Stackmill

Stackmill is an esoteric programming language created by User:Asiekierka on 25th December 2010.

Commands

00xx - input value xx (in binary) to stack
0100 - NAND the two top values on stack (8-bit)
0101 - pop value on stack
0110 - shift entire stack up
0111 - shift entire stack down
1000..1001 - execute code inbetween while the topmost stack value is nonzero
1010 - output value (as number or char, depends on implementation this time)
1011 - input value (as char)
11xx - perform an operation on 2 topmost values:

when xx is:
00 - +
01 - -
10 - *
11 - /

for example,
1101 (subtraction)

stack:
3	->	1
2		0
0

The bitwidth is up to the interpreter (default: 32 bits signed). The input/output method is also up to the interpreter (asiekierka's outputs as numbers and inputs as chars)

Examples

Fibonacci

0010 1010 0011 1010 // initialize and output 2 and 3
1000 // start loop, first run is 2 and 3
0000 0000 0110 0110
1000 0001 1101 0000 1101 0111 0001 1100 0111 0001 1100 0110 0110 1001
0101 0110 0110 // duplicate the bigger value
1100 1010 // add them up 
1001 // end loop, 3 and 5 should be on stack on first run

Turing-completeness

A sub-Turing complete variant of brainfuck with a fixed-length tape can be translated to Stackmill. First, push n elements, where n is the size of the tape. Then:

< 0110
> 0111
[ 1000
] 1001
+ 0001 1100
- 0001 1101 0000 1101
, 1011
. 1010

Bitwise Cyclic Tag can be implemented in Stackmill, though, using these instructions:

0 pop the topmost stack value
1 if topmost stack value is 1, push the next input value (0 or 1) on stack then shift up
loop and exit condition: push a non-BCT value (for example, 3), then shift up. if you get the same value, the stack is empty. halt. otherwise shift down and pop value, continue execution.

Downloads

• asiekierka's Stackmill interpreter
• Port of the above Stackmill interp to the GBA