Microsoft has experimented with Native (AOT) compilation for .NET core via a number of projects, specifically CoreRT. One of the main goals in this experimentation has been to see how much of the .NET runtime can be implemented in C# itself. In so doing this has opened the door for fun experiments such as the minimal C# snake game in 8Kb.
CSharp-80 was inspired by the C# snake game and is an attempt to build a AOT compiler for .NET targetting a retro 8 bit microcomputer, specifically the TRS-80 Model 1, which can compile the snake game.
CSharp-80 Architecture is similar to CoreRT in consuming CIL as input but generated Z80 Assembly language as output which can easily be turned into a native TRS-80 command file using an assembler such as zmac.
| Instruction | Supported types |
|---|---|
| ldc.i4.0 | |
| ldc.i4.1 | |
| ldc.i4.2 | |
| ldc.i4.3 | |
| ldc.i4.4 | |
| ldc.i4.5 | |
| ldc.i4.6 | |
| ldc.i4.7 | |
| ldc.i4.8 | |
| ldc.i4 | |
| ldc.i4.s | |
| stloc.0 | int32 |
| stloc.1 | int32 |
| stloc.2 | int32 |
| stloc.3 | int32 |
| ldloc.0 | int32 |
| ldloc.1 | int32 |
| ldloc.2 | int32 |
| ldloc.3 | int32 |
| stind.i1 | |
| add | int32 |
| sub | int32 |
| mul | int32 |
| div | int32 |
| div.un | int32 |
| rem.un | int32 |
| neg | int32 |
| br.s | int32 |
| blt.s | int32 |
| bgt.s | int32 |
| ble.s | int32 |
| bge.s | int32 |
| beq.s | int32 |
| bne.un.s | int32 |
| brfalse.s | int32 |
| brtrue.s | int32 |
| br | int32 |
| blt | int32 |
| bgt | int32 |
| ble | int32 |
| bg | int32 |
| beq | int32 |
| bne.un | int32 |
| brfalse | int32 |
| brtrue | int32 |
| ldarg.0 | int32 |
| ldarg.1 | int32 |
| ldarg.2 | int32 |
| ldarg.3 | int32 |
| ldarg | int32 |
| ldarg.s | int32 |
| starg | int32 |
| starg.s | int32 |
| ldstr | Very simple implementation not really using proper object representation for string |
| ret | |
| call |