Instruction set

This page documents the instructions supported by the J1a, Mecrisp Ice J1a and the Hana 1 hardware. All of the other words, documented in the glossary are built using these instructions.

Here are the abbreviations used on this page.

a address of 16 bit value
c address of 8 bit value (usually a character)
d is a double number
n means a number
u means unsigned number
x anything
ud unsigned double
xd double anything
true 1111_1111_1111_1111
false 0000_0000_0000_0000
| or as in u|n

#.  noop     No Operation.  Nothing changes.
#.  +       ( u1|n1 u2|n2 -- u3|n3 ) Addition
#.  -       ( u1|n1 u2|n2 -- u3|n3 ) Subtraction
#.  xor     ( x1 x2 -- x3 ) Bitwise Exclusive-OR
#.  and     ( x1 x2 -- x3 ) Bitwise AND
#.  or      ( x1 x2 -- x3 ) Bitwise OR
#.  invert  ( x1 -- x2 )   Invert all bits
#.  =       ( x1 x2 -- flag )   Test for Equality
#.  <       ( n1 n2 -- flag )
#.  u<      ( u1 u2 -- flag )
#.  swap    ( x1 x2 -- x2 x1 )
#.  dup     ( x -- x x )
#.  drop    ( x -- )
#.  over    ( x1 x2 -- x1 x2 x1 )
#.  nip     ( x1 x2 -- x2 )
#.  >r      ( x -- ) (R: -- x )
#.  r>      ( -- x ) (R: x -- )
#.  r@      ( -- x ) (R: x -- x )
#.  !       ( u|n a-addr -- ) Stores single number in memory
#.  io!     ( x c-addr -- ) Stores  into IO register
#.  2/     ( n1 -- n2 ) Arithmetric right-shift
#.  2*     ( n1 -- n2 ) Arithmetric  left-shift
#.  exit
#.  hack  ( addr data  -- addr) \ writes data to io

Elided Words

For more advanced users, the J1 includes elided, which execute two or more ANSI words in one clock cycle. You can read more at the bottom of the SwapForth instruction page All of the J1 elided words are available in the cross compiled nucleus.

Mecrisp Ice

Mecrisp Ice adds the following words to the J1a insruction set.

#.   1-       ( u1|n1 -- u2|n2 ) Subtracts one, optimized
#.   1+       ( u1|n1 -- u2|n2 ) Adds one, optimized
#.   io@      ( c-addr -- x ) Fetches from IO register
#.   @        ( a-addr -- u|n ) Fetches single number from memory
#.   lshift   (x1 u -- x2 ) Logical  left-shift of u bit-places
#.   rshift   ( x1 u -- x2 ) Logical right-shift of u bit-places
#.   dint     ( -- ) Disable interrupt
#.   eint     ( -- ) Enable ticks counter overflow interrupt
#.   arshift  ( x1 u -- x2 ) Arithmetric right-shift of u bit-places
#.   rdepth   ( -- +n ) return stack depth.
#.   um*low   ( u1 u2 -- ud )  16bit * 16bit = 32 bit multiplication low bits
#.   um*high  ( u1 u2 -- ud )  16bit * 16bit = 32 bit multiplication high bits

You can read the list of elided words for Mecrisp Ice in the repository. I am not sure if the two sets of elided words differ or not. But only those elided words listed in the Mecrisp Ice nucleus-*.fs file are included in the cross compiled code.

Hana 1

The Hana 1 has 3 additional commands for controlling the SPI bus.

#.   spi@   ( -- data )   Read a 16 bit value from SPI.
#.   spi!  ( data addr -- )  Write a 16 bit value to SPI.
#.   cs-   ( -- )  Turn off chip select for the FLASH.

Flash chip select is turned on automatically when writing to FLASH.