Instructions recognized by the GPMachine are defined in Reinard Wilhelm and Dieter Maurer, Compiler Design.
The way several p-instruction are interpreted differs in GPMachine 3.0 from previous versions. GPMachine now follows strictly Wilhelm and Maurer definition. The only two exceptions are the I/O instructions :
| Instruction | Semantics |
|---|---|
| read | STORE[SP] = <element read (integer only)> SP = SP+1 |
| Instruction | Semantics |
|---|---|
| prin | print the content of STORE[SP] (integer only) SP = SP-1 |