The purpose of the API is to serve as an instruction set reference for the MOS 6502. It returns JSON objects when queried, and returns nothing if the specified instruction or instruction/addressing mode combo cannot be found. The fact number uses a modulus and so querying for a specific fact number will always return something.
The API can be accessed at http://rlannon.heroku.com/api/v1/6502/<path here> from any domain. The API should typically be accessed with GET requests, but a few paths support POST requests as well, one for accessing data and one for updating the database. Currently, the application does not require authentication or an API key. Please use it responsibly.
| Path | Description |
|---|---|
/instructions |
Returns a list of all instructions. Supports HTTP POST requests for fetching JSON data as well. The form that is submitted must have inputs with the names mnemonic and addressing_mode; the former is required and must be all caps, the latter is optional |
/instructions/<mnemonic> |
Return all information for a specific instruction |
/instructions/<mnemonic>/<addressing mode> |
Returns the opcode, instruction length, and execution time for an instruction with the given addressing mode |
/flags |
Returns information about all processor flags |
/flags/<flag> |
Returns information about the specified flag |
/facts |
Returns a list of facts about the 6502 |
/fact |
Returns a random fact from our list |
/fact/<number> |
Returns a specific fact |
/facts/add |
Supports HTTP POST requests for adding a fact to the database. Form must have an input with the name fact or the request will be ignored |
The mnemonic should be the 3-letter instruction mnemonic in caps. The available addressing modes are:
| Code | Addressing mode |
|---|---|
imm |
Immediate addressing |
zp |
Zero page |
zp,x |
Zero page, X |
zp,y |
Zero page, Y |
abs |
Absolute |
abs,x |
Absolute, X |
abs,y |
Absolute, Y |
ind |
Indirect |
ind,x |
Indirect, X (indexed indirect) |
ind,y |
Indirect, Y (indirect indexed) |
a |
A register |
impl |
Implied |
The flag should be followed by a char with the flag identifier:
* N - Negative
* V - Overflow
* B - Break
* D - Decimal
* I - Interrupt disable
* Z - Zero
* C - Carry
Information returned about instructions includes:
| Field | Description |
|---|---|
mnemonic |
The 3-letter mnemonic for the instruction |
name |
The name of the instruction |
description |
A brief description of the instruction |
flags |
The flags affected by the instruction |
Information returned about specific isntructions includes:
| Field | Description |
|---|---|
mnemonic |
The 3-letter mnemonic for the instruction |
addressing_mode |
The addressing mode (see above for codes) |
opcode |
The opcode for the instruction |
length |
The length of the instruction (in bytes) |
time |
The number of cycles it takes to execute the instruction |
page_boundary_increase |
Whether the execution time increases when a page boundary is crossed |
Fact information returns a string fact containing the fact.
Flags information returns:
| Field | Description |
|---|---|
flag |
A char with the flag identifier |
name |
The name of the flag |
description |
The description of the flag and its use |