OpenBoot 3.x Quick Reference

Numeric Usage and Stack Comments

A numeric stack is used for all numeric parameters. Typing any integer puts that value on top of the stack. (Previous values are pushed down.) The right-hand item in a set always indicates the topmost stack item.

A stack comment such as (n1 n2 -- n3) or (adr len --) or (--) listed after each command name shows the effect on the stack of executing that command. Items before the -- are used by the command and removed from the stack. These items must be present on the stack before the command can properly execute. Items after the -- are left on the stack after the command completes execution, and are available for use by subsequent commands.

Table 1-1 Numeric Usage and Stack Comments


Alternate stack results. Example: ( input -- adr len false | result true ). 


Unknown stack items (changed from ???).


Unknown stack items. 


Memory address (generally a virtual address). 


Memory address, must be 16-bit aligned. 


Memory address, must be 32-bit aligned. 


Memory address, must be 64-bit aligned. 

byte bxxx

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


7-bit value (smallest byte), high bit unspecified. 


Count or length.  

flag xxx?

0 = false; any other value = true (usually -1). 

long lxxx

32-bit value. 

n n1 n2 n3

Normal signed values. 

+n u

Unsigned, positive values. 


Physical address (actual hardware address). 


Packed string (adr len means unpacked string).


Virtual address (address used by software). 

word wxxx

16-bit value. 


Execution token.