c-addr ) |
Stores byte in memory |
|
c+! |
( u|n a-addr - - ) |
Add to byte memory location |
String Formatting¶
String Routines¶
Warning
“ may not render properly on your browser, hence copying and pasting commands that use “ may fail. Click on “Show Source” to see the correct character.
exactly ANS, some logical extensions |
|||
|---|---|---|---|
type |
( c-addr length - - ) |
Prints a string. |
|
s” Hello” |
( - - c-addr length ) |
Compiles a string and gives back its address and length when executed |
|
.” Hello” |
( - - ) |
Compiles a string and prints it when executed. |
|
( Comment ) |
Ignore Comment |
||
\ Comment |
Comment to end of line |
||
cr |
( - - ) Emits line feed |
||
bl |
( - - 32 ) ASCII for Space |
||
space |
( - - ) Emits space |
||
spaces |
( n - - ) |
Emits n spaces if n is positive |
|
( caddr-1 len-1 c-addr-2 len-2 - - flag ) |
Compares two strings |
||
accept |
( c-addr maxlength - - length ) |
Read input into a string. |
|
Counted String Routines¶
Warning
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exactly ANS, some logical extensions |
||
|---|---|---|
ctype |
( cstr-addr - - ) |
Prints a counted string. |
c” Hello” |
( - - cstr-addr ) |
Compiles a counted string and gives back its address when executed. |
cexpect |
( cstr-addr maxlength - - ) |
Read input into a counted string. |
count |
( cstr-addr - - c-addr length ) |
Convert counted string into addr-length string |
skipstring |
( cstr-addr - - a-addr ) |
Increases the pointer to the aligned end of the string. |
Pictured Numerical Output¶
Pictured Numerical output |
||
|---|---|---|
.digit |
( u - - char ) |
Converts a digit to a char |
digit |
( char - - u true | false ) |
Converts a char to a digit |
[char] * |
( - - char ) |
Compiles code of following char when executed |
char * |
( - - char ) |
gives code of following char |
hold |
( char - - ) |
Adds character to pictured number output buffer from the front. |
hold< |
( char - - ) |
Adds character to pictured number output buffer from behind |
sign |
( n - - ) |
Add a minus sign to pictured number output buffer, if n is negative |
#S |
( ud1|d1 - - 0 0 ) |
Add all remaining digits from the double length number to output buffer |
f#S |
( n-comma1 - - n-comma2 ) |
Adds 32 comma-digits to number output |
# |
( ud1|d1 - - ud2|d2 ) |
Add one digit from the double length number to output buffer |
f# |
( n-comma1 - - n-comma2 ) |
Adds one comma-digit to number output |
#> |
( ud|d - - c-addr len ) |
Drops double-length number and finishes pictured numeric output ready for type |
<# |
( - - ) |
Prepare pictured number output buffer |
( u - - ) |
Print unsigned single number |
|
. |
( n - - ) |
Print single number |
ud. |
( ud - - ) |
Print unsigned double number |
( d - - ) |
Print double number |
|
Deep Insights¶
Deep Insights |
||
|---|---|---|
words |
( - - ) |
Prints list of defined words and properties |
list |
( - - ) |
Prints all defined words. From; dissasembler-mx.txt |
.s |
( many - - many ) |
Prints stack contents, signed |
u.s |
( many - - many ) |
Prints stack contents, unsigned |
h.s |
( many - - many ) |
Prints stack contents, unsigned, hex |
hex. |
( u - - ) |
Prints 32 bit unsigned in hex base, needs emit only. This is independent of number subsystem. |
User Input and Interpretation¶
exactly ANS, some logical extensions |
||
|---|---|---|
query |
( - - ) |
Fetches user input to input buffer |
tib |
( - - cstr-addr ) |
Input buffer |
current-source |
( - - addr ) |
Double-Variable which contains source |
tsource |
( c-addr len - - ) |
Change source |
source |
( - - c-addr len ) |
Current source |
>in |
( - - addr ) |
Variable with current offset into source |
token |
( - - c-addr len ) |
Cuts one token out of input buffer |
parse |
( char - - c-addr len ) |
Cuts anything delimited by char out of input buffer |
evaluate |
( any addr len - - any ) |
Interpret given string |
interpret |
( any - - any ) |
Execute, compile, fold, optimize… |
quit |
( many - - ) (R: many - - ) |
Resets Stacks |
hook-quit |
( - - a-addr ) |
Hook for changing the inner quit loop |
Dictionary Expansion¶
exactly ANS, some logical extension |
||
|---|---|---|
align |
( - - ) |
Aligns dictionary pointer |
aligned |
( c-addr - - a-addr ) |
Advances to next aligned address |
cell+ |
( x - - x+4 ) |
Add size of one cell |
cells |
( n - - 4*n ) |
Calculate size of n cells |
allot |
( n - - ) |
tries to advance Dictionary Pointer by n bytes, aborts, if not enough space available |
here |
( - - a-addr|c-addr ) |
Gives current position in Dictionary |
, |
( u|n - - ) |
appends a single number to dictionary |
><, |
( u|n - - ) |
reverses high and low-halfword, then appends it to dictionary |
h, |
( u|n - - ) |
appends a halfword to dictionary |
compiletoram? |
( - - ? ) |
currently compiling into ram ? |
compiletoram |
( - - ) |
makes ram the target for compiling |
compiletoflash |
( - - ) |
makes flash memory the target for compiling |
forgetram |
( - - ) |
Forget definitions in ram without a reset |
Speciality!¶
Words |
Stack Comment |
Description |
|---|---|---|
string, |
( c-addr len - - ) |
Inserts a string of maximum 255 characters without runtime |
literal, |
( u|n - - ) |
Compiles a literal with runtime |
( a-addr - - ) |
Inlines the choosen subroutine |
|
call, |
( a-addr - - ) |
Compiles a call to a subroutine |
jump, |
( Hole-for-Opcode Destination ) |
Writes an unconditional Jump to a-addr-Destination with the given Bitmask as Opcode into the halfword sized h-addr-Hole |
cjump, |
( Hole-for-Opcode Destination Bitmask ) |
Writes a conditional Jump to a-addr-Destination with the given Bitmask as Opcode into the halfword sized h-addr-Hole |
ret, |
( - - ) |
compiles a ret opcode |
flashvar-here |
( - - a-addr ) |
Gives current RAM management pointer |
dictionarystart |
( - - a-addr ) |
Current entry point for dictionary search |
dictionarynext |
( a-addr - - a-addr flag ) |
Scans dictionary chain and returns true if end is reached. |
Special Words Depending on MCU Capabilities¶
Words |
Stack Comment |
Description |
|---|---|---|
( char - - ) |
Appends a byte to dictionary. NOT AVAILABLE ON ALL MCU’S. Check with ‘ c, or just look in ‘words’. |
|
halign |
( - - ) |
Makes Dictionary Pointer even, if uneven. |
movwmovt, |
( x Register - - ) |
Generate a movw/movt-Sequence to get x into any given Register. M3/M4 only |
( x Register - - ) |
Generate shortest possible sequenceto get x into given low Register. On M0: A movs-lsls-adds… sequence M3/M4: movs / movs-mvns / movw / movw-movt |
|
12bitencoding |
( x - - x false | bitmask true ) |
Can x be encoded as 12-bit immediate ? |
eraseflash |
( - - ) |
Erases everything after — Flash Dictionary — Clears Ram, Restarts Forth. Does not erase Mecrisp-Stellaris |
eraseflashfrom |
( a-addr – ) |
Starts erasing at this address. Clears Ram. Restarts Forth. |
flashpageerase |
( a-addr – ) |
Erase one 1k flash page only. Take care: No Reset, no dictionary reinitialisation. |
hflash! |
( u|n a-addr – ) |
Writes halfword to flash |
Flags and Inventory¶
Speciality! |
Stack Comment |
Description |
|---|---|---|
( - - ) |
Makes current definition visible, burns collected flags to flash and takes care of proper ending |
|
( - - ) |
Takes the code of a word, and puts it in place of a call to this word |
|
immediate |
( - - ) |
Will not compile this word into the dictionary but execute the word immediately |
compileonly |
( - - ) |
Makes current definition compileonly |
setflags |
( char - - ) |
Sets Flags with a mask. This isn’t immediate, |
(create) name |
( - - ) |
Names a location; space may be allocated at this location, or it can be set to contain a string or other initialized value. Instance behavior returns the address of the beginning of this space. Use FIG-style <builds .. does> ! |
find |
( c-addr len - - a-addr flags) |
Searches for a String in Dictionary. Gives back flags, which are different to ANS! |
Folding¶
Speciality! |
Stack Comment |
Description |
Applies To |
|---|---|---|---|
0-foldable |
( - - ) |
Current word becomes foldable with 0 constants |
constants variables [’] [char] |
1-foldable |
( - - ) |
1 constant |
?dup drop negate |
2-foldable |
( - - ) |
2 constants |
+ - * swap nip |
3-foldable |
( - - ) |
3 constants |
rot |
4-foldable |
( - - ) |
4 constants |
d+ d- 2swap |
5-foldable |
( - - ) |
5 constants |
|
6-foldable |
( - - ) |
6 constants |
|
7-foldable |
( - - ) |
7 constants |
Compiler Essentials¶
The true POWER of Forth resides in the Words listed in this table.
subtle differences to ANS |
||
|---|---|---|
execute |
( a-addr - - ) |
Calls subroutine |
recurse |
( - - ) |
Lets the current definition call itself |
‘ name |
( - - a-addr ) |
Tries to find name in dictionary gives back executable address |
[’] name |
( - - a-addr) |
Tick that compiles the executable address of found word as literal |
postpone |
( - - ) |
See Glossary |
( - - ) |
Makes Dictionary header and reserves space for special call. |
|
does> |
( - - ) |
executes: ( - -a-addr ) Gives address to where you have stored data. |
create name |
( - - ) |
Create a definition with default action which cannot be changed later. Use <builds does> instead. Equivalent to : create <builds does> ; |
state |
( - - a-addr ) |
Address of state variable |
] |
( - - ) |
|
[ |
( - - ) |
|
; |
( - - ) |
Finishes new definition |
: name |
( - - ) |
Opens new definition |
Control Structures¶
Internally, they have complicated compile-time stack effects.
Summary¶
Structure |
Description |
|---|---|
DO … LOOP |
Finite loop incrementing by 1 |
DO … +LOOP |
Finite loop incrementing by X |
BEGIN … UNTIL |
Indefinite loop terminating when is ‘true’ |
BEGIN … WHILE … REPEAT |
Indefinite loop terminating when is ‘false’ |
BEGIN … AGAIN |
Infinite loop |
IF … ELSE … THEN |
Two-branch conditional; performs words following IF it is ‘true’ and words following ELSE if it is ‘false’. THEN marks the point at which the paths merge. |
IF … THEN |
Like the two-branch conditional, but with only a ‘true’ clause. |
Decisions¶
Decisions |
exactly ANS |
|
|---|---|---|
then |
( - - ) |
This is the common flag if … [else …] then structure. |
else |
( - - ) |
flag if … [else …] then |
if |
( flag - - ) |
structure. |
Syntax¶
“IF that’s the case, do this, ELSE do that … and THEN continue with …”
flag if ... then
flag if ... else ... then
Case¶
Case |
exactly ANS |
|
|---|---|---|
case |
( n - -n ) |
Begins case structure |
of |
( m - - ) |
Compares m with n, choose this if n=m |
?of |
( n flag - - ) |
Flag-of, for custom comparisions |
endof |
( - - ) |
End of one possibility |
endcase |
( n - - ) |
Ends case structure, discards n |
Syntax¶
n case
m1 of ... endof
m2 of ... endof
flag ?of ... endof
all others
endcase
Indefinite Loops¶
A loop structure in which the words contained within the loop continue to repeat until some truth condition changes state (true-to-false or false-to-true). In Forth, the indefinite loops begin with the word BEGIN.
Indefinite Loops |
Stack Comment |
Exactly ANS |
|---|---|---|
repeat |
( - - ) |
Finish of a middle-flag-checking loop. |
while |
( flag - - ) |
Check a flag in the middle of a loop |
until |
( flag - - ) |
Begin … flag until loops as long flag is true |
again |
( - - ) |
begin … again is an endless loop |
begin |
( - - ) |
Syntax¶
begin ... again
begin ... flag until
begin ... flag while ... repeat
Definite Loops¶
A loop structure in which the words contained within the loop repeat a definite number of times. In Forth, this number depends on the starting and ending counts (index and limit) which are placed on the stack prior to the execution of the word DO.
Definite Loops |
Stack Comment |
Exactly ANS |
|---|---|---|
i |
( - -u|n ) |
Gives innermost loop index |
j |
( - -u|n ) |
Gives second loop index |
k |
( - -u|n ) |
Gives third loop index |
unloop |
(R: old-limit old-index - - ) |
Drops innermost loop structure, pops back old loop structures to loop registers |
exit |
( - - ) |
Returns from current definition. Compiles a ret opcode. |
leave |
( - - ) (R: old-limit old-index - - ) |
Leaves current innermost loop promptly |
( u|n - - ) (R: unchanged | old-limit old-index - - ) |
If you want the index to go up by some number other than one each time around. |
|
( - - ) (R: unchanged | old-limit old-index - - ) |
Increments current loop index register by one and checks whether to continue or not. |
|
?do |
( Limit Index - - ) (R: unchanged | - -old-limit old-index ) |
Begins a loop if limit and index are not equal |
( Limit Index - - ) (R: - -old-limit old-index ) |
Begins a loop |
Syntax¶
limit index do ... loop
Common Hardware Access¶
reset |
( - - ) |
Reset on hardware level |
dint |
( - - ) |
Disables Interrupts |
eint |
( - - ) |
Enables Interrupts |
eint? |
( - - ) |
Are Interrupts enabled ? |
nop |
( - - ) |
No Operation. Hook for unused handlers ! |
ipsr |
( - - ipsr ) |
Interrupt Program Status Register |
unhandled |
( - - ) |
Message for unhandled interrupts. |
irq-systick |
( - - a-addr ) |
Memory locations for IRQ-Hooks |
irq-fault |
( - - a-addr ) |
For all faults |
irq-collection |
( - - a-addr ) |
Collection of all unhandled interrupts |
