The Stack

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Alternate stack results shown with space, e.g. ( input -- addr len false | result true ). 

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Alternate stack items shown without space, e.g. ( input -- addr len|0 result ). 

???

Unknown stack item(s). 

Unknown stack item(s). If used on both sides of a stack comment, means the same stack items are present on both sides. 

< > <space>

Space delimiter. Leading spaces are ignored. 

a-addr

Variable-aligned address. 

addr

Memory address (generally a virtual address). 

addr len

Address and length for memory region 

byte bxxx

8-bit value (low order byte in a 32-bit word). 

char

7-bit value (low order byte), high bit unspecified. 

cnt len size

Count or length. 

dxxx

Double (extended-precision) numbers. 2 stack items, hi quadlet on top of stack. 

<eol>

End-of-line delimiter. 

false

0 (false flag). 

ihandle

Pointer for an instance of a package. 

n n1 n2 n3

Normal signed values (32-bit). 

nu nu1

Signed or unsigned values (32-bit). 

<nothing>

Zero stack items. 

phandle

Pointer for a package. 

phys

Physical address (actual hardware address). 

phys.lo phys.hi

Lower / upper cell of physical address 

pstr

Packed string. 

quad qxxx

Quadlet (32-bit value). 

qaddr

Quadlet (32-bit) aligned address 

{text}

Optional text. Causes default behavior if omitted. 

"text<delim>"

Input buffer text, parsed when command is executed. Text delimiter is enclosed in <>. 

[text<delim>]

Text immediately following on the same line as the command, parsed immediately. Text delimiter is enclosed in <>. 

true

-1 (true flag). 

uxxx

Unsigned value, positive values (32-bit). 

virt

Virtual address (address used by software). 

waddr

Doublet (16-bit) aligned address 

word wxxx

Doublet (16-bit value, low order two bytes in a 32-bit word). 

x x1

Arbitrary stack item. 

x.lo x.hi

Low/high significant bits of a data item 

xt

Execution token. 

xxx?

Flag. Name indicates usage (e.g. done? ok? error?).

xyz-str xyz-len

Address and length for unpacked string. 

xyz-sys

Control-flow stack items, implementation-dependent. 

( C: -- )

Compilation stack diagram 

( -- ) ( E: -- )

Execution stack diagram 

( R: -- )

Return stack diagram 

-rot

( x1 x2 x3 -- x3 x1 x2 ) 

Inversely rotate 3 stack items. 

>r

( x -- ) (R: -- x ) 

Move a stack item to the return stack. (Use with caution.) 

?dup

( x -- x x | 0 ) 

Duplicate the top stack item if it is non-zero. 

2drop

( x1 x2 -- ) 

Remove 2 items from the stack. 

2dup

( x1 x2 -- x1 x2 x1 x2 ) 

Duplicate 2 stack items. 

2over

( x1 x2 x3 x4 -- x1 x2 x3 x4 x1 x2 ) 

Copy second 2 stack items. 

2rot

( x1 x2 x3 x4 x5 x6 -- x3 x4 x5 x6 x1 x2 ) 

Rotate 3 pairs of stack items. 

2swap

( x1 x2 x3 x4 -- x3 x4 x1 x2 ) 

Exchange 2 pairs of stack items. 

3drop

( x1 x2 x3 -- ) 

Remove 3 items from the stack. 

3dup

( x1 x2 x3 -- x1 x2 x3 x1 x2 x3 ) 

Duplicate 3 stack items. 

clear

( ??? -- ) 

Empty the stack. 

depth

( -- u ) 

Return the number of items on the stack. 

drop

( x -- ) 

Remove top item from the stack. 

dup

( x -- x x )  

Duplicate the top stack item. 

nip

( x1 x2 -- x2 ) 

Discard the second stack item. 

over

( x1 x2 -- x1 x2 x1 ) 

Copy second stack item to top of stack. 

pick

( xu ... x1 x0 u -- xu ... x1 x0 xu ) 

Copy u-th stack item (1 pick = over).

r>

( -- x ) ( R: x -- ) 

Move a return stack item to the stack. (Use with caution.)  

r@

( -- x ) ( R: x -- x ) 

Copy the top of the return stack to the stack.  

roll

( xu ... x1 x0 u -- xu-1 ... x1 x0 xu ) 

Rotate u stack items (2 roll = rot).

rot

( x1 x2 x3 -- x2 x3 x1 ) 

Rotate 3 stack items. 

swap

( x1 x2 -- x2 x1 ) 

Exchange the top 2 stack items. 

tuck

( x1 x2 -- x2 x1 x2 ) 

Copy top stack item below second item.