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Updated Instruction Set (markdown)

Simon Fortier 2017-12-28 13:14:29 -05:00
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Instruction-Set.md

@ -38,4 +38,19 @@
*NEG instruction: CF is set to 0 if destination=0
### Instruction encoding
WIP
Instructions are 1-3 words long and are fully defined by the first word.
In a basic instruction, the lower 6 bits of the first word of the instruction
are the opcode, and the remaining 12 bits are split into a 5 bit destination operand
and a 5 bit source operand.
In bits, a basic instruction has the format: `sssssdddddoooooo`
Operand value:
| Description | Value |
| --- | --- |
| Invalid or none | `00000` |
| Immediate value at IP+1 | `11111` |
| [Immediate value at IP+1] | `11110` |
| Register | `00001`-`01000` |
| [Register] | `01001`-`10000` |
| Register + Immediate value at IP+1 | `10001`-`11000` |