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Drake 1 year ago
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</tr>
</tbody>
</table>
<h4>LDX - Load [RA]Y</h4>
<h4>LDY - Load [RA]Y</h4>
<p>loads a value into RAY</p>
<table>
<thead>
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</tr>
</tbody>
</table>
<h4>Sub - Subtracts Two Values</h4>
<h4>SUB - Subtracts Two Values</h4>
<p>subtracts two values of various source into a register or memory address</p>
<table>
<thead>
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</tr>
</tbody>
</table>
<h4>NAD - NAND</h4>
<p>if you don’t know what a NAND is why are you looking at opcode documentation</p>
<table>
<thead>
<tr>
<th>Addressing</th>
<th>Action</th>
<th>Opcode</th>
<th>Size</th>
</tr>
</thead>
<tbody>
<tr>
<td>Register</td>
<td>Performs a bitwise NAND on RAX and RAY and stores it into ACC</td>
<td><code>$50</code></td>
<td>1 byte</td>
</tr>
</tbody>
</table>
<h4>HLT - Halt Operation</h4>
<p>entirely stops execution and attempts to shutdown on hardware</p>
<table>

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## LRIS CPU/ASM specification (wip)
~~shamelessly ripped off~~ very inspired by 6502 because it's the only thing i kinda know
### Registers
| Register | Purpose | Size |
| --- | --- | --- |
| ACC | Stores the result of any calculation opcodes (if in ACC mode) | 1 byte |
| RAX | General purpose register | 1 byte |
| RAY | General purpose register | 1 byte |
### Memory
- Up to 64kib of RAM
- Up to 64kib of Program ROM
### Addressing Modes
#### Absolute
Directly reads from a 2 byte memory address with instruction.
```
LDX $0A2F
```
<sub><sup>Note: 1 byte addresses should be padded by the assembler.</sup></sub>
#### Literal
Uses a literal byte, in place of reading from a memory address.
```
LDX #0A2F
```
<sub><sup>Note: 1 byte addresses should be padded by the assembler.</sup></sub>
### Opcodes
NOTE: these do not specify a higher level assembly langauge, only the opcodes interpreted by the CPU itself (ie there cannot be 3 increments for the different registers that all use `INC`)
#### NOP- No Operation
seriously?
| Addressing | Action | Opcode | Size |
| --- | --- | --- | --- |
| N/A | NOP | `$00` | 1 byte |
#### INC - Increment
what do you think it does
| Addressing | Action | Opcode | Size |
| --- | --- | --- | --- |
| Absolute | Increments the value at specified memory address | `$01` | 3 bytes |
| Accumulator | Increments the accumulator | `$02` | 1 byte |
| RX | Increments the RAX register | `$03` | 1 byte |
| RY | Increments the RAY register | `$04` | 1 byte |
#### DNC - Decrement
what do you think it does (pt. 2)
| Addressing | Action | Opcode | Size |
| --- | --- | --- | --- |
| Absolute | Decrements the value at specified memory address | `$05` | 3 bytes |
| Accumulator | Decrements the accumulator | `$06` | 1 byte |
| RX | Decrements the RAX register | `$07` | 1 byte |
| RY | Decrements the RAY register | `$08` | 1 byte |
#### JIE - Jump If Equal
jumps if something is equal to other something
| Addressing | Action | Opcode | Size |
| --- | --- | --- | --- |
| Absolute/Literal | Sets PRC to value if memory address is equal to other memory address | `$10` | 7 bytes |
| Register/Literal | Sets PRC to value if RAX and RAY are equal | `$11` | 1 byte |
#### JMP - Jump
jumps unconditionally
| Addressing | Action | Opcode | Size |
| --- | --- | --- | --- |
| Literal | Sets PRC to a literal value | `$1A` | 3 bytes
| Absolute | Sets PRC to the value of a byte in memory | `$1B` | 3 bytes
##### Example:
```
;OP PRC ADDR ADDR
JIE 0x00A2 0x0013 0x0014
```
#### LDX - Load [RA]X
loads a value into RAX
| Addressing | Action | Opcode | Size |
| --- | --- | --- | --- |
| Absolute | Loads the value of another byte of memory into RAX | `$20` | 3 bytes |
| Literal | Loads a literal byte into RAX | `$21` | 2 bytes |
#### LDY - Load [RA]Y
loads a value into RAY
| Addressing | Action | Opcode | Size |
| --- | --- | --- | --- |
| Absolute | Loads the value of another byte of memory into RAY | `$22` | 3 bytes |
| Literal | Loads a literal byte into RAY | `$23` | 2 bytes |
#### LDA - Load A(ccumulator)
loads a value into the accumulator
| Addressing | Action | Opcode | Size |
| --- | --- | --- | --- |
| Absolute | Loads the value of another byte of memory into ACC | `$24` | 3 bytes |
| Literal | Loads a literal byte into ACC | `$25` | 2 bytes |
#### LOD - Load Address
loads a value into an address
| Addressing | Action | Opcode | Size |
| --- | --- | --- | --- |
| Absolute | Loads the value of another byte of memory into the memory address | `$26` | 5 bytes |
| Literal | Loads a literal byte into the memory address | `$27` | 4 bytes |
#### STX - Store [RA]X
stores RAX into a memory address
| Addressing | Action | Opcode | Size |
| --- | --- | --- | --- |
| Absolute | Loads the value of RAX into a byte of memory | `$2A` | 3 bytes |
#### STY - Store [RA]Y
stores RAY into a memory address
| Addressing | Action | Opcode | Size |
| --- | --- | --- | --- |
| Absolute | Loads the value of RAY into a byte of memory | `$2B` | 3 bytes |
#### STA - Store A(ccumulator)
stores the accumulator into a memory address
| Addressing | Action | Opcode | Size |
| --- | --- | --- | --- |
| Absolute | Loads the value of ACC into a byte of memory | `$2C` | 3 bytes |
#### ADD - Adds Two Values
adds two values of various source into a register or memory address
| Addressing | Action | Opcode | Size |
| --- | --- | --- | --- |
| RAX | Adds RAX to the value in ACC, and stores it into ACC | `$40` | 1 byte |
| RAY | Adds RAY to the value in ACC, and stores it into ACC | `$41` | 1 byte |
| Absolute/Absolute | Adds the values of two memory addresses, and stores it into ACC | `$42` | 5 bytes |
| Absolute/ACC | Adds the value of a memory address into the value in ACC, and stores it into ACC | `$43` | 3 bytes |
#### SUB - Subtracts Two Values
subtracts two values of various source into a register or memory address
| Addressing | Action | Opcode | Size |
| --- | --- | --- | --- |
| RAX | Subtracts RAX from the value in ACC, and stores it into ACC | `$45` | 1 byte |
| RAY | Subtracts RAY from the value in ACC, and stores it into ACC | `$46` | 1 byte |
| Absolute/Absolute | Subtracts the first address' value by the second address' value, and stores it into ACC | `$47` | 5 bytes |
| Absolute/ACC | Subtracts the value of a memory address from the value in ACC, and stores it into ACC | `$48` | 3 bytes |
#### NAD - NAND
if you don't know what a NAND is why are you looking at opcode documentation
| Addressing | Action | Opcode | Size |
| --- | --- | --- | --- |
| Register | Performs a bitwise NAND on RAX and RAY and stores it into ACC | `$50` | 1 byte |
#### HLT - Halt Operation
entirely stops execution and attempts to shutdown on hardware
| Addressing | Action | Opcode | Size |
| --- | --- | --- | --- |
| N/A | | `$FC` | |
#### DBG - Debug
(in emulators) print a view of memory
(in hardware or an optimizing assembler) NOP
| Addressing | Action | Opcode | Size |
| --- | --- | --- | --- |
| N/A | | `$FF` | |